| 1 | <!DOCTYPE html |
|---|
| 2 | PUBLIC "-//W3C//DTD HTML 4.01//EN"> |
|---|
| 3 | <html lang="en"> |
|---|
| 4 | <head profile="http://www.w3.org/2006/03/hcard"> |
|---|
| 5 | <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> |
|---|
| 6 | <title>HTTP/1.1, part 3: Message Payload and Content Negotiation</title><style type="text/css" title="Xml2Rfc (sans serif)"> |
|---|
| 7 | a { |
|---|
| 8 | text-decoration: none; |
|---|
| 9 | } |
|---|
| 10 | a.smpl { |
|---|
| 11 | color: black; |
|---|
| 12 | } |
|---|
| 13 | a:hover { |
|---|
| 14 | text-decoration: underline; |
|---|
| 15 | } |
|---|
| 16 | a:active { |
|---|
| 17 | text-decoration: underline; |
|---|
| 18 | } |
|---|
| 19 | address { |
|---|
| 20 | margin-top: 1em; |
|---|
| 21 | margin-left: 2em; |
|---|
| 22 | font-style: normal; |
|---|
| 23 | } |
|---|
| 24 | body { |
|---|
| 25 | color: black; |
|---|
| 26 | font-family: verdana, helvetica, arial, sans-serif; |
|---|
| 27 | font-size: 10pt; |
|---|
| 28 | } |
|---|
| 29 | cite { |
|---|
| 30 | font-style: normal; |
|---|
| 31 | } |
|---|
| 32 | dd { |
|---|
| 33 | margin-right: 2em; |
|---|
| 34 | } |
|---|
| 35 | dl { |
|---|
| 36 | margin-left: 2em; |
|---|
| 37 | } |
|---|
| 38 | |
|---|
| 39 | dl.empty dd { |
|---|
| 40 | margin-top: .5em; |
|---|
| 41 | } |
|---|
| 42 | dl p { |
|---|
| 43 | margin-left: 0em; |
|---|
| 44 | } |
|---|
| 45 | dt { |
|---|
| 46 | margin-top: .5em; |
|---|
| 47 | } |
|---|
| 48 | h1 { |
|---|
| 49 | font-size: 14pt; |
|---|
| 50 | line-height: 21pt; |
|---|
| 51 | page-break-after: avoid; |
|---|
| 52 | } |
|---|
| 53 | h1.np { |
|---|
| 54 | page-break-before: always; |
|---|
| 55 | } |
|---|
| 56 | h1 a { |
|---|
| 57 | color: #333333; |
|---|
| 58 | } |
|---|
| 59 | h2 { |
|---|
| 60 | font-size: 12pt; |
|---|
| 61 | line-height: 15pt; |
|---|
| 62 | page-break-after: avoid; |
|---|
| 63 | } |
|---|
| 64 | h2 a { |
|---|
| 65 | color: black; |
|---|
| 66 | } |
|---|
| 67 | h3 { |
|---|
| 68 | font-size: 10pt; |
|---|
| 69 | page-break-after: avoid; |
|---|
| 70 | } |
|---|
| 71 | h3 a { |
|---|
| 72 | color: black; |
|---|
| 73 | } |
|---|
| 74 | h4 { |
|---|
| 75 | font-size: 10pt; |
|---|
| 76 | page-break-after: avoid; |
|---|
| 77 | } |
|---|
| 78 | h4 a { |
|---|
| 79 | color: black; |
|---|
| 80 | } |
|---|
| 81 | h5 { |
|---|
| 82 | font-size: 10pt; |
|---|
| 83 | page-break-after: avoid; |
|---|
| 84 | } |
|---|
| 85 | h5 a { |
|---|
| 86 | color: black; |
|---|
| 87 | } |
|---|
| 88 | img { |
|---|
| 89 | margin-left: 3em; |
|---|
| 90 | } |
|---|
| 91 | li { |
|---|
| 92 | margin-left: 2em; |
|---|
| 93 | margin-right: 2em; |
|---|
| 94 | } |
|---|
| 95 | ol { |
|---|
| 96 | margin-left: 2em; |
|---|
| 97 | margin-right: 2em; |
|---|
| 98 | } |
|---|
| 99 | ol p { |
|---|
| 100 | margin-left: 0em; |
|---|
| 101 | } |
|---|
| 102 | p { |
|---|
| 103 | margin-left: 2em; |
|---|
| 104 | margin-right: 2em; |
|---|
| 105 | } |
|---|
| 106 | pre { |
|---|
| 107 | margin-left: 3em; |
|---|
| 108 | background-color: lightyellow; |
|---|
| 109 | padding: .25em; |
|---|
| 110 | } |
|---|
| 111 | pre.text2 { |
|---|
| 112 | border-style: dotted; |
|---|
| 113 | border-width: 1px; |
|---|
| 114 | background-color: #f0f0f0; |
|---|
| 115 | width: 69em; |
|---|
| 116 | } |
|---|
| 117 | pre.inline { |
|---|
| 118 | background-color: white; |
|---|
| 119 | padding: 0em; |
|---|
| 120 | } |
|---|
| 121 | pre.text { |
|---|
| 122 | border-style: dotted; |
|---|
| 123 | border-width: 1px; |
|---|
| 124 | background-color: #f8f8f8; |
|---|
| 125 | width: 69em; |
|---|
| 126 | } |
|---|
| 127 | pre.drawing { |
|---|
| 128 | border-style: solid; |
|---|
| 129 | border-width: 1px; |
|---|
| 130 | background-color: #f8f8f8; |
|---|
| 131 | padding: 2em; |
|---|
| 132 | } |
|---|
| 133 | table { |
|---|
| 134 | margin-left: 2em; |
|---|
| 135 | } |
|---|
| 136 | table.tt { |
|---|
| 137 | vertical-align: top; |
|---|
| 138 | } |
|---|
| 139 | table.full { |
|---|
| 140 | border-style: outset; |
|---|
| 141 | border-width: 1px; |
|---|
| 142 | } |
|---|
| 143 | table.headers { |
|---|
| 144 | border-style: outset; |
|---|
| 145 | border-width: 1px; |
|---|
| 146 | } |
|---|
| 147 | table.tt td { |
|---|
| 148 | vertical-align: top; |
|---|
| 149 | } |
|---|
| 150 | table.full td { |
|---|
| 151 | border-style: inset; |
|---|
| 152 | border-width: 1px; |
|---|
| 153 | } |
|---|
| 154 | table.tt th { |
|---|
| 155 | vertical-align: top; |
|---|
| 156 | } |
|---|
| 157 | table.full th { |
|---|
| 158 | border-style: inset; |
|---|
| 159 | border-width: 1px; |
|---|
| 160 | } |
|---|
| 161 | table.headers th { |
|---|
| 162 | border-style: none none inset none; |
|---|
| 163 | border-width: 1px; |
|---|
| 164 | } |
|---|
| 165 | table.header { |
|---|
| 166 | width: 95%; |
|---|
| 167 | font-size: 10pt; |
|---|
| 168 | color: white; |
|---|
| 169 | } |
|---|
| 170 | td.top { |
|---|
| 171 | vertical-align: top; |
|---|
| 172 | } |
|---|
| 173 | td.topnowrap { |
|---|
| 174 | vertical-align: top; |
|---|
| 175 | white-space: nowrap; |
|---|
| 176 | } |
|---|
| 177 | td.header { |
|---|
| 178 | background-color: gray; |
|---|
| 179 | width: 50%; |
|---|
| 180 | } |
|---|
| 181 | td.header a { |
|---|
| 182 | color: white; |
|---|
| 183 | } |
|---|
| 184 | td.reference { |
|---|
| 185 | vertical-align: top; |
|---|
| 186 | white-space: nowrap; |
|---|
| 187 | padding-right: 1em; |
|---|
| 188 | } |
|---|
| 189 | thead { |
|---|
| 190 | display:table-header-group; |
|---|
| 191 | } |
|---|
| 192 | ul.toc { |
|---|
| 193 | list-style: none; |
|---|
| 194 | margin-left: 1.5em; |
|---|
| 195 | margin-right: 0em; |
|---|
| 196 | padding-left: 0em; |
|---|
| 197 | } |
|---|
| 198 | li.tocline0 { |
|---|
| 199 | line-height: 150%; |
|---|
| 200 | font-weight: bold; |
|---|
| 201 | font-size: 10pt; |
|---|
| 202 | margin-left: 0em; |
|---|
| 203 | margin-right: 0em; |
|---|
| 204 | } |
|---|
| 205 | li.tocline1 { |
|---|
| 206 | line-height: normal; |
|---|
| 207 | font-weight: normal; |
|---|
| 208 | font-size: 9pt; |
|---|
| 209 | margin-left: 0em; |
|---|
| 210 | margin-right: 0em; |
|---|
| 211 | } |
|---|
| 212 | li.tocline2 { |
|---|
| 213 | font-size: 0pt; |
|---|
| 214 | } |
|---|
| 215 | ul p { |
|---|
| 216 | margin-left: 0em; |
|---|
| 217 | } |
|---|
| 218 | ul.ind { |
|---|
| 219 | list-style: none; |
|---|
| 220 | margin-left: 1.5em; |
|---|
| 221 | margin-right: 0em; |
|---|
| 222 | padding-left: 0em; |
|---|
| 223 | } |
|---|
| 224 | li.indline0 { |
|---|
| 225 | font-weight: bold; |
|---|
| 226 | line-height: 200%; |
|---|
| 227 | margin-left: 0em; |
|---|
| 228 | margin-right: 0em; |
|---|
| 229 | } |
|---|
| 230 | li.indline1 { |
|---|
| 231 | font-weight: normal; |
|---|
| 232 | line-height: 150%; |
|---|
| 233 | margin-left: 0em; |
|---|
| 234 | margin-right: 0em; |
|---|
| 235 | } |
|---|
| 236 | .bcp14 { |
|---|
| 237 | font-style: normal; |
|---|
| 238 | text-transform: lowercase; |
|---|
| 239 | font-variant: small-caps; |
|---|
| 240 | } |
|---|
| 241 | .comment { |
|---|
| 242 | background-color: yellow; |
|---|
| 243 | } |
|---|
| 244 | .center { |
|---|
| 245 | text-align: center; |
|---|
| 246 | } |
|---|
| 247 | .error { |
|---|
| 248 | color: red; |
|---|
| 249 | font-style: italic; |
|---|
| 250 | font-weight: bold; |
|---|
| 251 | } |
|---|
| 252 | .figure { |
|---|
| 253 | font-weight: bold; |
|---|
| 254 | text-align: center; |
|---|
| 255 | font-size: 9pt; |
|---|
| 256 | } |
|---|
| 257 | .filename { |
|---|
| 258 | color: #333333; |
|---|
| 259 | font-weight: bold; |
|---|
| 260 | font-size: 12pt; |
|---|
| 261 | line-height: 21pt; |
|---|
| 262 | text-align: center; |
|---|
| 263 | } |
|---|
| 264 | .fn { |
|---|
| 265 | font-weight: bold; |
|---|
| 266 | } |
|---|
| 267 | .hidden { |
|---|
| 268 | display: none; |
|---|
| 269 | } |
|---|
| 270 | .left { |
|---|
| 271 | text-align: left; |
|---|
| 272 | } |
|---|
| 273 | .right { |
|---|
| 274 | text-align: right; |
|---|
| 275 | } |
|---|
| 276 | .title { |
|---|
| 277 | color: #990000; |
|---|
| 278 | font-size: 18pt; |
|---|
| 279 | line-height: 18pt; |
|---|
| 280 | font-weight: bold; |
|---|
| 281 | text-align: center; |
|---|
| 282 | margin-top: 36pt; |
|---|
| 283 | } |
|---|
| 284 | .vcardline { |
|---|
| 285 | display: block; |
|---|
| 286 | } |
|---|
| 287 | .warning { |
|---|
| 288 | font-size: 14pt; |
|---|
| 289 | background-color: yellow; |
|---|
| 290 | } |
|---|
| 291 | |
|---|
| 292 | |
|---|
| 293 | @media print { |
|---|
| 294 | .noprint { |
|---|
| 295 | display: none; |
|---|
| 296 | } |
|---|
| 297 | |
|---|
| 298 | a { |
|---|
| 299 | color: black; |
|---|
| 300 | text-decoration: none; |
|---|
| 301 | } |
|---|
| 302 | |
|---|
| 303 | table.header { |
|---|
| 304 | width: 90%; |
|---|
| 305 | } |
|---|
| 306 | |
|---|
| 307 | td.header { |
|---|
| 308 | width: 50%; |
|---|
| 309 | color: black; |
|---|
| 310 | background-color: white; |
|---|
| 311 | vertical-align: top; |
|---|
| 312 | font-size: 12pt; |
|---|
| 313 | } |
|---|
| 314 | |
|---|
| 315 | ul.toc a::after { |
|---|
| 316 | content: leader('.') target-counter(attr(href), page); |
|---|
| 317 | } |
|---|
| 318 | |
|---|
| 319 | a.iref { |
|---|
| 320 | content: target-counter(attr(href), page); |
|---|
| 321 | } |
|---|
| 322 | |
|---|
| 323 | .print2col { |
|---|
| 324 | column-count: 2; |
|---|
| 325 | -moz-column-count: 2; |
|---|
| 326 | column-fill: auto; |
|---|
| 327 | } |
|---|
| 328 | } |
|---|
| 329 | |
|---|
| 330 | @page { |
|---|
| 331 | @top-left { |
|---|
| 332 | content: "INTERNET DRAFT"; |
|---|
| 333 | } |
|---|
| 334 | @top-right { |
|---|
| 335 | content: "July 2008"; |
|---|
| 336 | } |
|---|
| 337 | @top-center { |
|---|
| 338 | content: "HTTP/1.1, Part 3"; |
|---|
| 339 | } |
|---|
| 340 | @bottom-left { |
|---|
| 341 | content: "Fielding, et al."; |
|---|
| 342 | } |
|---|
| 343 | @bottom-center { |
|---|
| 344 | content: "Standards Track"; |
|---|
| 345 | } |
|---|
| 346 | @bottom-right { |
|---|
| 347 | content: "[Page " counter(page) "]"; |
|---|
| 348 | } |
|---|
| 349 | } |
|---|
| 350 | |
|---|
| 351 | @page:first { |
|---|
| 352 | @top-left { |
|---|
| 353 | content: normal; |
|---|
| 354 | } |
|---|
| 355 | @top-right { |
|---|
| 356 | content: normal; |
|---|
| 357 | } |
|---|
| 358 | @top-center { |
|---|
| 359 | content: normal; |
|---|
| 360 | } |
|---|
| 361 | } |
|---|
| 362 | </style><link rel="Contents" href="#rfc.toc"> |
|---|
| 363 | <link rel="Author" href="#rfc.authors"> |
|---|
| 364 | <link rel="Copyright" href="#rfc.copyright"> |
|---|
| 365 | <link rel="Index" href="#rfc.index"> |
|---|
| 366 | <link rel="Chapter" title="1 Introduction" href="#rfc.section.1"> |
|---|
| 367 | <link rel="Chapter" title="2 Notational Conventions and Generic Grammar" href="#rfc.section.2"> |
|---|
| 368 | <link rel="Chapter" title="3 Protocol Parameters" href="#rfc.section.3"> |
|---|
| 369 | <link rel="Chapter" title="4 Entity" href="#rfc.section.4"> |
|---|
| 370 | <link rel="Chapter" title="5 Content Negotiation" href="#rfc.section.5"> |
|---|
| 371 | <link rel="Chapter" title="6 Header Field Definitions" href="#rfc.section.6"> |
|---|
| 372 | <link rel="Chapter" title="7 IANA Considerations" href="#rfc.section.7"> |
|---|
| 373 | <link rel="Chapter" title="8 Security Considerations" href="#rfc.section.8"> |
|---|
| 374 | <link rel="Chapter" title="9 Acknowledgments" href="#rfc.section.9"> |
|---|
| 375 | <link rel="Chapter" href="#rfc.section.10" title="10 References"> |
|---|
| 376 | <link rel="Appendix" title="A Differences Between HTTP Entities and RFC 2045 Entities" href="#rfc.section.A"> |
|---|
| 377 | <link rel="Appendix" title="B Additional Features" href="#rfc.section.B"> |
|---|
| 378 | <link rel="Appendix" title="C Compatibility with Previous Versions" href="#rfc.section.C"> |
|---|
| 379 | <link rel="Appendix" title="D Change Log (to be removed by RFC Editor before publication)" href="#rfc.section.D"> |
|---|
| 380 | <meta name="generator" content="http://greenbytes.de/tech/webdav/rfc2629.xslt, Revision 1.379, 2008-07-06 13:38:32, XSLT vendor: SAXON 8.9 from Saxonica http://www.saxonica.com/"> |
|---|
| 381 | <link rel="schema.DC" href="http://purl.org/dc/elements/1.1/"> |
|---|
| 382 | <meta name="DC.Creator" content="Fielding, R."> |
|---|
| 383 | <meta name="DC.Creator" content="Gettys, J."> |
|---|
| 384 | <meta name="DC.Creator" content="Mogul, J."> |
|---|
| 385 | <meta name="DC.Creator" content="Frystyk, H."> |
|---|
| 386 | <meta name="DC.Creator" content="Masinter, L."> |
|---|
| 387 | <meta name="DC.Creator" content="Leach, P."> |
|---|
| 388 | <meta name="DC.Creator" content="Berners-Lee, T."> |
|---|
| 389 | <meta name="DC.Creator" content="Lafon, Y."> |
|---|
| 390 | <meta name="DC.Creator" content="Reschke, J. F."> |
|---|
| 391 | <meta name="DC.Identifier" content="urn:ietf:id:draft-ietf-httpbis-p3-payload-latest"> |
|---|
| 392 | <meta name="DC.Date.Issued" scheme="ISO8601" content="2008-07"> |
|---|
| 393 | <meta name="DC.Relation.Replaces" content="urn:ietf:rfc:2616"> |
|---|
| 394 | <meta name="DC.Description.Abstract" content="The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 3 of the seven-part specification that defines the protocol referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616. Part 3 defines HTTP message content, metadata, and content negotiation."> |
|---|
| 395 | </head> |
|---|
| 396 | <body> |
|---|
| 397 | <table summary="header information" class="header" border="0" cellpadding="1" cellspacing="1"> |
|---|
| 398 | <tr> |
|---|
| 399 | <td class="header left">Network Working Group</td> |
|---|
| 400 | <td class="header right">R. Fielding, Editor</td> |
|---|
| 401 | </tr> |
|---|
| 402 | <tr> |
|---|
| 403 | <td class="header left">Internet Draft</td> |
|---|
| 404 | <td class="header right">Day Software</td> |
|---|
| 405 | </tr> |
|---|
| 406 | <tr> |
|---|
| 407 | <td class="header left"> |
|---|
| 408 | <draft-ietf-httpbis-p3-payload-latest> |
|---|
| 409 | |
|---|
| 410 | </td> |
|---|
| 411 | <td class="header right">J. Gettys</td> |
|---|
| 412 | </tr> |
|---|
| 413 | <tr> |
|---|
| 414 | <td class="header left">Obsoletes: <a href="http://tools.ietf.org/html/rfc2616">2616</a> (if approved) |
|---|
| 415 | </td> |
|---|
| 416 | <td class="header right">One Laptop per Child</td> |
|---|
| 417 | </tr> |
|---|
| 418 | <tr> |
|---|
| 419 | <td class="header left">Intended status: Standards Track</td> |
|---|
| 420 | <td class="header right">J. Mogul</td> |
|---|
| 421 | </tr> |
|---|
| 422 | <tr> |
|---|
| 423 | <td class="header left">Expires: January 2009</td> |
|---|
| 424 | <td class="header right">HP</td> |
|---|
| 425 | </tr> |
|---|
| 426 | <tr> |
|---|
| 427 | <td class="header left"></td> |
|---|
| 428 | <td class="header right">H. Frystyk</td> |
|---|
| 429 | </tr> |
|---|
| 430 | <tr> |
|---|
| 431 | <td class="header left"></td> |
|---|
| 432 | <td class="header right">Microsoft</td> |
|---|
| 433 | </tr> |
|---|
| 434 | <tr> |
|---|
| 435 | <td class="header left"></td> |
|---|
| 436 | <td class="header right">L. Masinter</td> |
|---|
| 437 | </tr> |
|---|
| 438 | <tr> |
|---|
| 439 | <td class="header left"></td> |
|---|
| 440 | <td class="header right">Adobe Systems</td> |
|---|
| 441 | </tr> |
|---|
| 442 | <tr> |
|---|
| 443 | <td class="header left"></td> |
|---|
| 444 | <td class="header right">P. Leach</td> |
|---|
| 445 | </tr> |
|---|
| 446 | <tr> |
|---|
| 447 | <td class="header left"></td> |
|---|
| 448 | <td class="header right">Microsoft</td> |
|---|
| 449 | </tr> |
|---|
| 450 | <tr> |
|---|
| 451 | <td class="header left"></td> |
|---|
| 452 | <td class="header right">T. Berners-Lee</td> |
|---|
| 453 | </tr> |
|---|
| 454 | <tr> |
|---|
| 455 | <td class="header left"></td> |
|---|
| 456 | <td class="header right">W3C/MIT</td> |
|---|
| 457 | </tr> |
|---|
| 458 | <tr> |
|---|
| 459 | <td class="header left"></td> |
|---|
| 460 | <td class="header right">Y. Lafon, Editor</td> |
|---|
| 461 | </tr> |
|---|
| 462 | <tr> |
|---|
| 463 | <td class="header left"></td> |
|---|
| 464 | <td class="header right">W3C</td> |
|---|
| 465 | </tr> |
|---|
| 466 | <tr> |
|---|
| 467 | <td class="header left"></td> |
|---|
| 468 | <td class="header right">J. F. Reschke, Editor</td> |
|---|
| 469 | </tr> |
|---|
| 470 | <tr> |
|---|
| 471 | <td class="header left"></td> |
|---|
| 472 | <td class="header right">greenbytes</td> |
|---|
| 473 | </tr> |
|---|
| 474 | <tr> |
|---|
| 475 | <td class="header left"></td> |
|---|
| 476 | <td class="header right">July 6, 2008</td> |
|---|
| 477 | </tr> |
|---|
| 478 | </table> |
|---|
| 479 | <p class="title">HTTP/1.1, part 3: Message Payload and Content Negotiation<br><span class="filename">draft-ietf-httpbis-p3-payload-latest</span></p> |
|---|
| 480 | <h1><a id="rfc.status" href="#rfc.status">Status of this Memo</a></h1> |
|---|
| 481 | <p>By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she |
|---|
| 482 | is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section |
|---|
| 483 | 6 of BCP 79. |
|---|
| 484 | </p> |
|---|
| 485 | <p>Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note |
|---|
| 486 | that other groups may also distribute working documents as Internet-Drafts. |
|---|
| 487 | </p> |
|---|
| 488 | <p>Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other |
|---|
| 489 | documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as “work |
|---|
| 490 | in progress”. |
|---|
| 491 | </p> |
|---|
| 492 | <p>The list of current Internet-Drafts can be accessed at <<a href="http://www.ietf.org/ietf/1id-abstracts.txt">http://www.ietf.org/ietf/1id-abstracts.txt</a>>. |
|---|
| 493 | </p> |
|---|
| 494 | <p>The list of Internet-Draft Shadow Directories can be accessed at <<a href="http://www.ietf.org/shadow.html">http://www.ietf.org/shadow.html</a>>. |
|---|
| 495 | </p> |
|---|
| 496 | <p>This Internet-Draft will expire in January 2009.</p> |
|---|
| 497 | <h1 id="rfc.abstract"><a href="#rfc.abstract">Abstract</a></h1> |
|---|
| 498 | <p>The Hypertext Transfer Protocol (HTTP) is an application-level protocol for distributed, collaborative, hypermedia information |
|---|
| 499 | systems. HTTP has been in use by the World Wide Web global information initiative since 1990. This document is Part 3 of the |
|---|
| 500 | seven-part specification that defines the protocol referred to as "HTTP/1.1" and, taken together, obsoletes RFC 2616. Part |
|---|
| 501 | 3 defines HTTP message content, metadata, and content negotiation. |
|---|
| 502 | </p> |
|---|
| 503 | <h1 id="rfc.note.1"><a href="#rfc.note.1">Editorial Note (To be removed by RFC Editor)</a></h1> |
|---|
| 504 | <p>Discussion of this draft should take place on the HTTPBIS working group mailing list (ietf-http-wg@w3.org). The current issues |
|---|
| 505 | list is at <<a href="http://www.tools.ietf.org/wg/httpbis/trac/report/11">http://www.tools.ietf.org/wg/httpbis/trac/report/11</a>> and related documents (including fancy diffs) can be found at <<a href="http://www.tools.ietf.org/wg/httpbis/">http://www.tools.ietf.org/wg/httpbis/</a>>. |
|---|
| 506 | </p> |
|---|
| 507 | <p>The changes in this draft are summarized in <a href="#changes.since.02" title="Since draft-ietf-httpbis-p3-payload-02">Appendix D.4</a>. |
|---|
| 508 | </p> |
|---|
| 509 | <hr class="noprint"> |
|---|
| 510 | <h1 class="np" id="rfc.toc"><a href="#rfc.toc">Table of Contents</a></h1> |
|---|
| 511 | <ul class="toc"> |
|---|
| 512 | <li class="tocline0">1. <a href="#introduction">Introduction</a><ul class="toc"> |
|---|
| 513 | <li class="tocline1">1.1 <a href="#intro.requirements">Requirements</a></li> |
|---|
| 514 | </ul> |
|---|
| 515 | </li> |
|---|
| 516 | <li class="tocline0">2. <a href="#notation">Notational Conventions and Generic Grammar</a></li> |
|---|
| 517 | <li class="tocline0">3. <a href="#protocol.parameters">Protocol Parameters</a><ul class="toc"> |
|---|
| 518 | <li class="tocline1">3.1 <a href="#character.sets">Character Sets</a><ul class="toc"> |
|---|
| 519 | <li class="tocline1">3.1.1 <a href="#missing.charset">Missing Charset</a></li> |
|---|
| 520 | </ul> |
|---|
| 521 | </li> |
|---|
| 522 | <li class="tocline1">3.2 <a href="#content.codings">Content Codings</a></li> |
|---|
| 523 | <li class="tocline1">3.3 <a href="#media.types">Media Types</a><ul class="toc"> |
|---|
| 524 | <li class="tocline1">3.3.1 <a href="#canonicalization.and.text.defaults">Canonicalization and Text Defaults</a></li> |
|---|
| 525 | <li class="tocline1">3.3.2 <a href="#multipart.types">Multipart Types</a></li> |
|---|
| 526 | </ul> |
|---|
| 527 | </li> |
|---|
| 528 | <li class="tocline1">3.4 <a href="#quality.values">Quality Values</a></li> |
|---|
| 529 | <li class="tocline1">3.5 <a href="#language.tags">Language Tags</a></li> |
|---|
| 530 | </ul> |
|---|
| 531 | </li> |
|---|
| 532 | <li class="tocline0">4. <a href="#entity">Entity</a><ul class="toc"> |
|---|
| 533 | <li class="tocline1">4.1 <a href="#entity.header.fields">Entity Header Fields</a></li> |
|---|
| 534 | <li class="tocline1">4.2 <a href="#entity.body">Entity Body</a><ul class="toc"> |
|---|
| 535 | <li class="tocline1">4.2.1 <a href="#type">Type</a></li> |
|---|
| 536 | <li class="tocline1">4.2.2 <a href="#entity.length">Entity Length</a></li> |
|---|
| 537 | </ul> |
|---|
| 538 | </li> |
|---|
| 539 | </ul> |
|---|
| 540 | </li> |
|---|
| 541 | <li class="tocline0">5. <a href="#content.negotiation">Content Negotiation</a><ul class="toc"> |
|---|
| 542 | <li class="tocline1">5.1 <a href="#server-driven.negotiation">Server-driven Negotiation</a></li> |
|---|
| 543 | <li class="tocline1">5.2 <a href="#agent-driven.negotiation">Agent-driven Negotiation</a></li> |
|---|
| 544 | <li class="tocline1">5.3 <a href="#transparent.negotiation">Transparent Negotiation</a></li> |
|---|
| 545 | </ul> |
|---|
| 546 | </li> |
|---|
| 547 | <li class="tocline0">6. <a href="#header.fields">Header Field Definitions</a><ul class="toc"> |
|---|
| 548 | <li class="tocline1">6.1 <a href="#header.accept">Accept</a></li> |
|---|
| 549 | <li class="tocline1">6.2 <a href="#header.accept-charset">Accept-Charset</a></li> |
|---|
| 550 | <li class="tocline1">6.3 <a href="#header.accept-encoding">Accept-Encoding</a></li> |
|---|
| 551 | <li class="tocline1">6.4 <a href="#header.accept-language">Accept-Language</a></li> |
|---|
| 552 | <li class="tocline1">6.5 <a href="#header.content-encoding">Content-Encoding</a></li> |
|---|
| 553 | <li class="tocline1">6.6 <a href="#header.content-language">Content-Language</a></li> |
|---|
| 554 | <li class="tocline1">6.7 <a href="#header.content-location">Content-Location</a></li> |
|---|
| 555 | <li class="tocline1">6.8 <a href="#header.content-md5">Content-MD5</a></li> |
|---|
| 556 | <li class="tocline1">6.9 <a href="#header.content-type">Content-Type</a></li> |
|---|
| 557 | </ul> |
|---|
| 558 | </li> |
|---|
| 559 | <li class="tocline0">7. <a href="#IANA.considerations">IANA Considerations</a><ul class="toc"> |
|---|
| 560 | <li class="tocline1">7.1 <a href="#message.header.registration">Message Header Registration</a></li> |
|---|
| 561 | </ul> |
|---|
| 562 | </li> |
|---|
| 563 | <li class="tocline0">8. <a href="#security.considerations">Security Considerations</a><ul class="toc"> |
|---|
| 564 | <li class="tocline1">8.1 <a href="#privacy.issues.connected.to.accept.headers">Privacy Issues Connected to Accept Headers</a></li> |
|---|
| 565 | <li class="tocline1">8.2 <a href="#content-disposition.issues">Content-Disposition Issues</a></li> |
|---|
| 566 | </ul> |
|---|
| 567 | </li> |
|---|
| 568 | <li class="tocline0">9. <a href="#ack">Acknowledgments</a></li> |
|---|
| 569 | <li class="tocline0">10. <a href="#rfc.references">References</a><ul class="toc"> |
|---|
| 570 | <li class="tocline1">10.1 <a href="#rfc.references.1">Normative References</a></li> |
|---|
| 571 | <li class="tocline1">10.2 <a href="#rfc.references.2">Informative References</a></li> |
|---|
| 572 | </ul> |
|---|
| 573 | </li> |
|---|
| 574 | <li class="tocline0"><a href="#rfc.authors">Authors' Addresses</a></li> |
|---|
| 575 | <li class="tocline0">A. <a href="#differences.between.http.entities.and.rfc.2045.entities">Differences Between HTTP Entities and RFC 2045 Entities</a><ul class="toc"> |
|---|
| 576 | <li class="tocline1">A.1 <a href="#mime-version">MIME-Version</a></li> |
|---|
| 577 | <li class="tocline1">A.2 <a href="#conversion.to.canonical.form">Conversion to Canonical Form</a></li> |
|---|
| 578 | <li class="tocline1">A.3 <a href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></li> |
|---|
| 579 | <li class="tocline1">A.4 <a href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></li> |
|---|
| 580 | <li class="tocline1">A.5 <a href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></li> |
|---|
| 581 | <li class="tocline1">A.6 <a href="#mhtml.line.length">MHTML and Line Length Limitations</a></li> |
|---|
| 582 | </ul> |
|---|
| 583 | </li> |
|---|
| 584 | <li class="tocline0">B. <a href="#additional.features">Additional Features</a><ul class="toc"> |
|---|
| 585 | <li class="tocline1">B.1 <a href="#content-disposition">Content-Disposition</a></li> |
|---|
| 586 | </ul> |
|---|
| 587 | </li> |
|---|
| 588 | <li class="tocline0">C. <a href="#compatibility">Compatibility with Previous Versions</a><ul class="toc"> |
|---|
| 589 | <li class="tocline1">C.1 <a href="#changes.from.rfc.2068">Changes from RFC 2068</a></li> |
|---|
| 590 | <li class="tocline1">C.2 <a href="#changes.from.rfc.2616">Changes from RFC 2616</a></li> |
|---|
| 591 | </ul> |
|---|
| 592 | </li> |
|---|
| 593 | <li class="tocline0">D. <a href="#change.log">Change Log (to be removed by RFC Editor before publication)</a><ul class="toc"> |
|---|
| 594 | <li class="tocline1">D.1 <a href="#rfc.section.D.1">Since RFC2616</a></li> |
|---|
| 595 | <li class="tocline1">D.2 <a href="#rfc.section.D.2">Since draft-ietf-httpbis-p3-payload-00</a></li> |
|---|
| 596 | <li class="tocline1">D.3 <a href="#rfc.section.D.3">Since draft-ietf-httpbis-p3-payload-01</a></li> |
|---|
| 597 | <li class="tocline1">D.4 <a href="#changes.since.02">Since draft-ietf-httpbis-p3-payload-02</a></li> |
|---|
| 598 | <li class="tocline1">D.5 <a href="#changes.since.03">Since draft-ietf-httpbis-p3-payload-03</a></li> |
|---|
| 599 | </ul> |
|---|
| 600 | </li> |
|---|
| 601 | <li class="tocline0"><a href="#rfc.ipr">Intellectual Property and Copyright Statements</a></li> |
|---|
| 602 | <li class="tocline0"><a href="#rfc.index">Index</a></li> |
|---|
| 603 | </ul> |
|---|
| 604 | <h1 id="rfc.section.1" class="np"><a href="#rfc.section.1">1.</a> <a id="introduction" href="#introduction">Introduction</a></h1> |
|---|
| 605 | <p id="rfc.section.1.p.1">This document defines HTTP/1.1 message payloads (a.k.a., content), the associated metadata header fields that define how the |
|---|
| 606 | payload is intended to be interpreted by a recipient, the request header fields that may influence content selection, and |
|---|
| 607 | the various selection algorithms that are collectively referred to as HTTP content negotiation. |
|---|
| 608 | </p> |
|---|
| 609 | <p id="rfc.section.1.p.2">This document is currently disorganized in order to minimize the changes between drafts and enable reviewers to see the smaller |
|---|
| 610 | errata changes. The next draft will reorganize the sections to better reflect the content. In particular, the sections on |
|---|
| 611 | entities will be renamed payload and moved to the first half of the document, while the sections on content negotiation and |
|---|
| 612 | associated request header fields will be moved to the second half. The current mess reflects how widely dispersed these topics |
|---|
| 613 | and associated requirements had become in <a href="#RFC2616" id="rfc.xref.RFC2616.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>. |
|---|
| 614 | </p> |
|---|
| 615 | <h2 id="rfc.section.1.1"><a href="#rfc.section.1.1">1.1</a> <a id="intro.requirements" href="#intro.requirements">Requirements</a></h2> |
|---|
| 616 | <p id="rfc.section.1.1.p.1">The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" |
|---|
| 617 | in this document are to be interpreted as described in <a href="#RFC2119" id="rfc.xref.RFC2119.1"><cite title="Key words for use in RFCs to Indicate Requirement Levels">[RFC2119]</cite></a>. |
|---|
| 618 | </p> |
|---|
| 619 | <p id="rfc.section.1.1.p.2">An implementation is not compliant if it fails to satisfy one or more of the <em class="bcp14">MUST</em> or <em class="bcp14">REQUIRED</em> level requirements for the protocols it implements. An implementation that satisfies all the <em class="bcp14">MUST</em> or <em class="bcp14">REQUIRED</em> level and all the <em class="bcp14">SHOULD</em> level requirements for its protocols is said to be "unconditionally compliant"; one that satisfies all the <em class="bcp14">MUST</em> level requirements but not all the <em class="bcp14">SHOULD</em> level requirements for its protocols is said to be "conditionally compliant." |
|---|
| 620 | </p> |
|---|
| 621 | <h1 id="rfc.section.2"><a href="#rfc.section.2">2.</a> <a id="notation" href="#notation">Notational Conventions and Generic Grammar</a></h1> |
|---|
| 622 | <p id="rfc.section.2.p.1">This specification uses the ABNF syntax defined in <a href="p1-messaging.html#notation.abnf" title="Augmented BNF">Section 2.1</a> of <a href="#Part1" id="rfc.xref.Part1.1"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> and the core rules defined in <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 2.2</a> of <a href="#Part1" id="rfc.xref.Part1.2"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>: <span class="comment">[abnf.dep: ABNF syntax and basic rules will be adopted from RFC 5234, see <<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/36">http://tools.ietf.org/wg/httpbis/trac/ticket/36</a>>.]</span> |
|---|
| 623 | </p> |
|---|
| 624 | <div id="rfc.figure.u.1"></div><pre class="inline"> <a href="#notation" class="smpl">ALPHA</a> = <ALPHA, defined in <a href="#Part1" id="rfc.xref.Part1.3"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 2.2</a>> |
|---|
| 625 | <a href="#notation" class="smpl">DIGIT</a> = <DIGIT, defined in <a href="#Part1" id="rfc.xref.Part1.4"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 2.2</a>> |
|---|
| 626 | <a href="#notation" class="smpl">OCTET</a> = <OCTET, defined in <a href="#Part1" id="rfc.xref.Part1.5"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 2.2</a>> |
|---|
| 627 | </pre><div id="rfc.figure.u.2"></div><pre class="inline"> <a href="#notation" class="smpl">quoted-string</a> = <quoted-string, defined in <a href="#Part1" id="rfc.xref.Part1.6"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 2.2</a>> |
|---|
| 628 | <a href="#notation" class="smpl">token</a> = <token, defined in <a href="#Part1" id="rfc.xref.Part1.7"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#basic.rules" title="Basic Rules">Section 2.2</a>> |
|---|
| 629 | </pre><div id="abnf.dependencies"> |
|---|
| 630 | <p id="rfc.section.2.p.4"> The ABNF rules below are defined in other parts:</p> |
|---|
| 631 | </div> |
|---|
| 632 | <div id="rfc.figure.u.3"></div><pre class="inline"> <a href="#abnf.dependencies" class="smpl">absoluteURI</a> = <absoluteURI, defined in <a href="#Part1" id="rfc.xref.Part1.8"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#general.syntax" title="General Syntax">Section 3.2.1</a>> |
|---|
| 633 | <a href="#abnf.dependencies" class="smpl">Content-Length</a> = <Content-Length, defined in <a href="#Part1" id="rfc.xref.Part1.9"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#header.content-length" title="Content-Length">Section 8.2</a>> |
|---|
| 634 | <a href="#abnf.dependencies" class="smpl">relativeURI</a> = <relativeURI, defined in <a href="#Part1" id="rfc.xref.Part1.10"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#general.syntax" title="General Syntax">Section 3.2.1</a>> |
|---|
| 635 | <a href="#abnf.dependencies" class="smpl">message-header</a> = <message-header, defined in <a href="#Part1" id="rfc.xref.Part1.11"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#message.headers" title="Message Headers">Section 4.2</a>> |
|---|
| 636 | </pre><div id="rfc.figure.u.4"></div><pre class="inline"> <a href="#abnf.dependencies" class="smpl">Last-Modified</a> = <Last-Modified, defined in <a href="#Part4" id="rfc.xref.Part4.1"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>, <a href="p4-conditional.html#header.last-modified" title="Last-Modified">Section 7.6</a>> |
|---|
| 637 | </pre><div id="rfc.figure.u.5"></div><pre class="inline"> <a href="#abnf.dependencies" class="smpl">Content-Range</a> = <Content-Range, defined in <a href="#Part5" id="rfc.xref.Part5.1"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>, <a href="p5-range.html#header.content-range" title="Content-Range">Section 6.2</a>> |
|---|
| 638 | </pre><div id="rfc.figure.u.6"></div><pre class="inline"> <a href="#abnf.dependencies" class="smpl">Expires</a> = <Expires, defined in <a href="#Part6" id="rfc.xref.Part6.1"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.expires" title="Expires">Section 16.3</a>> |
|---|
| 639 | </pre><h1 id="rfc.section.3"><a href="#rfc.section.3">3.</a> <a id="protocol.parameters" href="#protocol.parameters">Protocol Parameters</a></h1> |
|---|
| 640 | <h2 id="rfc.section.3.1"><a href="#rfc.section.3.1">3.1</a> <a id="character.sets" href="#character.sets">Character Sets</a></h2> |
|---|
| 641 | <p id="rfc.section.3.1.p.1">HTTP uses the same definition of the term "character set" as that described for MIME:</p> |
|---|
| 642 | <p id="rfc.section.3.1.p.2">The term "character set" is used in this document to refer to a method used with one or more tables to convert a sequence |
|---|
| 643 | of octets into a sequence of characters. Note that unconditional conversion in the other direction is not required, in that |
|---|
| 644 | not all characters may be available in a given character set and a character set may provide more than one sequence of octets |
|---|
| 645 | to represent a particular character. This definition is intended to allow various kinds of character encoding, from simple |
|---|
| 646 | single-table mappings such as US-ASCII to complex table switching methods such as those that use ISO-2022's techniques. However, |
|---|
| 647 | the definition associated with a MIME character set name <em class="bcp14">MUST</em> fully specify the mapping to be performed from octets to characters. In particular, use of external profiling information |
|---|
| 648 | to determine the exact mapping is not permitted. |
|---|
| 649 | </p> |
|---|
| 650 | <dl class="empty"> |
|---|
| 651 | <dd> <b>Note:</b> This use of the term "character set" is more commonly referred to as a "character encoding." However, since HTTP and MIME |
|---|
| 652 | share the same registry, it is important that the terminology also be shared. |
|---|
| 653 | </dd> |
|---|
| 654 | </dl> |
|---|
| 655 | <div id="rule.charset"> |
|---|
| 656 | <p id="rfc.section.3.1.p.4"> HTTP character sets are identified by case-insensitive tokens. The complete set of tokens is defined by the IANA Character |
|---|
| 657 | Set registry (<<a href="http://www.iana.org/assignments/character-sets">http://www.iana.org/assignments/character-sets</a>>). |
|---|
| 658 | </p> |
|---|
| 659 | </div> |
|---|
| 660 | <div id="rfc.figure.u.7"></div><pre class="inline"><span id="rfc.iref.g.1"></span> <a href="#rule.charset" class="smpl">charset</a> = <a href="#notation" class="smpl">token</a> |
|---|
| 661 | </pre><p id="rfc.section.3.1.p.6">Although HTTP allows an arbitrary token to be used as a charset value, any token that has a predefined value within the IANA |
|---|
| 662 | Character Set registry <em class="bcp14">MUST</em> represent the character set defined by that registry. Applications <em class="bcp14">SHOULD</em> limit their use of character sets to those defined by the IANA registry. |
|---|
| 663 | </p> |
|---|
| 664 | <p id="rfc.section.3.1.p.7">HTTP uses charset in two contexts: within an Accept-Charset request header (in which the charset value is an unquoted token) |
|---|
| 665 | and as the value of a parameter in a Content-Type header (within a request or response), in which case the parameter value |
|---|
| 666 | of the charset parameter may be quoted. |
|---|
| 667 | </p> |
|---|
| 668 | <p id="rfc.section.3.1.p.8">Implementors should be aware of IETF character set requirements <a href="#RFC3629" id="rfc.xref.RFC3629.1"><cite title="UTF-8, a transformation format of ISO 10646">[RFC3629]</cite></a> <a href="#RFC2277" id="rfc.xref.RFC2277.1"><cite title="IETF Policy on Character Sets and Languages">[RFC2277]</cite></a>. |
|---|
| 669 | </p> |
|---|
| 670 | <h3 id="rfc.section.3.1.1"><a href="#rfc.section.3.1.1">3.1.1</a> <a id="missing.charset" href="#missing.charset">Missing Charset</a></h3> |
|---|
| 671 | <p id="rfc.section.3.1.1.p.1">Some HTTP/1.0 software has interpreted a Content-Type header without charset parameter incorrectly to mean "recipient should |
|---|
| 672 | guess." Senders wishing to defeat this behavior <em class="bcp14">MAY</em> include a charset parameter even when the charset is ISO-8859-1 (<a href="#ISO-8859-1" id="rfc.xref.ISO-8859-1.1"><cite title="Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1">[ISO-8859-1]</cite></a>) and <em class="bcp14">SHOULD</em> do so when it is known that it will not confuse the recipient. |
|---|
| 673 | </p> |
|---|
| 674 | <p id="rfc.section.3.1.1.p.2">Unfortunately, some older HTTP/1.0 clients did not deal properly with an explicit charset parameter. HTTP/1.1 recipients <em class="bcp14">MUST</em> respect the charset label provided by the sender; and those user agents that have a provision to "guess" a charset <em class="bcp14">MUST</em> use the charset from the content-type field if they support that charset, rather than the recipient's preference, when initially |
|---|
| 675 | displaying a document. See <a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Section 3.3.1</a>. |
|---|
| 676 | </p> |
|---|
| 677 | <h2 id="rfc.section.3.2"><a href="#rfc.section.3.2">3.2</a> <a id="content.codings" href="#content.codings">Content Codings</a></h2> |
|---|
| 678 | <p id="rfc.section.3.2.p.1">Content coding values indicate an encoding transformation that has been or can be applied to an entity. Content codings are |
|---|
| 679 | primarily used to allow a document to be compressed or otherwise usefully transformed without losing the identity of its underlying |
|---|
| 680 | media type and without loss of information. Frequently, the entity is stored in coded form, transmitted directly, and only |
|---|
| 681 | decoded by the recipient. |
|---|
| 682 | </p> |
|---|
| 683 | <div id="rfc.figure.u.8"></div><pre class="inline"><span id="rfc.iref.g.2"></span> <a href="#content.codings" class="smpl">content-coding</a> = <a href="#notation" class="smpl">token</a> |
|---|
| 684 | </pre><p id="rfc.section.3.2.p.3">All content-coding values are case-insensitive. HTTP/1.1 uses content-coding values in the Accept-Encoding (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.1" title="Accept-Encoding">Section 6.3</a>) and Content-Encoding (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.1" title="Content-Encoding">Section 6.5</a>) header fields. Although the value describes the content-coding, what is more important is that it indicates what decoding |
|---|
| 685 | mechanism will be required to remove the encoding. |
|---|
| 686 | </p> |
|---|
| 687 | <p id="rfc.section.3.2.p.4">The Internet Assigned Numbers Authority (IANA) acts as a registry for content-coding value tokens. Initially, the registry |
|---|
| 688 | contains the following tokens: |
|---|
| 689 | </p> |
|---|
| 690 | <p id="rfc.section.3.2.p.5">gzip<span id="rfc.iref.g.3"></span> |
|---|
| 691 | </p> |
|---|
| 692 | <dl class="empty"> |
|---|
| 693 | <dd>An encoding format produced by the file compression program "gzip" (GNU zip) as described in <a href="#RFC1952" id="rfc.xref.RFC1952.1"><cite title="GZIP file format specification version 4.3">[RFC1952]</cite></a>. This format is a Lempel-Ziv coding (LZ77) with a 32 bit CRC. |
|---|
| 694 | </dd> |
|---|
| 695 | </dl> |
|---|
| 696 | <p id="rfc.section.3.2.p.6">compress<span id="rfc.iref.c.1"></span> |
|---|
| 697 | </p> |
|---|
| 698 | <dl class="empty"> |
|---|
| 699 | <dd>The encoding format produced by the common UNIX file compression program "compress". This format is an adaptive Lempel-Ziv-Welch |
|---|
| 700 | coding (LZW). |
|---|
| 701 | </dd> |
|---|
| 702 | <dd>Use of program names for the identification of encoding formats is not desirable and is discouraged for future encodings. |
|---|
| 703 | Their use here is representative of historical practice, not good design. For compatibility with previous implementations |
|---|
| 704 | of HTTP, applications <em class="bcp14">SHOULD</em> consider "x-gzip" and "x-compress" to be equivalent to "gzip" and "compress" respectively. |
|---|
| 705 | </dd> |
|---|
| 706 | </dl> |
|---|
| 707 | <p id="rfc.section.3.2.p.7">deflate<span id="rfc.iref.d.1"></span> |
|---|
| 708 | </p> |
|---|
| 709 | <dl class="empty"> |
|---|
| 710 | <dd>The "zlib" format defined in <a href="#RFC1950" id="rfc.xref.RFC1950.1"><cite title="ZLIB Compressed Data Format Specification version 3.3">[RFC1950]</cite></a> in combination with the "deflate" compression mechanism described in <a href="#RFC1951" id="rfc.xref.RFC1951.1"><cite title="DEFLATE Compressed Data Format Specification version 1.3">[RFC1951]</cite></a>. |
|---|
| 711 | </dd> |
|---|
| 712 | </dl> |
|---|
| 713 | <p id="rfc.section.3.2.p.8">identity<span id="rfc.iref.i.1"></span> |
|---|
| 714 | </p> |
|---|
| 715 | <dl class="empty"> |
|---|
| 716 | <dd>The default (identity) encoding; the use of no transformation whatsoever. This content-coding is used only in the Accept-Encoding |
|---|
| 717 | header, and <em class="bcp14">SHOULD NOT</em> be used in the Content-Encoding header. |
|---|
| 718 | </dd> |
|---|
| 719 | </dl> |
|---|
| 720 | <p id="rfc.section.3.2.p.9">New content-coding value tokens <em class="bcp14">SHOULD</em> be registered; to allow interoperability between clients and servers, specifications of the content coding algorithms needed |
|---|
| 721 | to implement a new value <em class="bcp14">SHOULD</em> be publicly available and adequate for independent implementation, and conform to the purpose of content coding defined in |
|---|
| 722 | this section. |
|---|
| 723 | </p> |
|---|
| 724 | <h2 id="rfc.section.3.3"><a href="#rfc.section.3.3">3.3</a> <a id="media.types" href="#media.types">Media Types</a></h2> |
|---|
| 725 | <p id="rfc.section.3.3.p.1">HTTP uses Internet Media Types <a href="#RFC2046" id="rfc.xref.RFC2046.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> in the Content-Type (<a href="#header.content-type" id="rfc.xref.header.content-type.1" title="Content-Type">Section 6.9</a>) and Accept (<a href="#header.accept" id="rfc.xref.header.accept.1" title="Accept">Section 6.1</a>) header fields in order to provide open and extensible data typing and type negotiation. |
|---|
| 726 | </p> |
|---|
| 727 | <div id="rfc.figure.u.9"></div><pre class="inline"><span id="rfc.iref.g.4"></span><span id="rfc.iref.g.5"></span><span id="rfc.iref.g.6"></span> <a href="#media.types" class="smpl">media-type</a> = <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> *( ";" <a href="#rule.parameter" class="smpl">parameter</a> ) |
|---|
| 728 | <a href="#media.types" class="smpl">type</a> = <a href="#notation" class="smpl">token</a> |
|---|
| 729 | <a href="#media.types" class="smpl">subtype</a> = <a href="#notation" class="smpl">token</a> |
|---|
| 730 | </pre><div id="rule.parameter"> |
|---|
| 731 | <p id="rfc.section.3.3.p.3"> Parameters <em class="bcp14">MAY</em> follow the type/subtype in the form of attribute/value pairs. |
|---|
| 732 | </p> |
|---|
| 733 | </div> |
|---|
| 734 | <div id="rfc.figure.u.10"></div><pre class="inline"><span id="rfc.iref.g.7"></span><span id="rfc.iref.g.8"></span><span id="rfc.iref.g.9"></span> <a href="#rule.parameter" class="smpl">parameter</a> = <a href="#rule.parameter" class="smpl">attribute</a> "=" <a href="#rule.parameter" class="smpl">value</a> |
|---|
| 735 | <a href="#rule.parameter" class="smpl">attribute</a> = <a href="#notation" class="smpl">token</a> |
|---|
| 736 | <a href="#rule.parameter" class="smpl">value</a> = <a href="#notation" class="smpl">token</a> | <a href="#notation" class="smpl">quoted-string</a> |
|---|
| 737 | </pre><p id="rfc.section.3.3.p.5">The type, subtype, and parameter attribute names are case-insensitive. Parameter values might or might not be case-sensitive, |
|---|
| 738 | depending on the semantics of the parameter name. Linear white space (LWS) <em class="bcp14">MUST NOT</em> be used between the type and subtype, nor between an attribute and its value. The presence or absence of a parameter might |
|---|
| 739 | be significant to the processing of a media-type, depending on its definition within the media type registry. |
|---|
| 740 | </p> |
|---|
| 741 | <p id="rfc.section.3.3.p.6">All parameters defined as a token are also allowed to occur as quoted-string; both notations are equivalent.</p> |
|---|
| 742 | <p id="rfc.section.3.3.p.7">Note that some older HTTP applications do not recognize media type parameters. When sending data to older HTTP applications, |
|---|
| 743 | implementations <em class="bcp14">SHOULD</em> only use media type parameters when they are required by that type/subtype definition. |
|---|
| 744 | </p> |
|---|
| 745 | <p id="rfc.section.3.3.p.8">Media-type values are registered with the Internet Assigned Number Authority (IANA). The media type registration process is |
|---|
| 746 | outlined in <a href="#RFC4288" id="rfc.xref.RFC4288.1"><cite title="Media Type Specifications and Registration Procedures">[RFC4288]</cite></a>. Use of non-registered media types is discouraged. |
|---|
| 747 | </p> |
|---|
| 748 | <h3 id="rfc.section.3.3.1"><a href="#rfc.section.3.3.1">3.3.1</a> <a id="canonicalization.and.text.defaults" href="#canonicalization.and.text.defaults">Canonicalization and Text Defaults</a></h3> |
|---|
| 749 | <p id="rfc.section.3.3.1.p.1">Internet media types are registered with a canonical form. An entity-body transferred via HTTP messages <em class="bcp14">MUST</em> be represented in the appropriate canonical form prior to its transmission except for "text" types, as defined in the next |
|---|
| 750 | paragraph. |
|---|
| 751 | </p> |
|---|
| 752 | <p id="rfc.section.3.3.1.p.2">When in canonical form, media subtypes of the "text" type use CRLF as the text line break. HTTP relaxes this requirement and |
|---|
| 753 | allows the transport of text media with plain CR or LF alone representing a line break when it is done consistently for an |
|---|
| 754 | entire entity-body. HTTP applications <em class="bcp14">MUST</em> accept CRLF, bare CR, and bare LF as being representative of a line break in text media received via HTTP. In addition, if |
|---|
| 755 | the text is represented in a character set that does not use octets 13 and 10 for CR and LF respectively, as is the case for |
|---|
| 756 | some multi-byte character sets, HTTP allows the use of whatever octet sequences are defined by that character set to represent |
|---|
| 757 | the equivalent of CR and LF for line breaks. This flexibility regarding line breaks applies only to text media in the entity-body; |
|---|
| 758 | a bare CR or LF <em class="bcp14">MUST NOT</em> be substituted for CRLF within any of the HTTP control structures (such as header fields and multipart boundaries). |
|---|
| 759 | </p> |
|---|
| 760 | <p id="rfc.section.3.3.1.p.3">If an entity-body is encoded with a content-coding, the underlying data <em class="bcp14">MUST</em> be in a form defined above prior to being encoded. |
|---|
| 761 | </p> |
|---|
| 762 | <p id="rfc.section.3.3.1.p.4">The "charset" parameter is used with some media types to define the character set (<a href="#character.sets" title="Character Sets">Section 3.1</a>) of the data. When no explicit charset parameter is provided by the sender, media subtypes of the "text" type are defined |
|---|
| 763 | to have a default charset value of "ISO-8859-1" when received via HTTP. Data in character sets other than "ISO-8859-1" or |
|---|
| 764 | its subsets <em class="bcp14">MUST</em> be labeled with an appropriate charset value. See <a href="#missing.charset" title="Missing Charset">Section 3.1.1</a> for compatibility problems. |
|---|
| 765 | </p> |
|---|
| 766 | <h3 id="rfc.section.3.3.2"><a href="#rfc.section.3.3.2">3.3.2</a> <a id="multipart.types" href="#multipart.types">Multipart Types</a></h3> |
|---|
| 767 | <p id="rfc.section.3.3.2.p.1">MIME provides for a number of "multipart" types -- encapsulations of one or more entities within a single message-body. All |
|---|
| 768 | multipart types share a common syntax, as defined in <a href="http://tools.ietf.org/html/rfc2046#section-5.1.1">Section 5.1.1</a> of <a href="#RFC2046" id="rfc.xref.RFC2046.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a>, and <em class="bcp14">MUST</em> include a boundary parameter as part of the media type value. The message body is itself a protocol element and <em class="bcp14">MUST</em> therefore use only CRLF to represent line breaks between body-parts. Unlike in RFC 2046, the epilogue of any multipart message <em class="bcp14">MUST</em> be empty; HTTP applications <em class="bcp14">MUST NOT</em> transmit the epilogue (even if the original multipart contains an epilogue). These restrictions exist in order to preserve |
|---|
| 769 | the self-delimiting nature of a multipart message-body, wherein the "end" of the message-body is indicated by the ending multipart |
|---|
| 770 | boundary. |
|---|
| 771 | </p> |
|---|
| 772 | <p id="rfc.section.3.3.2.p.2">In general, HTTP treats a multipart message-body no differently than any other media type: strictly as payload. The one exception |
|---|
| 773 | is the "multipart/byteranges" type (<a href="p5-range.html#internet.media.type.multipart.byteranges" title="Internet Media Type multipart/byteranges">Appendix A</a> of <a href="#Part5" id="rfc.xref.Part5.2"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>) when it appears in a 206 (Partial Content) response. |
|---|
| 774 | </p> |
|---|
| 775 | <p id="rfc.section.3.3.2.p.3">In general, an HTTP user agent <em class="bcp14">SHOULD</em> follow the same or similar behavior as a MIME user agent would upon receipt of a multipart type. If an application receives |
|---|
| 776 | an unrecognized multipart subtype, the application <em class="bcp14">MUST</em> treat it as being equivalent to "multipart/mixed". |
|---|
| 777 | </p> |
|---|
| 778 | <dl class="empty"> |
|---|
| 779 | <dd> <b>Note:</b> The "multipart/form-data" type has been specifically defined for carrying form data suitable for processing via the POST request |
|---|
| 780 | method, as described in <a href="#RFC2388" id="rfc.xref.RFC2388.1"><cite title="Returning Values from Forms: multipart/form-data">[RFC2388]</cite></a>. |
|---|
| 781 | </dd> |
|---|
| 782 | </dl> |
|---|
| 783 | <h2 id="rfc.section.3.4"><a href="#rfc.section.3.4">3.4</a> <a id="quality.values" href="#quality.values">Quality Values</a></h2> |
|---|
| 784 | <p id="rfc.section.3.4.p.1">HTTP content negotiation (<a href="#content.negotiation" title="Content Negotiation">Section 5</a>) uses short "floating point" numbers to indicate the relative importance ("weight") of various negotiable parameters. A weight |
|---|
| 785 | is normalized to a real number in the range 0 through 1, where 0 is the minimum and 1 the maximum value. If a parameter has |
|---|
| 786 | a quality value of 0, then content with this parameter is `not acceptable' for the client. HTTP/1.1 applications <em class="bcp14">MUST NOT</em> generate more than three digits after the decimal point. User configuration of these values <em class="bcp14">SHOULD</em> also be limited in this fashion. |
|---|
| 787 | </p> |
|---|
| 788 | <div id="rfc.figure.u.11"></div><pre class="inline"><span id="rfc.iref.g.10"></span> <a href="#quality.values" class="smpl">qvalue</a> = ( "0" [ "." 0*3<a href="#notation" class="smpl">DIGIT</a> ] ) |
|---|
| 789 | | ( "1" [ "." 0*3("0") ] ) |
|---|
| 790 | </pre><p id="rfc.section.3.4.p.3">"Quality values" is a misnomer, since these values merely represent relative degradation in desired quality.</p> |
|---|
| 791 | <h2 id="rfc.section.3.5"><a href="#rfc.section.3.5">3.5</a> <a id="language.tags" href="#language.tags">Language Tags</a></h2> |
|---|
| 792 | <p id="rfc.section.3.5.p.1">A language tag identifies a natural language spoken, written, or otherwise conveyed by human beings for communication of information |
|---|
| 793 | to other human beings. Computer languages are explicitly excluded. HTTP uses language tags within the Accept-Language and |
|---|
| 794 | Content-Language fields. |
|---|
| 795 | </p> |
|---|
| 796 | <p id="rfc.section.3.5.p.2">The syntax and registry of HTTP language tags is the same as that defined by <a href="#RFC1766" id="rfc.xref.RFC1766.1"><cite title="Tags for the Identification of Languages">[RFC1766]</cite></a>. In summary, a language tag is composed of 1 or more parts: A primary language tag and a possibly empty series of subtags: |
|---|
| 797 | </p> |
|---|
| 798 | <div id="rfc.figure.u.12"></div><pre class="inline"><span id="rfc.iref.g.11"></span><span id="rfc.iref.g.12"></span><span id="rfc.iref.g.13"></span> <a href="#language.tags" class="smpl">language-tag</a> = <a href="#language.tags" class="smpl">primary-tag</a> *( "-" <a href="#language.tags" class="smpl">subtag</a> ) |
|---|
| 799 | <a href="#language.tags" class="smpl">primary-tag</a> = 1*8<a href="#notation" class="smpl">ALPHA</a> |
|---|
| 800 | <a href="#language.tags" class="smpl">subtag</a> = 1*8<a href="#notation" class="smpl">ALPHA</a> |
|---|
| 801 | </pre><p id="rfc.section.3.5.p.4">White space is not allowed within the tag and all tags are case-insensitive. The name space of language tags is administered |
|---|
| 802 | by the IANA. Example tags include: |
|---|
| 803 | </p> |
|---|
| 804 | <div id="rfc.figure.u.13"></div><pre class="text"> en, en-US, en-cockney, i-cherokee, x-pig-latin |
|---|
| 805 | </pre><p id="rfc.section.3.5.p.6">where any two-letter primary-tag is an ISO-639 language abbreviation and any two-letter initial subtag is an ISO-3166 country |
|---|
| 806 | code. (The last three tags above are not registered tags; all but the last are examples of tags which could be registered |
|---|
| 807 | in future.) |
|---|
| 808 | </p> |
|---|
| 809 | <h1 id="rfc.section.4"><a href="#rfc.section.4">4.</a> <a id="entity" href="#entity">Entity</a></h1> |
|---|
| 810 | <p id="rfc.section.4.p.1">Request and Response messages <em class="bcp14">MAY</em> transfer an entity if not otherwise restricted by the request method or response status code. An entity consists of entity-header |
|---|
| 811 | fields and an entity-body, although some responses will only include the entity-headers. |
|---|
| 812 | </p> |
|---|
| 813 | <p id="rfc.section.4.p.2">In this section, both sender and recipient refer to either the client or the server, depending on who sends and who receives |
|---|
| 814 | the entity. |
|---|
| 815 | </p> |
|---|
| 816 | <h2 id="rfc.section.4.1"><a href="#rfc.section.4.1">4.1</a> <a id="entity.header.fields" href="#entity.header.fields">Entity Header Fields</a></h2> |
|---|
| 817 | <p id="rfc.section.4.1.p.1">Entity-header fields define metainformation about the entity-body or, if no body is present, about the resource identified |
|---|
| 818 | by the request. |
|---|
| 819 | </p> |
|---|
| 820 | <div id="rfc.figure.u.14"></div><pre class="inline"><span id="rfc.iref.g.14"></span><span id="rfc.iref.g.15"></span> <a href="#entity.header.fields" class="smpl">entity-header</a> = <a href="#header.content-encoding" class="smpl">Content-Encoding</a> ; <a href="#header.content-encoding" id="rfc.xref.header.content-encoding.2" title="Content-Encoding">Section 6.5</a> |
|---|
| 821 | | <a href="#header.content-language" class="smpl">Content-Language</a> ; <a href="#header.content-language" id="rfc.xref.header.content-language.1" title="Content-Language">Section 6.6</a> |
|---|
| 822 | | <a href="#abnf.dependencies" class="smpl">Content-Length</a> ; <a href="#Part1" id="rfc.xref.Part1.12"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="p1-messaging.html#header.content-length" title="Content-Length">Section 8.2</a> |
|---|
| 823 | | <a href="#header.content-location" class="smpl">Content-Location</a> ; <a href="#header.content-location" id="rfc.xref.header.content-location.1" title="Content-Location">Section 6.7</a> |
|---|
| 824 | | <a href="#header.content-md5" class="smpl">Content-MD5</a> ; <a href="#header.content-md5" id="rfc.xref.header.content-md5.1" title="Content-MD5">Section 6.8</a> |
|---|
| 825 | | <a href="#abnf.dependencies" class="smpl">Content-Range</a> ; <a href="#Part5" id="rfc.xref.Part5.3"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a>, <a href="p5-range.html#header.content-range" title="Content-Range">Section 6.2</a> |
|---|
| 826 | | <a href="#header.content-type" class="smpl">Content-Type</a> ; <a href="#header.content-type" id="rfc.xref.header.content-type.2" title="Content-Type">Section 6.9</a> |
|---|
| 827 | | <a href="#abnf.dependencies" class="smpl">Expires</a> ; <a href="#Part6" id="rfc.xref.Part6.2"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>, <a href="p6-cache.html#header.expires" title="Expires">Section 16.3</a> |
|---|
| 828 | | <a href="#abnf.dependencies" class="smpl">Last-Modified</a> ; <a href="#Part4" id="rfc.xref.Part4.2"><cite title="HTTP/1.1, part 4: Conditional Requests">[Part4]</cite></a>, <a href="p4-conditional.html#header.last-modified" title="Last-Modified">Section 7.6</a> |
|---|
| 829 | | <a href="#entity.header.fields" class="smpl">extension-header</a> |
|---|
| 830 | |
|---|
| 831 | <a href="#entity.header.fields" class="smpl">extension-header</a> = <a href="#abnf.dependencies" class="smpl">message-header</a> |
|---|
| 832 | </pre><p id="rfc.section.4.1.p.3">The extension-header mechanism allows additional entity-header fields to be defined without changing the protocol, but these |
|---|
| 833 | fields cannot be assumed to be recognizable by the recipient. Unrecognized header fields <em class="bcp14">SHOULD</em> be ignored by the recipient and <em class="bcp14">MUST</em> be forwarded by transparent proxies. |
|---|
| 834 | </p> |
|---|
| 835 | <h2 id="rfc.section.4.2"><a href="#rfc.section.4.2">4.2</a> <a id="entity.body" href="#entity.body">Entity Body</a></h2> |
|---|
| 836 | <p id="rfc.section.4.2.p.1">The entity-body (if any) sent with an HTTP request or response is in a format and encoding defined by the entity-header fields.</p> |
|---|
| 837 | <div id="rfc.figure.u.15"></div><pre class="inline"><span id="rfc.iref.g.16"></span> <a href="#entity.body" class="smpl">entity-body</a> = *<a href="#notation" class="smpl">OCTET</a> |
|---|
| 838 | </pre><p id="rfc.section.4.2.p.3">An entity-body is only present in a message when a message-body is present, as described in <a href="p1-messaging.html#message.body" title="Message Body">Section 4.3</a> of <a href="#Part1" id="rfc.xref.Part1.13"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>. The entity-body is obtained from the message-body by decoding any Transfer-Encoding that might have been applied to ensure |
|---|
| 839 | safe and proper transfer of the message. |
|---|
| 840 | </p> |
|---|
| 841 | <h3 id="rfc.section.4.2.1"><a href="#rfc.section.4.2.1">4.2.1</a> <a id="type" href="#type">Type</a></h3> |
|---|
| 842 | <p id="rfc.section.4.2.1.p.1">When an entity-body is included with a message, the data type of that body is determined via the header fields Content-Type |
|---|
| 843 | and Content-Encoding. These define a two-layer, ordered encoding model: |
|---|
| 844 | </p> |
|---|
| 845 | <div id="rfc.figure.u.16"></div><pre class="text"> entity-body := Content-Encoding( Content-Type( data ) ) |
|---|
| 846 | </pre><p id="rfc.section.4.2.1.p.3">Content-Type specifies the media type of the underlying data. Content-Encoding may be used to indicate any additional content |
|---|
| 847 | codings applied to the data, usually for the purpose of data compression, that are a property of the requested resource. There |
|---|
| 848 | is no default encoding. |
|---|
| 849 | </p> |
|---|
| 850 | <p id="rfc.section.4.2.1.p.4">Any HTTP/1.1 message containing an entity-body <em class="bcp14">SHOULD</em> include a Content-Type header field defining the media type of that body. If and only if the media type is not given by a |
|---|
| 851 | Content-Type field, the recipient <em class="bcp14">MAY</em> attempt to guess the media type via inspection of its content and/or the name extension(s) of the URI used to identify the |
|---|
| 852 | resource. If the media type remains unknown, the recipient <em class="bcp14">SHOULD</em> treat it as type "application/octet-stream". |
|---|
| 853 | </p> |
|---|
| 854 | <h3 id="rfc.section.4.2.2"><a href="#rfc.section.4.2.2">4.2.2</a> <a id="entity.length" href="#entity.length">Entity Length</a></h3> |
|---|
| 855 | <p id="rfc.section.4.2.2.p.1">The entity-length of a message is the length of the message-body before any transfer-codings have been applied. <a href="p1-messaging.html#message.length" title="Message Length">Section 4.4</a> of <a href="#Part1" id="rfc.xref.Part1.14"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a> defines how the transfer-length of a message-body is determined. |
|---|
| 856 | </p> |
|---|
| 857 | <h1 id="rfc.section.5"><a href="#rfc.section.5">5.</a> <a id="content.negotiation" href="#content.negotiation">Content Negotiation</a></h1> |
|---|
| 858 | <p id="rfc.section.5.p.1">Most HTTP responses include an entity which contains information for interpretation by a human user. Naturally, it is desirable |
|---|
| 859 | to supply the user with the "best available" entity corresponding to the request. Unfortunately for servers and caches, not |
|---|
| 860 | all users have the same preferences for what is "best," and not all user agents are equally capable of rendering all entity |
|---|
| 861 | types. For that reason, HTTP has provisions for several mechanisms for "content negotiation" -- the process of selecting the |
|---|
| 862 | best representation for a given response when there are multiple representations available. |
|---|
| 863 | </p> |
|---|
| 864 | <dl class="empty"> |
|---|
| 865 | <dd> <b>Note:</b> This is not called "format negotiation" because the alternate representations may be of the same media type, but use different |
|---|
| 866 | capabilities of that type, be in different languages, etc. |
|---|
| 867 | </dd> |
|---|
| 868 | </dl> |
|---|
| 869 | <p id="rfc.section.5.p.2">Any response containing an entity-body <em class="bcp14">MAY</em> be subject to negotiation, including error responses. |
|---|
| 870 | </p> |
|---|
| 871 | <p id="rfc.section.5.p.3">There are two kinds of content negotiation which are possible in HTTP: server-driven and agent-driven negotiation. These two |
|---|
| 872 | kinds of negotiation are orthogonal and thus may be used separately or in combination. One method of combination, referred |
|---|
| 873 | to as transparent negotiation, occurs when a cache uses the agent-driven negotiation information provided by the origin server |
|---|
| 874 | in order to provide server-driven negotiation for subsequent requests. |
|---|
| 875 | </p> |
|---|
| 876 | <h2 id="rfc.section.5.1"><a href="#rfc.section.5.1">5.1</a> <a id="server-driven.negotiation" href="#server-driven.negotiation">Server-driven Negotiation</a></h2> |
|---|
| 877 | <p id="rfc.section.5.1.p.1">If the selection of the best representation for a response is made by an algorithm located at the server, it is called server-driven |
|---|
| 878 | negotiation. Selection is based on the available representations of the response (the dimensions over which it can vary; e.g. |
|---|
| 879 | language, content-coding, etc.) and the contents of particular header fields in the request message or on other information |
|---|
| 880 | pertaining to the request (such as the network address of the client). |
|---|
| 881 | </p> |
|---|
| 882 | <p id="rfc.section.5.1.p.2">Server-driven negotiation is advantageous when the algorithm for selecting from among the available representations is difficult |
|---|
| 883 | to describe to the user agent, or when the server desires to send its "best guess" to the client along with the first response |
|---|
| 884 | (hoping to avoid the round-trip delay of a subsequent request if the "best guess" is good enough for the user). In order to |
|---|
| 885 | improve the server's guess, the user agent <em class="bcp14">MAY</em> include request header fields (Accept, Accept-Language, Accept-Encoding, etc.) which describe its preferences for such a response. |
|---|
| 886 | </p> |
|---|
| 887 | <p id="rfc.section.5.1.p.3">Server-driven negotiation has disadvantages: </p> |
|---|
| 888 | <ol> |
|---|
| 889 | <li>It is impossible for the server to accurately determine what might be "best" for any given user, since that would require |
|---|
| 890 | complete knowledge of both the capabilities of the user agent and the intended use for the response (e.g., does the user want |
|---|
| 891 | to view it on screen or print it on paper?). |
|---|
| 892 | </li> |
|---|
| 893 | <li>Having the user agent describe its capabilities in every request can be both very inefficient (given that only a small percentage |
|---|
| 894 | of responses have multiple representations) and a potential violation of the user's privacy. |
|---|
| 895 | </li> |
|---|
| 896 | <li>It complicates the implementation of an origin server and the algorithms for generating responses to a request.</li> |
|---|
| 897 | <li>It may limit a public cache's ability to use the same response for multiple user's requests.</li> |
|---|
| 898 | </ol> |
|---|
| 899 | <p id="rfc.section.5.1.p.4">HTTP/1.1 includes the following request-header fields for enabling server-driven negotiation through description of user agent |
|---|
| 900 | capabilities and user preferences: Accept (<a href="#header.accept" id="rfc.xref.header.accept.2" title="Accept">Section 6.1</a>), Accept-Charset (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.1" title="Accept-Charset">Section 6.2</a>), Accept-Encoding (<a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.2" title="Accept-Encoding">Section 6.3</a>), Accept-Language (<a href="#header.accept-language" id="rfc.xref.header.accept-language.1" title="Accept-Language">Section 6.4</a>), and User-Agent (<a href="p2-semantics.html#header.user-agent" title="User-Agent">Section 10.9</a> of <a href="#Part2" id="rfc.xref.Part2.1"><cite title="HTTP/1.1, part 2: Message Semantics">[Part2]</cite></a>). However, an origin server is not limited to these dimensions and <em class="bcp14">MAY</em> vary the response based on any aspect of the request, including information outside the request-header fields or within extension |
|---|
| 901 | header fields not defined by this specification. |
|---|
| 902 | </p> |
|---|
| 903 | <p id="rfc.section.5.1.p.5">The Vary header field (<a href="p6-cache.html#header.vary" title="Vary">Section 16.5</a> of <a href="#Part6" id="rfc.xref.Part6.3"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>) can be used to express the parameters the server uses to select a representation that is subject to server-driven negotiation. |
|---|
| 904 | </p> |
|---|
| 905 | <h2 id="rfc.section.5.2"><a href="#rfc.section.5.2">5.2</a> <a id="agent-driven.negotiation" href="#agent-driven.negotiation">Agent-driven Negotiation</a></h2> |
|---|
| 906 | <p id="rfc.section.5.2.p.1">With agent-driven negotiation, selection of the best representation for a response is performed by the user agent after receiving |
|---|
| 907 | an initial response from the origin server. Selection is based on a list of the available representations of the response |
|---|
| 908 | included within the header fields or entity-body of the initial response, with each representation identified by its own URI. |
|---|
| 909 | Selection from among the representations may be performed automatically (if the user agent is capable of doing so) or manually |
|---|
| 910 | by the user selecting from a generated (possibly hypertext) menu. |
|---|
| 911 | </p> |
|---|
| 912 | <p id="rfc.section.5.2.p.2">Agent-driven negotiation is advantageous when the response would vary over commonly-used dimensions (such as type, language, |
|---|
| 913 | or encoding), when the origin server is unable to determine a user agent's capabilities from examining the request, and generally |
|---|
| 914 | when public caches are used to distribute server load and reduce network usage. |
|---|
| 915 | </p> |
|---|
| 916 | <p id="rfc.section.5.2.p.3">Agent-driven negotiation suffers from the disadvantage of needing a second request to obtain the best alternate representation. |
|---|
| 917 | This second request is only efficient when caching is used. In addition, this specification does not define any mechanism |
|---|
| 918 | for supporting automatic selection, though it also does not prevent any such mechanism from being developed as an extension |
|---|
| 919 | and used within HTTP/1.1. |
|---|
| 920 | </p> |
|---|
| 921 | <p id="rfc.section.5.2.p.4">HTTP/1.1 defines the 300 (Multiple Choices) and 406 (Not Acceptable) status codes for enabling agent-driven negotiation when |
|---|
| 922 | the server is unwilling or unable to provide a varying response using server-driven negotiation. |
|---|
| 923 | </p> |
|---|
| 924 | <h2 id="rfc.section.5.3"><a href="#rfc.section.5.3">5.3</a> <a id="transparent.negotiation" href="#transparent.negotiation">Transparent Negotiation</a></h2> |
|---|
| 925 | <p id="rfc.section.5.3.p.1">Transparent negotiation is a combination of both server-driven and agent-driven negotiation. When a cache is supplied with |
|---|
| 926 | a form of the list of available representations of the response (as in agent-driven negotiation) and the dimensions of variance |
|---|
| 927 | are completely understood by the cache, then the cache becomes capable of performing server-driven negotiation on behalf of |
|---|
| 928 | the origin server for subsequent requests on that resource. |
|---|
| 929 | </p> |
|---|
| 930 | <p id="rfc.section.5.3.p.2">Transparent negotiation has the advantage of distributing the negotiation work that would otherwise be required of the origin |
|---|
| 931 | server and also removing the second request delay of agent-driven negotiation when the cache is able to correctly guess the |
|---|
| 932 | right response. |
|---|
| 933 | </p> |
|---|
| 934 | <p id="rfc.section.5.3.p.3">This specification does not define any mechanism for transparent negotiation, though it also does not prevent any such mechanism |
|---|
| 935 | from being developed as an extension that could be used within HTTP/1.1. |
|---|
| 936 | </p> |
|---|
| 937 | <h1 id="rfc.section.6"><a href="#rfc.section.6">6.</a> <a id="header.fields" href="#header.fields">Header Field Definitions</a></h1> |
|---|
| 938 | <p id="rfc.section.6.p.1">This section defines the syntax and semantics of HTTP/1.1 header fields related to the payload of messages.</p> |
|---|
| 939 | <p id="rfc.section.6.p.2">For entity-header fields, both sender and recipient refer to either the client or the server, depending on who sends and who |
|---|
| 940 | receives the entity. |
|---|
| 941 | </p> |
|---|
| 942 | <div id="rfc.iref.a.1"></div> |
|---|
| 943 | <div id="rfc.iref.h.1"></div> |
|---|
| 944 | <h2 id="rfc.section.6.1"><a href="#rfc.section.6.1">6.1</a> <a id="header.accept" href="#header.accept">Accept</a></h2> |
|---|
| 945 | <p id="rfc.section.6.1.p.1">The Accept request-header field can be used to specify certain media types which are acceptable for the response. Accept headers |
|---|
| 946 | can be used to indicate that the request is specifically limited to a small set of desired types, as in the case of a request |
|---|
| 947 | for an in-line image. |
|---|
| 948 | </p> |
|---|
| 949 | <div id="rfc.figure.u.17"></div><pre class="inline"><span id="rfc.iref.g.17"></span><span id="rfc.iref.g.18"></span><span id="rfc.iref.g.19"></span><span id="rfc.iref.g.20"></span> <a href="#header.accept" class="smpl">Accept</a> = "Accept" ":" |
|---|
| 950 | #( <a href="#header.accept" class="smpl">media-range</a> [ <a href="#header.accept" class="smpl">accept-params</a> ] ) |
|---|
| 951 | |
|---|
| 952 | <a href="#header.accept" class="smpl">media-range</a> = ( "*/*" |
|---|
| 953 | | ( <a href="#media.types" class="smpl">type</a> "/" "*" ) |
|---|
| 954 | | ( <a href="#media.types" class="smpl">type</a> "/" <a href="#media.types" class="smpl">subtype</a> ) |
|---|
| 955 | ) *( ";" <a href="#rule.parameter" class="smpl">parameter</a> ) |
|---|
| 956 | <a href="#header.accept" class="smpl">accept-params</a> = ";" "q" "=" <a href="#quality.values" class="smpl">qvalue</a> *( <a href="#header.accept" class="smpl">accept-extension</a> ) |
|---|
| 957 | <a href="#header.accept" class="smpl">accept-extension</a> = ";" <a href="#notation" class="smpl">token</a> [ "=" ( <a href="#notation" class="smpl">token</a> | <a href="#notation" class="smpl">quoted-string</a> ) ] |
|---|
| 958 | </pre><p id="rfc.section.6.1.p.3">The asterisk "*" character is used to group media types into ranges, with "*/*" indicating all media types and "type/*" indicating |
|---|
| 959 | all subtypes of that type. The media-range <em class="bcp14">MAY</em> include media type parameters that are applicable to that range. |
|---|
| 960 | </p> |
|---|
| 961 | <p id="rfc.section.6.1.p.4">Each media-range <em class="bcp14">MAY</em> be followed by one or more accept-params, beginning with the "q" parameter for indicating a relative quality factor. The first |
|---|
| 962 | "q" parameter (if any) separates the media-range parameter(s) from the accept-params. Quality factors allow the user or user |
|---|
| 963 | agent to indicate the relative degree of preference for that media-range, using the qvalue scale from 0 to 1 (<a href="#quality.values" title="Quality Values">Section 3.4</a>). The default value is q=1. |
|---|
| 964 | </p> |
|---|
| 965 | <dl class="empty"> |
|---|
| 966 | <dd> <b>Note:</b> Use of the "q" parameter name to separate media type parameters from Accept extension parameters is due to historical practice. |
|---|
| 967 | Although this prevents any media type parameter named "q" from being used with a media range, such an event is believed to |
|---|
| 968 | be unlikely given the lack of any "q" parameters in the IANA media type registry and the rare usage of any media type parameters |
|---|
| 969 | in Accept. Future media types are discouraged from registering any parameter named "q". |
|---|
| 970 | </dd> |
|---|
| 971 | </dl> |
|---|
| 972 | <p id="rfc.section.6.1.p.5">The example</p> |
|---|
| 973 | <div id="rfc.figure.u.18"></div><pre class="text"> Accept: audio/*; q=0.2, audio/basic |
|---|
| 974 | </pre><p id="rfc.section.6.1.p.7"> <em class="bcp14">SHOULD</em> be interpreted as "I prefer audio/basic, but send me any audio type if it is the best available after an 80% mark-down in |
|---|
| 975 | quality." |
|---|
| 976 | </p> |
|---|
| 977 | <p id="rfc.section.6.1.p.8">If no Accept header field is present, then it is assumed that the client accepts all media types. If an Accept header field |
|---|
| 978 | is present, and if the server cannot send a response which is acceptable according to the combined Accept field value, then |
|---|
| 979 | the server <em class="bcp14">SHOULD</em> send a 406 (Not Acceptable) response. |
|---|
| 980 | </p> |
|---|
| 981 | <p id="rfc.section.6.1.p.9">A more elaborate example is</p> |
|---|
| 982 | <div id="rfc.figure.u.19"></div><pre class="text"> Accept: text/plain; q=0.5, text/html, |
|---|
| 983 | text/x-dvi; q=0.8, text/x-c |
|---|
| 984 | </pre><p id="rfc.section.6.1.p.11">Verbally, this would be interpreted as "text/html and text/x-c are the preferred media types, but if they do not exist, then |
|---|
| 985 | send the text/x-dvi entity, and if that does not exist, send the text/plain entity." |
|---|
| 986 | </p> |
|---|
| 987 | <p id="rfc.section.6.1.p.12">Media ranges can be overridden by more specific media ranges or specific media types. If more than one media range applies |
|---|
| 988 | to a given type, the most specific reference has precedence. For example, |
|---|
| 989 | </p> |
|---|
| 990 | <div id="rfc.figure.u.20"></div><pre class="text"> Accept: text/*, text/html, text/html;level=1, */* |
|---|
| 991 | </pre><p id="rfc.section.6.1.p.14">have the following precedence:</p> |
|---|
| 992 | <div id="rfc.figure.u.21"></div><pre class="text"> 1) text/html;level=1 |
|---|
| 993 | 2) text/html |
|---|
| 994 | 3) text/* |
|---|
| 995 | 4) */* |
|---|
| 996 | </pre><p id="rfc.section.6.1.p.16">The media type quality factor associated with a given type is determined by finding the media range with the highest precedence |
|---|
| 997 | which matches that type. For example, |
|---|
| 998 | </p> |
|---|
| 999 | <div id="rfc.figure.u.22"></div><pre class="text"> Accept: text/*;q=0.3, text/html;q=0.7, text/html;level=1, |
|---|
| 1000 | text/html;level=2;q=0.4, */*;q=0.5 |
|---|
| 1001 | </pre><p id="rfc.section.6.1.p.18">would cause the following values to be associated:</p> |
|---|
| 1002 | <div id="rfc.figure.u.23"></div><pre class="text"> text/html;level=1 = 1 |
|---|
| 1003 | text/html = 0.7 |
|---|
| 1004 | text/plain = 0.3 |
|---|
| 1005 | image/jpeg = 0.5 |
|---|
| 1006 | text/html;level=2 = 0.4 |
|---|
| 1007 | text/html;level=3 = 0.7 |
|---|
| 1008 | </pre><p id="rfc.section.6.1.p.20"> <b>Note:</b> A user agent might be provided with a default set of quality values for certain media ranges. However, unless the user agent |
|---|
| 1009 | is a closed system which cannot interact with other rendering agents, this default set ought to be configurable by the user. |
|---|
| 1010 | </p> |
|---|
| 1011 | <div id="rfc.iref.a.2"></div> |
|---|
| 1012 | <div id="rfc.iref.h.2"></div> |
|---|
| 1013 | <h2 id="rfc.section.6.2"><a href="#rfc.section.6.2">6.2</a> <a id="header.accept-charset" href="#header.accept-charset">Accept-Charset</a></h2> |
|---|
| 1014 | <p id="rfc.section.6.2.p.1">The Accept-Charset request-header field can be used to indicate what character sets are acceptable for the response. This |
|---|
| 1015 | field allows clients capable of understanding more comprehensive or special-purpose character sets to signal that capability |
|---|
| 1016 | to a server which is capable of representing documents in those character sets. |
|---|
| 1017 | </p> |
|---|
| 1018 | <div id="rfc.figure.u.24"></div><pre class="inline"><span id="rfc.iref.g.21"></span> <a href="#header.accept-charset" class="smpl">Accept-Charset</a> = "Accept-Charset" ":" |
|---|
| 1019 | 1#( ( <a href="#rule.charset" class="smpl">charset</a> | "*" ) [ ";" "q" "=" <a href="#quality.values" class="smpl">qvalue</a> ] ) |
|---|
| 1020 | </pre><p id="rfc.section.6.2.p.3">Character set values are described in <a href="#character.sets" title="Character Sets">Section 3.1</a>. Each charset <em class="bcp14">MAY</em> be given an associated quality value which represents the user's preference for that charset. The default value is q=1. An |
|---|
| 1021 | example is |
|---|
| 1022 | </p> |
|---|
| 1023 | <div id="rfc.figure.u.25"></div><pre class="text"> Accept-Charset: iso-8859-5, unicode-1-1;q=0.8 |
|---|
| 1024 | </pre><p id="rfc.section.6.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character set (including ISO-8859-1) which is |
|---|
| 1025 | not mentioned elsewhere in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then all character sets |
|---|
| 1026 | not explicitly mentioned get a quality value of 0, except for ISO-8859-1, which gets a quality value of 1 if not explicitly |
|---|
| 1027 | mentioned. |
|---|
| 1028 | </p> |
|---|
| 1029 | <p id="rfc.section.6.2.p.6">If no Accept-Charset header is present, the default is that any character set is acceptable. If an Accept-Charset header is |
|---|
| 1030 | present, and if the server cannot send a response which is acceptable according to the Accept-Charset header, then the server <em class="bcp14">SHOULD</em> send an error response with the 406 (Not Acceptable) status code, though the sending of an unacceptable response is also allowed. |
|---|
| 1031 | </p> |
|---|
| 1032 | <div id="rfc.iref.a.3"></div> |
|---|
| 1033 | <div id="rfc.iref.h.3"></div> |
|---|
| 1034 | <h2 id="rfc.section.6.3"><a href="#rfc.section.6.3">6.3</a> <a id="header.accept-encoding" href="#header.accept-encoding">Accept-Encoding</a></h2> |
|---|
| 1035 | <p id="rfc.section.6.3.p.1">The Accept-Encoding request-header field is similar to Accept, but restricts the content-codings (<a href="#content.codings" title="Content Codings">Section 3.2</a>) that are acceptable in the response. |
|---|
| 1036 | </p> |
|---|
| 1037 | <div id="rfc.figure.u.26"></div><pre class="inline"><span id="rfc.iref.g.22"></span><span id="rfc.iref.g.23"></span> <a href="#header.accept-encoding" class="smpl">Accept-Encoding</a> = "Accept-Encoding" ":" |
|---|
| 1038 | #( <a href="#header.accept-encoding" class="smpl">codings</a> [ ";" "q" "=" <a href="#quality.values" class="smpl">qvalue</a> ] ) |
|---|
| 1039 | <a href="#header.accept-encoding" class="smpl">codings</a> = ( <a href="#content.codings" class="smpl">content-coding</a> | "*" ) |
|---|
| 1040 | </pre><p id="rfc.section.6.3.p.3">Each codings value <em class="bcp14">MAY</em> be given an associated quality value which represents the preference for that encoding. The default value is q=1. |
|---|
| 1041 | </p> |
|---|
| 1042 | <p id="rfc.section.6.3.p.4">Examples of its use are:</p> |
|---|
| 1043 | <div id="rfc.figure.u.27"></div><pre class="text"> Accept-Encoding: compress, gzip |
|---|
| 1044 | Accept-Encoding: |
|---|
| 1045 | Accept-Encoding: * |
|---|
| 1046 | Accept-Encoding: compress;q=0.5, gzip;q=1.0 |
|---|
| 1047 | Accept-Encoding: gzip;q=1.0, identity; q=0.5, *;q=0 |
|---|
| 1048 | </pre><p id="rfc.section.6.3.p.6">A server tests whether a content-coding is acceptable, according to an Accept-Encoding field, using these rules: </p> |
|---|
| 1049 | <ol> |
|---|
| 1050 | <li>If the content-coding is one of the content-codings listed in the Accept-Encoding field, then it is acceptable, unless it |
|---|
| 1051 | is accompanied by a qvalue of 0. (As defined in <a href="#quality.values" title="Quality Values">Section 3.4</a>, a qvalue of 0 means "not acceptable.") |
|---|
| 1052 | </li> |
|---|
| 1053 | <li>The special "*" symbol in an Accept-Encoding field matches any available content-coding not explicitly listed in the header |
|---|
| 1054 | field. |
|---|
| 1055 | </li> |
|---|
| 1056 | <li>If multiple content-codings are acceptable, then the acceptable content-coding with the highest non-zero qvalue is preferred.</li> |
|---|
| 1057 | <li>The "identity" content-coding is always acceptable, unless specifically refused because the Accept-Encoding field includes |
|---|
| 1058 | "identity;q=0", or because the field includes "*;q=0" and does not explicitly include the "identity" content-coding. If the |
|---|
| 1059 | Accept-Encoding field-value is empty, then only the "identity" encoding is acceptable. |
|---|
| 1060 | </li> |
|---|
| 1061 | </ol> |
|---|
| 1062 | <p id="rfc.section.6.3.p.7">If an Accept-Encoding field is present in a request, and if the server cannot send a response which is acceptable according |
|---|
| 1063 | to the Accept-Encoding header, then the server <em class="bcp14">SHOULD</em> send an error response with the 406 (Not Acceptable) status code. |
|---|
| 1064 | </p> |
|---|
| 1065 | <p id="rfc.section.6.3.p.8">If no Accept-Encoding field is present in a request, the server <em class="bcp14">MAY</em> assume that the client will accept any content coding. In this case, if "identity" is one of the available content-codings, |
|---|
| 1066 | then the server <em class="bcp14">SHOULD</em> use the "identity" content-coding, unless it has additional information that a different content-coding is meaningful to the |
|---|
| 1067 | client. |
|---|
| 1068 | </p> |
|---|
| 1069 | <dl class="empty"> |
|---|
| 1070 | <dd> <b>Note:</b> If the request does not include an Accept-Encoding field, and if the "identity" content-coding is unavailable, then content-codings |
|---|
| 1071 | commonly understood by HTTP/1.0 clients (i.e., "gzip" and "compress") are preferred; some older clients improperly display |
|---|
| 1072 | messages sent with other content-codings. The server might also make this decision based on information about the particular |
|---|
| 1073 | user-agent or client. |
|---|
| 1074 | </dd> |
|---|
| 1075 | <dd> <b>Note:</b> Most HTTP/1.0 applications do not recognize or obey qvalues associated with content-codings. This means that qvalues will |
|---|
| 1076 | not work and are not permitted with x-gzip or x-compress. |
|---|
| 1077 | </dd> |
|---|
| 1078 | </dl> |
|---|
| 1079 | <div id="rfc.iref.a.4"></div> |
|---|
| 1080 | <div id="rfc.iref.h.4"></div> |
|---|
| 1081 | <h2 id="rfc.section.6.4"><a href="#rfc.section.6.4">6.4</a> <a id="header.accept-language" href="#header.accept-language">Accept-Language</a></h2> |
|---|
| 1082 | <p id="rfc.section.6.4.p.1">The Accept-Language request-header field is similar to Accept, but restricts the set of natural languages that are preferred |
|---|
| 1083 | as a response to the request. Language tags are defined in <a href="#language.tags" title="Language Tags">Section 3.5</a>. |
|---|
| 1084 | </p> |
|---|
| 1085 | <div id="rfc.figure.u.28"></div><pre class="inline"><span id="rfc.iref.g.24"></span><span id="rfc.iref.g.25"></span> <a href="#header.accept-language" class="smpl">Accept-Language</a> = "Accept-Language" ":" |
|---|
| 1086 | 1#( <a href="#header.accept-language" class="smpl">language-range</a> [ ";" "q" "=" <a href="#quality.values" class="smpl">qvalue</a> ] ) |
|---|
| 1087 | <a href="#header.accept-language" class="smpl">language-range</a> = ( ( 1*8<a href="#notation" class="smpl">ALPHA</a> *( "-" 1*8<a href="#notation" class="smpl">ALPHA</a> ) ) | "*" ) |
|---|
| 1088 | </pre><p id="rfc.section.6.4.p.3">Each language-range <em class="bcp14">MAY</em> be given an associated quality value which represents an estimate of the user's preference for the languages specified by |
|---|
| 1089 | that range. The quality value defaults to "q=1". For example, |
|---|
| 1090 | </p> |
|---|
| 1091 | <div id="rfc.figure.u.29"></div><pre class="text"> Accept-Language: da, en-gb;q=0.8, en;q=0.7 |
|---|
| 1092 | </pre><p id="rfc.section.6.4.p.5">would mean: "I prefer Danish, but will accept British English and other types of English." A language-range matches a language-tag |
|---|
| 1093 | if it exactly equals the tag, or if it exactly equals a prefix of the tag such that the first tag character following the |
|---|
| 1094 | prefix is "-". The special range "*", if present in the Accept-Language field, matches every tag not matched by any other |
|---|
| 1095 | range present in the Accept-Language field. |
|---|
| 1096 | </p> |
|---|
| 1097 | <dl class="empty"> |
|---|
| 1098 | <dd> <b>Note:</b> This use of a prefix matching rule does not imply that language tags are assigned to languages in such a way that it is always |
|---|
| 1099 | true that if a user understands a language with a certain tag, then this user will also understand all languages with tags |
|---|
| 1100 | for which this tag is a prefix. The prefix rule simply allows the use of prefix tags if this is the case. |
|---|
| 1101 | </dd> |
|---|
| 1102 | </dl> |
|---|
| 1103 | <p id="rfc.section.6.4.p.6">The language quality factor assigned to a language-tag by the Accept-Language field is the quality value of the longest language-range |
|---|
| 1104 | in the field that matches the language-tag. If no language-range in the field matches the tag, the language quality factor |
|---|
| 1105 | assigned is 0. If no Accept-Language header is present in the request, the server <em class="bcp14">SHOULD</em> assume that all languages are equally acceptable. If an Accept-Language header is present, then all languages which are assigned |
|---|
| 1106 | a quality factor greater than 0 are acceptable. |
|---|
| 1107 | </p> |
|---|
| 1108 | <p id="rfc.section.6.4.p.7">It might be contrary to the privacy expectations of the user to send an Accept-Language header with the complete linguistic |
|---|
| 1109 | preferences of the user in every request. For a discussion of this issue, see <a href="#privacy.issues.connected.to.accept.headers" title="Privacy Issues Connected to Accept Headers">Section 8.1</a>. |
|---|
| 1110 | </p> |
|---|
| 1111 | <p id="rfc.section.6.4.p.8">As intelligibility is highly dependent on the individual user, it is recommended that client applications make the choice |
|---|
| 1112 | of linguistic preference available to the user. If the choice is not made available, then the Accept-Language header field <em class="bcp14">MUST NOT</em> be given in the request. |
|---|
| 1113 | </p> |
|---|
| 1114 | <dl class="empty"> |
|---|
| 1115 | <dd> <b>Note:</b> When making the choice of linguistic preference available to the user, we remind implementors of the fact that users are not |
|---|
| 1116 | familiar with the details of language matching as described above, and should provide appropriate guidance. As an example, |
|---|
| 1117 | users might assume that on selecting "en-gb", they will be served any kind of English document if British English is not available. |
|---|
| 1118 | A user agent might suggest in such a case to add "en" to get the best matching behavior. |
|---|
| 1119 | </dd> |
|---|
| 1120 | </dl> |
|---|
| 1121 | <div id="rfc.iref.c.2"></div> |
|---|
| 1122 | <div id="rfc.iref.h.5"></div> |
|---|
| 1123 | <h2 id="rfc.section.6.5"><a href="#rfc.section.6.5">6.5</a> <a id="header.content-encoding" href="#header.content-encoding">Content-Encoding</a></h2> |
|---|
| 1124 | <p id="rfc.section.6.5.p.1">The Content-Encoding entity-header field is used as a modifier to the media-type. When present, its value indicates what additional |
|---|
| 1125 | content codings have been applied to the entity-body, and thus what decoding mechanisms must be applied in order to obtain |
|---|
| 1126 | the media-type referenced by the Content-Type header field. Content-Encoding is primarily used to allow a document to be compressed |
|---|
| 1127 | without losing the identity of its underlying media type. |
|---|
| 1128 | </p> |
|---|
| 1129 | <div id="rfc.figure.u.30"></div><pre class="inline"><span id="rfc.iref.g.26"></span> <a href="#header.content-encoding" class="smpl">Content-Encoding</a> = "Content-Encoding" ":" 1#<a href="#content.codings" class="smpl">content-coding</a> |
|---|
| 1130 | </pre><p id="rfc.section.6.5.p.3">Content codings are defined in <a href="#content.codings" title="Content Codings">Section 3.2</a>. An example of its use is |
|---|
| 1131 | </p> |
|---|
| 1132 | <div id="rfc.figure.u.31"></div><pre class="text"> Content-Encoding: gzip |
|---|
| 1133 | </pre><p id="rfc.section.6.5.p.5">The content-coding is a characteristic of the entity identified by the Request-URI. Typically, the entity-body is stored with |
|---|
| 1134 | this encoding and is only decoded before rendering or analogous usage. However, a non-transparent proxy <em class="bcp14">MAY</em> modify the content-coding if the new coding is known to be acceptable to the recipient, unless the "no-transform" cache-control |
|---|
| 1135 | directive is present in the message. |
|---|
| 1136 | </p> |
|---|
| 1137 | <p id="rfc.section.6.5.p.6">If the content-coding of an entity is not "identity", then the response <em class="bcp14">MUST</em> include a Content-Encoding entity-header (<a href="#header.content-encoding" id="rfc.xref.header.content-encoding.3" title="Content-Encoding">Section 6.5</a>) that lists the non-identity content-coding(s) used. |
|---|
| 1138 | </p> |
|---|
| 1139 | <p id="rfc.section.6.5.p.7">If the content-coding of an entity in a request message is not acceptable to the origin server, the server <em class="bcp14">SHOULD</em> respond with a status code of 415 (Unsupported Media Type). |
|---|
| 1140 | </p> |
|---|
| 1141 | <p id="rfc.section.6.5.p.8">If multiple encodings have been applied to an entity, the content codings <em class="bcp14">MUST</em> be listed in the order in which they were applied. Additional information about the encoding parameters <em class="bcp14">MAY</em> be provided by other entity-header fields not defined by this specification. |
|---|
| 1142 | </p> |
|---|
| 1143 | <div id="rfc.iref.c.3"></div> |
|---|
| 1144 | <div id="rfc.iref.h.6"></div> |
|---|
| 1145 | <h2 id="rfc.section.6.6"><a href="#rfc.section.6.6">6.6</a> <a id="header.content-language" href="#header.content-language">Content-Language</a></h2> |
|---|
| 1146 | <p id="rfc.section.6.6.p.1">The Content-Language entity-header field describes the natural language(s) of the intended audience for the enclosed entity. |
|---|
| 1147 | Note that this might not be equivalent to all the languages used within the entity-body. |
|---|
| 1148 | </p> |
|---|
| 1149 | <div id="rfc.figure.u.32"></div><pre class="inline"><span id="rfc.iref.g.27"></span> <a href="#header.content-language" class="smpl">Content-Language</a> = "Content-Language" ":" 1#<a href="#language.tags" class="smpl">language-tag</a> |
|---|
| 1150 | </pre><p id="rfc.section.6.6.p.3">Language tags are defined in <a href="#language.tags" title="Language Tags">Section 3.5</a>. The primary purpose of Content-Language is to allow a user to identify and differentiate entities according to the user's |
|---|
| 1151 | own preferred language. Thus, if the body content is intended only for a Danish-literate audience, the appropriate field is |
|---|
| 1152 | </p> |
|---|
| 1153 | <div id="rfc.figure.u.33"></div><pre class="text"> Content-Language: da |
|---|
| 1154 | </pre><p id="rfc.section.6.6.p.5">If no Content-Language is specified, the default is that the content is intended for all language audiences. This might mean |
|---|
| 1155 | that the sender does not consider it to be specific to any natural language, or that the sender does not know for which language |
|---|
| 1156 | it is intended. |
|---|
| 1157 | </p> |
|---|
| 1158 | <p id="rfc.section.6.6.p.6">Multiple languages <em class="bcp14">MAY</em> be listed for content that is intended for multiple audiences. For example, a rendition of the "Treaty of Waitangi," presented |
|---|
| 1159 | simultaneously in the original Maori and English versions, would call for |
|---|
| 1160 | </p> |
|---|
| 1161 | <div id="rfc.figure.u.34"></div><pre class="text"> Content-Language: mi, en |
|---|
| 1162 | </pre><p id="rfc.section.6.6.p.8">However, just because multiple languages are present within an entity does not mean that it is intended for multiple linguistic |
|---|
| 1163 | audiences. An example would be a beginner's language primer, such as "A First Lesson in Latin," which is clearly intended |
|---|
| 1164 | to be used by an English-literate audience. In this case, the Content-Language would properly only include "en". |
|---|
| 1165 | </p> |
|---|
| 1166 | <p id="rfc.section.6.6.p.9">Content-Language <em class="bcp14">MAY</em> be applied to any media type -- it is not limited to textual documents. |
|---|
| 1167 | </p> |
|---|
| 1168 | <div id="rfc.iref.c.4"></div> |
|---|
| 1169 | <div id="rfc.iref.h.7"></div> |
|---|
| 1170 | <h2 id="rfc.section.6.7"><a href="#rfc.section.6.7">6.7</a> <a id="header.content-location" href="#header.content-location">Content-Location</a></h2> |
|---|
| 1171 | <p id="rfc.section.6.7.p.1">The Content-Location entity-header field <em class="bcp14">MAY</em> be used to supply the resource location for the entity enclosed in the message when that entity is accessible from a location |
|---|
| 1172 | separate from the requested resource's URI. A server <em class="bcp14">SHOULD</em> provide a Content-Location for the variant corresponding to the response entity; especially in the case where a resource has |
|---|
| 1173 | multiple entities associated with it, and those entities actually have separate locations by which they might be individually |
|---|
| 1174 | accessed, the server <em class="bcp14">SHOULD</em> provide a Content-Location for the particular variant which is returned. |
|---|
| 1175 | </p> |
|---|
| 1176 | <div id="rfc.figure.u.35"></div><pre class="inline"><span id="rfc.iref.g.28"></span> <a href="#header.content-location" class="smpl">Content-Location</a> = "Content-Location" ":" |
|---|
| 1177 | ( <a href="#abnf.dependencies" class="smpl">absoluteURI</a> | <a href="#abnf.dependencies" class="smpl">relativeURI</a> ) |
|---|
| 1178 | </pre><p id="rfc.section.6.7.p.3">The value of Content-Location also defines the base URI for the entity.</p> |
|---|
| 1179 | <p id="rfc.section.6.7.p.4">The Content-Location value is not a replacement for the original requested URI; it is only a statement of the location of |
|---|
| 1180 | the resource corresponding to this particular entity at the time of the request. Future requests <em class="bcp14">MAY</em> specify the Content-Location URI as the request-URI if the desire is to identify the source of that particular entity. |
|---|
| 1181 | </p> |
|---|
| 1182 | <p id="rfc.section.6.7.p.5">A cache cannot assume that an entity with a Content-Location different from the URI used to retrieve it can be used to respond |
|---|
| 1183 | to later requests on that Content-Location URI. However, the Content-Location can be used to differentiate between multiple |
|---|
| 1184 | entities retrieved from a single requested resource, as described in <a href="p6-cache.html#caching.negotiated.responses" title="Caching Negotiated Responses">Section 8</a> of <a href="#Part6" id="rfc.xref.Part6.4"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>. |
|---|
| 1185 | </p> |
|---|
| 1186 | <p id="rfc.section.6.7.p.6">If the Content-Location is a relative URI, the relative URI is interpreted relative to the Request-URI.</p> |
|---|
| 1187 | <p id="rfc.section.6.7.p.7">The meaning of the Content-Location header in PUT or POST requests is undefined; servers are free to ignore it in those cases.</p> |
|---|
| 1188 | <div id="rfc.iref.c.5"></div> |
|---|
| 1189 | <div id="rfc.iref.h.8"></div> |
|---|
| 1190 | <h2 id="rfc.section.6.8"><a href="#rfc.section.6.8">6.8</a> <a id="header.content-md5" href="#header.content-md5">Content-MD5</a></h2> |
|---|
| 1191 | <p id="rfc.section.6.8.p.1">The Content-MD5 entity-header field, as defined in <a href="#RFC1864" id="rfc.xref.RFC1864.1"><cite title="The Content-MD5 Header Field">[RFC1864]</cite></a>, is an MD5 digest of the entity-body for the purpose of providing an end-to-end message integrity check (MIC) of the entity-body. |
|---|
| 1192 | (Note: a MIC is good for detecting accidental modification of the entity-body in transit, but is not proof against malicious |
|---|
| 1193 | attacks.) |
|---|
| 1194 | </p> |
|---|
| 1195 | <div id="rfc.figure.u.36"></div><pre class="inline"><span id="rfc.iref.g.29"></span><span id="rfc.iref.g.30"></span> <a href="#header.content-md5" class="smpl">Content-MD5</a> = "Content-MD5" ":" <a href="#header.content-md5" class="smpl">md5-digest</a> |
|---|
| 1196 | <a href="#header.content-md5" class="smpl">md5-digest</a> = <base64 of 128 bit MD5 digest as per <a href="#RFC1864" id="rfc.xref.RFC1864.2"><cite title="The Content-MD5 Header Field">[RFC1864]</cite></a>> |
|---|
| 1197 | </pre><p id="rfc.section.6.8.p.3">The Content-MD5 header field <em class="bcp14">MAY</em> be generated by an origin server or client to function as an integrity check of the entity-body. Only origin servers or clients <em class="bcp14">MAY</em> generate the Content-MD5 header field; proxies and gateways <em class="bcp14">MUST NOT</em> generate it, as this would defeat its value as an end-to-end integrity check. Any recipient of the entity-body, including |
|---|
| 1198 | gateways and proxies, <em class="bcp14">MAY</em> check that the digest value in this header field matches that of the entity-body as received. |
|---|
| 1199 | </p> |
|---|
| 1200 | <p id="rfc.section.6.8.p.4">The MD5 digest is computed based on the content of the entity-body, including any content-coding that has been applied, but |
|---|
| 1201 | not including any transfer-encoding applied to the message-body. If the message is received with a transfer-encoding, that |
|---|
| 1202 | encoding <em class="bcp14">MUST</em> be removed prior to checking the Content-MD5 value against the received entity. |
|---|
| 1203 | </p> |
|---|
| 1204 | <p id="rfc.section.6.8.p.5">This has the result that the digest is computed on the octets of the entity-body exactly as, and in the order that, they would |
|---|
| 1205 | be sent if no transfer-encoding were being applied. |
|---|
| 1206 | </p> |
|---|
| 1207 | <p id="rfc.section.6.8.p.6">HTTP extends RFC 1864 to permit the digest to be computed for MIME composite media-types (e.g., multipart/* and message/rfc822), |
|---|
| 1208 | but this does not change how the digest is computed as defined in the preceding paragraph. |
|---|
| 1209 | </p> |
|---|
| 1210 | <p id="rfc.section.6.8.p.7">There are several consequences of this. The entity-body for composite types <em class="bcp14">MAY</em> contain many body-parts, each with its own MIME and HTTP headers (including Content-MD5, Content-Transfer-Encoding, and Content-Encoding |
|---|
| 1211 | headers). If a body-part has a Content-Transfer-Encoding or Content-Encoding header, it is assumed that the content of the |
|---|
| 1212 | body-part has had the encoding applied, and the body-part is included in the Content-MD5 digest as is -- i.e., after the application. |
|---|
| 1213 | The Transfer-Encoding header field is not allowed within body-parts. |
|---|
| 1214 | </p> |
|---|
| 1215 | <p id="rfc.section.6.8.p.8">Conversion of all line breaks to CRLF <em class="bcp14">MUST NOT</em> be done before computing or checking the digest: the line break convention used in the text actually transmitted <em class="bcp14">MUST</em> be left unaltered when computing the digest. |
|---|
| 1216 | </p> |
|---|
| 1217 | <dl class="empty"> |
|---|
| 1218 | <dd> <b>Note:</b> while the definition of Content-MD5 is exactly the same for HTTP as in RFC 1864 for MIME entity-bodies, there are several |
|---|
| 1219 | ways in which the application of Content-MD5 to HTTP entity-bodies differs from its application to MIME entity-bodies. One |
|---|
| 1220 | is that HTTP, unlike MIME, does not use Content-Transfer-Encoding, and does use Transfer-Encoding and Content-Encoding. Another |
|---|
| 1221 | is that HTTP more frequently uses binary content types than MIME, so it is worth noting that, in such cases, the byte order |
|---|
| 1222 | used to compute the digest is the transmission byte order defined for the type. Lastly, HTTP allows transmission of text types |
|---|
| 1223 | with any of several line break conventions and not just the canonical form using CRLF. |
|---|
| 1224 | </dd> |
|---|
| 1225 | </dl> |
|---|
| 1226 | <div id="rfc.iref.c.6"></div> |
|---|
| 1227 | <div id="rfc.iref.h.9"></div> |
|---|
| 1228 | <h2 id="rfc.section.6.9"><a href="#rfc.section.6.9">6.9</a> <a id="header.content-type" href="#header.content-type">Content-Type</a></h2> |
|---|
| 1229 | <p id="rfc.section.6.9.p.1">The Content-Type entity-header field indicates the media type of the entity-body sent to the recipient or, in the case of |
|---|
| 1230 | the HEAD method, the media type that would have been sent had the request been a GET. |
|---|
| 1231 | </p> |
|---|
| 1232 | <div id="rfc.figure.u.37"></div><pre class="inline"><span id="rfc.iref.g.31"></span> <a href="#header.content-type" class="smpl">Content-Type</a> = "Content-Type" ":" <a href="#media.types" class="smpl">media-type</a> |
|---|
| 1233 | </pre><p id="rfc.section.6.9.p.3">Media types are defined in <a href="#media.types" title="Media Types">Section 3.3</a>. An example of the field is |
|---|
| 1234 | </p> |
|---|
| 1235 | <div id="rfc.figure.u.38"></div><pre class="text"> Content-Type: text/html; charset=ISO-8859-4 |
|---|
| 1236 | </pre><p id="rfc.section.6.9.p.5">Further discussion of methods for identifying the media type of an entity is provided in <a href="#type" title="Type">Section 4.2.1</a>. |
|---|
| 1237 | </p> |
|---|
| 1238 | <h1 id="rfc.section.7"><a href="#rfc.section.7">7.</a> <a id="IANA.considerations" href="#IANA.considerations">IANA Considerations</a></h1> |
|---|
| 1239 | <h2 id="rfc.section.7.1"><a href="#rfc.section.7.1">7.1</a> <a id="message.header.registration" href="#message.header.registration">Message Header Registration</a></h2> |
|---|
| 1240 | <p id="rfc.section.7.1.p.1">The Message Header Registry located at <<a href="http://www.iana.org/assignments/message-headers/message-header-index.html">http://www.iana.org/assignments/message-headers/message-header-index.html</a>> should be updated with the permanent registrations below (see <a href="#RFC3864" id="rfc.xref.RFC3864.1"><cite title="Registration Procedures for Message Header Fields">[RFC3864]</cite></a>): |
|---|
| 1241 | </p> |
|---|
| 1242 | <div id="rfc.table.u.1"> |
|---|
| 1243 | <table summary="" class="tt full" cellpadding="3" cellspacing="0"> |
|---|
| 1244 | <thead> |
|---|
| 1245 | <tr> |
|---|
| 1246 | <th>Header Field Name</th> |
|---|
| 1247 | <th>Protocol</th> |
|---|
| 1248 | <th>Status</th> |
|---|
| 1249 | <th>Reference</th> |
|---|
| 1250 | </tr> |
|---|
| 1251 | </thead> |
|---|
| 1252 | <tbody> |
|---|
| 1253 | <tr> |
|---|
| 1254 | <td>Accept</td> |
|---|
| 1255 | <td>http</td> |
|---|
| 1256 | <td>standard</td> |
|---|
| 1257 | <td> <a href="#header.accept" id="rfc.xref.header.accept.3" title="Accept">Section 6.1</a> |
|---|
| 1258 | </td> |
|---|
| 1259 | </tr> |
|---|
| 1260 | <tr> |
|---|
| 1261 | <td>Accept-Charset</td> |
|---|
| 1262 | <td>http</td> |
|---|
| 1263 | <td>standard</td> |
|---|
| 1264 | <td> <a href="#header.accept-charset" id="rfc.xref.header.accept-charset.2" title="Accept-Charset">Section 6.2</a> |
|---|
| 1265 | </td> |
|---|
| 1266 | </tr> |
|---|
| 1267 | <tr> |
|---|
| 1268 | <td>Accept-Encoding</td> |
|---|
| 1269 | <td>http</td> |
|---|
| 1270 | <td>standard</td> |
|---|
| 1271 | <td> <a href="#header.accept-encoding" id="rfc.xref.header.accept-encoding.3" title="Accept-Encoding">Section 6.3</a> |
|---|
| 1272 | </td> |
|---|
| 1273 | </tr> |
|---|
| 1274 | <tr> |
|---|
| 1275 | <td>Accept-Language</td> |
|---|
| 1276 | <td>http</td> |
|---|
| 1277 | <td>standard</td> |
|---|
| 1278 | <td> <a href="#header.accept-language" id="rfc.xref.header.accept-language.2" title="Accept-Language">Section 6.4</a> |
|---|
| 1279 | </td> |
|---|
| 1280 | </tr> |
|---|
| 1281 | <tr> |
|---|
| 1282 | <td>Content-Disposition</td> |
|---|
| 1283 | <td>http</td> |
|---|
| 1284 | <td> </td> |
|---|
| 1285 | <td> <a href="#content-disposition" id="rfc.xref.content-disposition.1" title="Content-Disposition">Appendix B.1</a> |
|---|
| 1286 | </td> |
|---|
| 1287 | </tr> |
|---|
| 1288 | <tr> |
|---|
| 1289 | <td>Content-Encoding</td> |
|---|
| 1290 | <td>http</td> |
|---|
| 1291 | <td>standard</td> |
|---|
| 1292 | <td> <a href="#header.content-encoding" id="rfc.xref.header.content-encoding.4" title="Content-Encoding">Section 6.5</a> |
|---|
| 1293 | </td> |
|---|
| 1294 | </tr> |
|---|
| 1295 | <tr> |
|---|
| 1296 | <td>Content-Language</td> |
|---|
| 1297 | <td>http</td> |
|---|
| 1298 | <td>standard</td> |
|---|
| 1299 | <td> <a href="#header.content-language" id="rfc.xref.header.content-language.2" title="Content-Language">Section 6.6</a> |
|---|
| 1300 | </td> |
|---|
| 1301 | </tr> |
|---|
| 1302 | <tr> |
|---|
| 1303 | <td>Content-Location</td> |
|---|
| 1304 | <td>http</td> |
|---|
| 1305 | <td>standard</td> |
|---|
| 1306 | <td> <a href="#header.content-location" id="rfc.xref.header.content-location.2" title="Content-Location">Section 6.7</a> |
|---|
| 1307 | </td> |
|---|
| 1308 | </tr> |
|---|
| 1309 | <tr> |
|---|
| 1310 | <td>Content-MD5</td> |
|---|
| 1311 | <td>http</td> |
|---|
| 1312 | <td>standard</td> |
|---|
| 1313 | <td> <a href="#header.content-md5" id="rfc.xref.header.content-md5.2" title="Content-MD5">Section 6.8</a> |
|---|
| 1314 | </td> |
|---|
| 1315 | </tr> |
|---|
| 1316 | <tr> |
|---|
| 1317 | <td>Content-Type</td> |
|---|
| 1318 | <td>http</td> |
|---|
| 1319 | <td>standard</td> |
|---|
| 1320 | <td> <a href="#header.content-type" id="rfc.xref.header.content-type.3" title="Content-Type">Section 6.9</a> |
|---|
| 1321 | </td> |
|---|
| 1322 | </tr> |
|---|
| 1323 | </tbody> |
|---|
| 1324 | </table> |
|---|
| 1325 | </div> |
|---|
| 1326 | <p id="rfc.section.7.1.p.2">The change controller is: "IETF (iesg@ietf.org) - Internet Engineering Task Force".</p> |
|---|
| 1327 | <h1 id="rfc.section.8"><a href="#rfc.section.8">8.</a> <a id="security.considerations" href="#security.considerations">Security Considerations</a></h1> |
|---|
| 1328 | <p id="rfc.section.8.p.1">This section is meant to inform application developers, information providers, and users of the security limitations in HTTP/1.1 |
|---|
| 1329 | as described by this document. The discussion does not include definitive solutions to the problems revealed, though it does |
|---|
| 1330 | make some suggestions for reducing security risks. |
|---|
| 1331 | </p> |
|---|
| 1332 | <h2 id="rfc.section.8.1"><a href="#rfc.section.8.1">8.1</a> <a id="privacy.issues.connected.to.accept.headers" href="#privacy.issues.connected.to.accept.headers">Privacy Issues Connected to Accept Headers</a></h2> |
|---|
| 1333 | <p id="rfc.section.8.1.p.1">Accept request-headers can reveal information about the user to all servers which are accessed. The Accept-Language header |
|---|
| 1334 | in particular can reveal information the user would consider to be of a private nature, because the understanding of particular |
|---|
| 1335 | languages is often strongly correlated to the membership of a particular ethnic group. User agents which offer the option |
|---|
| 1336 | to configure the contents of an Accept-Language header to be sent in every request are strongly encouraged to let the configuration |
|---|
| 1337 | process include a message which makes the user aware of the loss of privacy involved. |
|---|
| 1338 | </p> |
|---|
| 1339 | <p id="rfc.section.8.1.p.2">An approach that limits the loss of privacy would be for a user agent to omit the sending of Accept-Language headers by default, |
|---|
| 1340 | and to ask the user whether or not to start sending Accept-Language headers to a server if it detects, by looking for any |
|---|
| 1341 | Vary response-header fields generated by the server, that such sending could improve the quality of service. |
|---|
| 1342 | </p> |
|---|
| 1343 | <p id="rfc.section.8.1.p.3">Elaborate user-customized accept header fields sent in every request, in particular if these include quality values, can be |
|---|
| 1344 | used by servers as relatively reliable and long-lived user identifiers. Such user identifiers would allow content providers |
|---|
| 1345 | to do click-trail tracking, and would allow collaborating content providers to match cross-server click-trails or form submissions |
|---|
| 1346 | of individual users. Note that for many users not behind a proxy, the network address of the host running the user agent will |
|---|
| 1347 | also serve as a long-lived user identifier. In environments where proxies are used to enhance privacy, user agents ought to |
|---|
| 1348 | be conservative in offering accept header configuration options to end users. As an extreme privacy measure, proxies could |
|---|
| 1349 | filter the accept headers in relayed requests. General purpose user agents which provide a high degree of header configurability <em class="bcp14">SHOULD</em> warn users about the loss of privacy which can be involved. |
|---|
| 1350 | </p> |
|---|
| 1351 | <h2 id="rfc.section.8.2"><a href="#rfc.section.8.2">8.2</a> <a id="content-disposition.issues" href="#content-disposition.issues">Content-Disposition Issues</a></h2> |
|---|
| 1352 | <p id="rfc.section.8.2.p.1"> <a href="#RFC2183" id="rfc.xref.RFC2183.1"><cite title="Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field">[RFC2183]</cite></a>, from which the often implemented Content-Disposition (see <a href="#content-disposition" id="rfc.xref.content-disposition.2" title="Content-Disposition">Appendix B.1</a>) header in HTTP is derived, has a number of very serious security considerations. Content-Disposition is not part of the |
|---|
| 1353 | HTTP standard, but since it is widely implemented, we are documenting its use and risks for implementors. See <a href="http://tools.ietf.org/html/rfc2183#section-5">Section 5</a> of <a href="#RFC2183" id="rfc.xref.RFC2183.2"><cite title="Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field">[RFC2183]</cite></a> for details. |
|---|
| 1354 | </p> |
|---|
| 1355 | <h1 id="rfc.section.9"><a href="#rfc.section.9">9.</a> <a id="ack" href="#ack">Acknowledgments</a></h1> |
|---|
| 1356 | <h1 id="rfc.references"><a id="rfc.section.10" href="#rfc.section.10">10.</a> References |
|---|
| 1357 | </h1> |
|---|
| 1358 | <h2 id="rfc.references.1"><a href="#rfc.section.10.1" id="rfc.section.10.1">10.1</a> Normative References |
|---|
| 1359 | </h2> |
|---|
| 1360 | <table summary="Normative References"> |
|---|
| 1361 | <tr> |
|---|
| 1362 | <td class="reference"><b id="ISO-8859-1">[ISO-8859-1]</b></td> |
|---|
| 1363 | <td class="top">International Organization for Standardization, “ |
|---|
| 1364 | Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1 |
|---|
| 1365 | ”, ISO/IEC 8859-1:1998, 1998. |
|---|
| 1366 | </td> |
|---|
| 1367 | </tr> |
|---|
| 1368 | <tr> |
|---|
| 1369 | <td class="reference"><b id="Part1">[Part1]</b></td> |
|---|
| 1370 | <td class="top"><a title="Day Software">Fielding, R., Ed.</a>, <a title="One Laptop per Child">Gettys, J.</a>, <a title="Hewlett-Packard Company">Mogul, J.</a>, <a title="Microsoft Corporation">Frystyk, H.</a>, <a title="Adobe Systems, Incorporated">Masinter, L.</a>, <a title="Microsoft Corporation">Leach, P.</a>, <a title="World Wide Web Consortium">Berners-Lee, T.</a>, <a title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a title="greenbytes GmbH">J. F. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p1-messaging-latest">HTTP/1.1, part 1: URIs, Connections, and Message Parsing</a>”, Internet-Draft draft-ietf-httpbis-p1-messaging-latest (work in progress), July 2008. |
|---|
| 1371 | </td> |
|---|
| 1372 | </tr> |
|---|
| 1373 | <tr> |
|---|
| 1374 | <td class="reference"><b id="Part2">[Part2]</b></td> |
|---|
| 1375 | <td class="top"><a title="Day Software">Fielding, R., Ed.</a>, <a title="One Laptop per Child">Gettys, J.</a>, <a title="Hewlett-Packard Company">Mogul, J.</a>, <a title="Microsoft Corporation">Frystyk, H.</a>, <a title="Adobe Systems, Incorporated">Masinter, L.</a>, <a title="Microsoft Corporation">Leach, P.</a>, <a title="World Wide Web Consortium">Berners-Lee, T.</a>, <a title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a title="greenbytes GmbH">J. F. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-latest">HTTP/1.1, part 2: Message Semantics</a>”, Internet-Draft draft-ietf-httpbis-p2-semantics-latest (work in progress), July 2008. |
|---|
| 1376 | </td> |
|---|
| 1377 | </tr> |
|---|
| 1378 | <tr> |
|---|
| 1379 | <td class="reference"><b id="Part4">[Part4]</b></td> |
|---|
| 1380 | <td class="top"><a title="Day Software">Fielding, R., Ed.</a>, <a title="One Laptop per Child">Gettys, J.</a>, <a title="Hewlett-Packard Company">Mogul, J.</a>, <a title="Microsoft Corporation">Frystyk, H.</a>, <a title="Adobe Systems, Incorporated">Masinter, L.</a>, <a title="Microsoft Corporation">Leach, P.</a>, <a title="World Wide Web Consortium">Berners-Lee, T.</a>, <a title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a title="greenbytes GmbH">J. F. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p4-conditional-latest">HTTP/1.1, part 4: Conditional Requests</a>”, Internet-Draft draft-ietf-httpbis-p4-conditional-latest (work in progress), July 2008. |
|---|
| 1381 | </td> |
|---|
| 1382 | </tr> |
|---|
| 1383 | <tr> |
|---|
| 1384 | <td class="reference"><b id="Part5">[Part5]</b></td> |
|---|
| 1385 | <td class="top"><a title="Day Software">Fielding, R., Ed.</a>, <a title="One Laptop per Child">Gettys, J.</a>, <a title="Hewlett-Packard Company">Mogul, J.</a>, <a title="Microsoft Corporation">Frystyk, H.</a>, <a title="Adobe Systems, Incorporated">Masinter, L.</a>, <a title="Microsoft Corporation">Leach, P.</a>, <a title="World Wide Web Consortium">Berners-Lee, T.</a>, <a title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a title="greenbytes GmbH">J. F. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p5-range-latest">HTTP/1.1, part 5: Range Requests and Partial Responses</a>”, Internet-Draft draft-ietf-httpbis-p5-range-latest (work in progress), July 2008. |
|---|
| 1386 | </td> |
|---|
| 1387 | </tr> |
|---|
| 1388 | <tr> |
|---|
| 1389 | <td class="reference"><b id="Part6">[Part6]</b></td> |
|---|
| 1390 | <td class="top"><a title="Day Software">Fielding, R., Ed.</a>, <a title="One Laptop per Child">Gettys, J.</a>, <a title="Hewlett-Packard Company">Mogul, J.</a>, <a title="Microsoft Corporation">Frystyk, H.</a>, <a title="Adobe Systems, Incorporated">Masinter, L.</a>, <a title="Microsoft Corporation">Leach, P.</a>, <a title="World Wide Web Consortium">Berners-Lee, T.</a>, <a title="World Wide Web Consortium">Lafon, Y., Ed.</a>, and <a title="greenbytes GmbH">J. F. Reschke, Ed.</a>, “<a href="http://tools.ietf.org/html/draft-ietf-httpbis-p6-cache-latest">HTTP/1.1, part 6: Caching</a>”, Internet-Draft draft-ietf-httpbis-p6-cache-latest (work in progress), July 2008. |
|---|
| 1391 | </td> |
|---|
| 1392 | </tr> |
|---|
| 1393 | <tr> |
|---|
| 1394 | <td class="reference"><b id="RFC1766">[RFC1766]</b></td> |
|---|
| 1395 | <td class="top"><a title="UNINETT">Alvestrand, H.</a>, “<a href="http://tools.ietf.org/html/rfc1766">Tags for the Identification of Languages</a>”, RFC 1766, March 1995. |
|---|
| 1396 | </td> |
|---|
| 1397 | </tr> |
|---|
| 1398 | <tr> |
|---|
| 1399 | <td class="reference"><b id="RFC1864">[RFC1864]</b></td> |
|---|
| 1400 | <td class="top"><a title="Carnegie Mellon University">Myers, J.</a> and <a title="Dover Beach Consulting, Inc.">M. Rose</a>, “<a href="http://tools.ietf.org/html/rfc1864">The Content-MD5 Header Field</a>”, RFC 1864, October 1995. |
|---|
| 1401 | </td> |
|---|
| 1402 | </tr> |
|---|
| 1403 | <tr> |
|---|
| 1404 | <td class="reference"><b id="RFC1950">[RFC1950]</b></td> |
|---|
| 1405 | <td class="top"><a title="Aladdin Enterprises">Deutsch, L.P.</a> and J-L. Gailly, “<a href="http://tools.ietf.org/html/rfc1950">ZLIB Compressed Data Format Specification version 3.3</a>”, RFC 1950, May 1996.<br>RFC1950 is an Informational RFC, thus it may be less stable than this specification. On the other hand, this downward reference |
|---|
| 1406 | was present since <a href="#RFC2068" id="rfc.xref.RFC2068.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> (published in 1997), therefore it is unlikely to cause problems in practice. |
|---|
| 1407 | </td> |
|---|
| 1408 | </tr> |
|---|
| 1409 | <tr> |
|---|
| 1410 | <td class="reference"><b id="RFC1951">[RFC1951]</b></td> |
|---|
| 1411 | <td class="top"><a title="Aladdin Enterprises">Deutsch, P.</a>, “<a href="http://tools.ietf.org/html/rfc1951">DEFLATE Compressed Data Format Specification version 1.3</a>”, RFC 1951, May 1996.<br>RFC1951 is an Informational RFC, thus it may be less stable than this specification. On the other hand, this downward reference |
|---|
| 1412 | was present since <a href="#RFC2068" id="rfc.xref.RFC2068.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> (published in 1997), therefore it is unlikely to cause problems in practice. |
|---|
| 1413 | </td> |
|---|
| 1414 | </tr> |
|---|
| 1415 | <tr> |
|---|
| 1416 | <td class="reference"><b id="RFC1952">[RFC1952]</b></td> |
|---|
| 1417 | <td class="top"><a title="Aladdin Enterprises">Deutsch, P.</a>, <a>Gailly, J-L.</a>, <a>Adler, M.</a>, <a>Deutsch, L.P.</a>, and <a>G. Randers-Pehrson</a>, “<a href="http://tools.ietf.org/html/rfc1952">GZIP file format specification version 4.3</a>”, RFC 1952, May 1996.<br>RFC1952 is an Informational RFC, thus it may be less stable than this specification. On the other hand, this downward reference |
|---|
| 1418 | was present since <a href="#RFC2068" id="rfc.xref.RFC2068.3"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> (published in 1997), therefore it is unlikely to cause problems in practice. |
|---|
| 1419 | </td> |
|---|
| 1420 | </tr> |
|---|
| 1421 | <tr> |
|---|
| 1422 | <td class="reference"><b id="RFC2045">[RFC2045]</b></td> |
|---|
| 1423 | <td class="top"><a title="Innosoft International, Inc.">Freed, N.</a> and <a title="First Virtual Holdings">N.S. Borenstein</a>, “<a href="http://tools.ietf.org/html/rfc2045">Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies</a>”, RFC 2045, November 1996. |
|---|
| 1424 | </td> |
|---|
| 1425 | </tr> |
|---|
| 1426 | <tr> |
|---|
| 1427 | <td class="reference"><b id="RFC2046">[RFC2046]</b></td> |
|---|
| 1428 | <td class="top"><a title="Innosoft International, Inc.">Freed, N.</a> and <a title="First Virtual Holdings">N. Borenstein</a>, “<a href="http://tools.ietf.org/html/rfc2046">Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types</a>”, RFC 2046, November 1996. |
|---|
| 1429 | </td> |
|---|
| 1430 | </tr> |
|---|
| 1431 | <tr> |
|---|
| 1432 | <td class="reference"><b id="RFC2119">[RFC2119]</b></td> |
|---|
| 1433 | <td class="top"><a title="Harvard University">Bradner, S.</a>, “<a href="http://tools.ietf.org/html/rfc2119">Key words for use in RFCs to Indicate Requirement Levels</a>”, BCP 14, RFC 2119, March 1997. |
|---|
| 1434 | </td> |
|---|
| 1435 | </tr> |
|---|
| 1436 | </table> |
|---|
| 1437 | <h2 id="rfc.references.2"><a href="#rfc.section.10.2" id="rfc.section.10.2">10.2</a> Informative References |
|---|
| 1438 | </h2> |
|---|
| 1439 | <table summary="Informative References"> |
|---|
| 1440 | <tr> |
|---|
| 1441 | <td class="reference"><b id="RFC1945">[RFC1945]</b></td> |
|---|
| 1442 | <td class="top"><a title="MIT, Laboratory for Computer Science">Berners-Lee, T.</a>, <a title="University of California, Irvine, Department of Information and Computer Science">Fielding, R.T.</a>, and <a title="W3 Consortium, MIT Laboratory for Computer Science">H.F. Nielsen</a>, “<a href="http://tools.ietf.org/html/rfc1945">Hypertext Transfer Protocol -- HTTP/1.0</a>”, RFC 1945, May 1996. |
|---|
| 1443 | </td> |
|---|
| 1444 | </tr> |
|---|
| 1445 | <tr> |
|---|
| 1446 | <td class="reference"><b id="RFC2049">[RFC2049]</b></td> |
|---|
| 1447 | <td class="top"><a title="Innosoft International, Inc.">Freed, N.</a> and <a title="First Virtual Holdings">N.S. Borenstein</a>, “<a href="http://tools.ietf.org/html/rfc2049">Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples</a>”, RFC 2049, November 1996. |
|---|
| 1448 | </td> |
|---|
| 1449 | </tr> |
|---|
| 1450 | <tr> |
|---|
| 1451 | <td class="reference"><b id="RFC2068">[RFC2068]</b></td> |
|---|
| 1452 | <td class="top"><a title="University of California, Irvine, Department of Information and Computer Science">Fielding, R.</a>, <a title="MIT Laboratory for Computer Science">Gettys, J.</a>, <a title="Digital Equipment Corporation, Western Research Laboratory">Mogul, J.</a>, <a title="MIT Laboratory for Computer Science">Nielsen, H.</a>, and <a title="MIT Laboratory for Computer Science">T. Berners-Lee</a>, “<a href="http://tools.ietf.org/html/rfc2068">Hypertext Transfer Protocol -- HTTP/1.1</a>”, RFC 2068, January 1997. |
|---|
| 1453 | </td> |
|---|
| 1454 | </tr> |
|---|
| 1455 | <tr> |
|---|
| 1456 | <td class="reference"><b id="RFC2076">[RFC2076]</b></td> |
|---|
| 1457 | <td class="top"><a title="Stockholm University/KTH">Palme, J.</a>, “<a href="http://tools.ietf.org/html/rfc2076">Common Internet Message Headers</a>”, RFC 2076, February 1997. |
|---|
| 1458 | </td> |
|---|
| 1459 | </tr> |
|---|
| 1460 | <tr> |
|---|
| 1461 | <td class="reference"><b id="RFC2183">[RFC2183]</b></td> |
|---|
| 1462 | <td class="top"><a title="New Century Systems">Troost, R.</a>, <a title="QUALCOMM Incorporated">Dorner, S.</a>, and <a title="Department of Computer Science">K. Moore</a>, “<a href="http://tools.ietf.org/html/rfc2183">Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field</a>”, RFC 2183, August 1997. |
|---|
| 1463 | </td> |
|---|
| 1464 | </tr> |
|---|
| 1465 | <tr> |
|---|
| 1466 | <td class="reference"><b id="RFC2277">[RFC2277]</b></td> |
|---|
| 1467 | <td class="top"><a title="UNINETT">Alvestrand, H.T.</a>, “<a href="http://tools.ietf.org/html/rfc2277">IETF Policy on Character Sets and Languages</a>”, BCP 18, RFC 2277, January 1998. |
|---|
| 1468 | </td> |
|---|
| 1469 | </tr> |
|---|
| 1470 | <tr> |
|---|
| 1471 | <td class="reference"><b id="RFC2388">[RFC2388]</b></td> |
|---|
| 1472 | <td class="top"><a title="Xerox Palo Alto Research Center">Masinter, L.</a>, “<a href="http://tools.ietf.org/html/rfc2388">Returning Values from Forms: multipart/form-data</a>”, RFC 2388, August 1998. |
|---|
| 1473 | </td> |
|---|
| 1474 | </tr> |
|---|
| 1475 | <tr> |
|---|
| 1476 | <td class="reference"><b id="RFC2557">[RFC2557]</b></td> |
|---|
| 1477 | <td class="top"><a title="Stockholm University and KTH">Palme, F.</a>, <a title="Microsoft Corporation">Hopmann, A.</a>, <a title="Lotus Development Corporation">Shelness, N.</a>, and <a>E. Stefferud</a>, “<a href="http://tools.ietf.org/html/rfc2557">MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)</a>”, RFC 2557, March 1999. |
|---|
| 1478 | </td> |
|---|
| 1479 | </tr> |
|---|
| 1480 | <tr> |
|---|
| 1481 | <td class="reference"><b id="RFC2616">[RFC2616]</b></td> |
|---|
| 1482 | <td class="top"><a title="University of California, Irvine">Fielding, R.</a>, <a title="W3C">Gettys, J.</a>, <a title="Compaq Computer Corporation">Mogul, J.</a>, <a title="MIT Laboratory for Computer Science">Frystyk, H.</a>, <a title="Xerox Corporation">Masinter, L.</a>, <a title="Microsoft Corporation">Leach, P.</a>, and <a title="W3C">T. Berners-Lee</a>, “<a href="http://tools.ietf.org/html/rfc2616">Hypertext Transfer Protocol -- HTTP/1.1</a>”, RFC 2616, June 1999. |
|---|
| 1483 | </td> |
|---|
| 1484 | </tr> |
|---|
| 1485 | <tr> |
|---|
| 1486 | <td class="reference"><b id="RFC2822">[RFC2822]</b></td> |
|---|
| 1487 | <td class="top">Resnick, P., “<a href="http://tools.ietf.org/html/rfc2822">Internet Message Format</a>”, RFC 2822, April 2001. |
|---|
| 1488 | </td> |
|---|
| 1489 | </tr> |
|---|
| 1490 | <tr> |
|---|
| 1491 | <td class="reference"><b id="RFC3629">[RFC3629]</b></td> |
|---|
| 1492 | <td class="top"><a title="Alis Technologies">Yergeau, F.</a>, “<a href="http://tools.ietf.org/html/rfc3629">UTF-8, a transformation format of ISO 10646</a>”, RFC 3629, STD 63, November 2003. |
|---|
| 1493 | </td> |
|---|
| 1494 | </tr> |
|---|
| 1495 | <tr> |
|---|
| 1496 | <td class="reference"><b id="RFC3864">[RFC3864]</b></td> |
|---|
| 1497 | <td class="top"><a title="Nine by Nine">Klyne, G.</a>, <a title="BEA Systems">Nottingham, M.</a>, and <a title="HP Labs">J. Mogul</a>, “<a href="http://tools.ietf.org/html/rfc3864">Registration Procedures for Message Header Fields</a>”, BCP 90, RFC 3864, September 2004. |
|---|
| 1498 | </td> |
|---|
| 1499 | </tr> |
|---|
| 1500 | <tr> |
|---|
| 1501 | <td class="reference"><b id="RFC4288">[RFC4288]</b></td> |
|---|
| 1502 | <td class="top"><a title="Sun Microsystems">Freed, N.</a> and <a>J. Klensin</a>, “<a href="http://tools.ietf.org/html/rfc4288">Media Type Specifications and Registration Procedures</a>”, BCP 13, RFC 4288, December 2005. |
|---|
| 1503 | </td> |
|---|
| 1504 | </tr> |
|---|
| 1505 | </table> |
|---|
| 1506 | <h1 id="rfc.authors"><a href="#rfc.authors">Authors' Addresses</a></h1> |
|---|
| 1507 | <address class="vcard"><span class="vcardline"><span class="fn">Roy T. Fielding</span> |
|---|
| 1508 | (editor) |
|---|
| 1509 | <span class="n hidden"><span class="family-name">Fielding</span><span class="given-name">Roy T.</span></span></span><span class="org vcardline">Day Software</span><span class="adr"><span class="street-address vcardline">23 Corporate Plaza DR, Suite 280</span><span class="vcardline"><span class="locality">Newport Beach</span>, <span class="region">CA</span> <span class="postal-code">92660</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline tel">Phone: <a href="tel:+1-949-706-5300"><span class="value">+1-949-706-5300</span></a></span><span class="vcardline tel"><span class="type">Fax</span>: <a href="fax:+1-949-706-5305"><span class="value">+1-949-706-5305</span></a></span><span class="vcardline">EMail: <a><span class="email">fielding@gbiv.com</span></a></span><span class="vcardline">URI: <a href="http://roy.gbiv.com/" class="url">http://roy.gbiv.com/</a></span></address> |
|---|
| 1510 | <address class="vcard"><span class="vcardline"><span class="fn">Jim Gettys</span><span class="n hidden"><span class="family-name">Gettys</span><span class="given-name">Jim</span></span></span><span class="org vcardline">One Laptop per Child</span><span class="adr"><span class="street-address vcardline">21 Oak Knoll Road</span><span class="vcardline"><span class="locality">Carlisle</span>, <span class="region">MA</span> <span class="postal-code">01741</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">EMail: <a><span class="email">jg@laptop.org</span></a></span><span class="vcardline">URI: <a href="http://www.laptop.org/" class="url">http://www.laptop.org/</a></span></address> |
|---|
| 1511 | <address class="vcard"><span class="vcardline"><span class="fn">Jeffrey C. Mogul</span><span class="n hidden"><span class="family-name">Mogul</span><span class="given-name">Jeffrey C.</span></span></span><span class="org vcardline">Hewlett-Packard Company</span><span class="adr"><span class="street-address vcardline">HP Labs, Large Scale Systems Group</span><span class="street-address vcardline">1501 Page Mill Road, MS 1177</span><span class="vcardline"><span class="locality">Palo Alto</span>, <span class="region">CA</span> <span class="postal-code">94304</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">EMail: <a><span class="email">JeffMogul@acm.org</span></a></span></address> |
|---|
| 1512 | <address class="vcard"><span class="vcardline"><span class="fn">Henrik Frystyk Nielsen</span><span class="n hidden"><span class="family-name">Frystyk</span></span></span><span class="org vcardline">Microsoft Corporation</span><span class="adr"><span class="street-address vcardline">1 Microsoft Way</span><span class="vcardline"><span class="locality">Redmond</span>, <span class="region">WA</span> <span class="postal-code">98052</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">EMail: <a><span class="email">henrikn@microsoft.com</span></a></span></address> |
|---|
| 1513 | <address class="vcard"><span class="vcardline"><span class="fn">Larry Masinter</span><span class="n hidden"><span class="family-name">Masinter</span><span class="given-name">Larry</span></span></span><span class="org vcardline">Adobe Systems, Incorporated</span><span class="adr"><span class="street-address vcardline">345 Park Ave</span><span class="vcardline"><span class="locality">San Jose</span>, <span class="region">CA</span> <span class="postal-code">95110</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">EMail: <a><span class="email">LMM@acm.org</span></a></span><span class="vcardline">URI: <a href="http://larry.masinter.net/" class="url">http://larry.masinter.net/</a></span></address> |
|---|
| 1514 | <address class="vcard"><span class="vcardline"><span class="fn">Paul J. Leach</span><span class="n hidden"><span class="family-name">Leach</span><span class="given-name">Paul J.</span></span></span><span class="org vcardline">Microsoft Corporation</span><span class="adr"><span class="street-address vcardline">1 Microsoft Way</span><span class="vcardline"><span class="locality">Redmond</span>, <span class="region">WA</span> <span class="postal-code">98052</span></span></span><span class="vcardline">EMail: <a><span class="email">paulle@microsoft.com</span></a></span></address> |
|---|
| 1515 | <address class="vcard"><span class="vcardline"><span class="fn">Tim Berners-Lee</span><span class="n hidden"><span class="family-name">Berners-Lee</span><span class="given-name">Tim</span></span></span><span class="org vcardline">World Wide Web Consortium</span><span class="adr"><span class="street-address vcardline">MIT Computer Science and Artificial Intelligence Laboratory</span><span class="street-address vcardline">The Stata Center, Building 32</span><span class="street-address vcardline">32 Vassar Street</span><span class="vcardline"><span class="locality">Cambridge</span>, <span class="region">MA</span> <span class="postal-code">02139</span></span><span class="country-name vcardline">USA</span></span><span class="vcardline">EMail: <a><span class="email">timbl@w3.org</span></a></span><span class="vcardline">URI: <a href="http://www.w3.org/People/Berners-Lee/" class="url">http://www.w3.org/People/Berners-Lee/</a></span></address> |
|---|
| 1516 | <address class="vcard"><span class="vcardline"><span class="fn">Yves Lafon</span> |
|---|
| 1517 | (editor) |
|---|
| 1518 | <span class="n hidden"><span class="family-name">Lafon</span><span class="given-name">Yves</span></span></span><span class="org vcardline">World Wide Web Consortium</span><span class="adr"><span class="street-address vcardline">W3C / ERCIM</span><span class="street-address vcardline">2004, rte des Lucioles</span><span class="vcardline"><span class="locality">Sophia-Antipolis</span>, <span class="region">AM</span> <span class="postal-code">06902</span></span><span class="country-name vcardline">France</span></span><span class="vcardline">EMail: <a><span class="email">ylafon@w3.org</span></a></span><span class="vcardline">URI: <a href="http://www.raubacapeu.net/people/yves/" class="url">http://www.raubacapeu.net/people/yves/</a></span></address> |
|---|
| 1519 | <address class="vcard"><span class="vcardline"><span class="fn">Julian F. Reschke</span> |
|---|
| 1520 | (editor) |
|---|
| 1521 | <span class="n hidden"><span class="family-name">Reschke</span><span class="given-name">Julian F.</span></span></span><span class="org vcardline">greenbytes GmbH</span><span class="adr"><span class="street-address vcardline">Hafenweg 16</span><span class="vcardline"><span class="locality">Muenster</span>, <span class="region">NW</span> <span class="postal-code">48155</span></span><span class="country-name vcardline">Germany</span></span><span class="vcardline tel">Phone: <a href="tel:+492512807760"><span class="value">+49 251 2807760</span></a></span><span class="vcardline tel"><span class="type">Fax</span>: <a href="fax:+492512807761"><span class="value">+49 251 2807761</span></a></span><span class="vcardline">EMail: <a><span class="email">julian.reschke@greenbytes.de</span></a></span><span class="vcardline">URI: <a href="http://greenbytes.de/tech/webdav/" class="url">http://greenbytes.de/tech/webdav/</a></span></address> |
|---|
| 1522 | <h1 id="rfc.section.A"><a href="#rfc.section.A">A.</a> <a id="differences.between.http.entities.and.rfc.2045.entities" href="#differences.between.http.entities.and.rfc.2045.entities">Differences Between HTTP Entities and RFC 2045 Entities</a></h1> |
|---|
| 1523 | <p id="rfc.section.A.p.1">HTTP/1.1 uses many of the constructs defined for Internet Mail (<a href="#RFC2822" id="rfc.xref.RFC2822.1"><cite title="Internet Message Format">[RFC2822]</cite></a>) and the Multipurpose Internet Mail Extensions (MIME <a href="#RFC2045" id="rfc.xref.RFC2045.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>) to allow entities to be transmitted in an open variety of representations and with extensible mechanisms. However, RFC 2045 |
|---|
| 1524 | discusses mail, and HTTP has a few features that are different from those described in RFC 2045. These differences were carefully |
|---|
| 1525 | chosen to optimize performance over binary connections, to allow greater freedom in the use of new media types, to make date |
|---|
| 1526 | comparisons easier, and to acknowledge the practice of some early HTTP servers and clients. |
|---|
| 1527 | </p> |
|---|
| 1528 | <p id="rfc.section.A.p.2">This appendix describes specific areas where HTTP differs from RFC 2045. Proxies and gateways to strict MIME environments <em class="bcp14">SHOULD</em> be aware of these differences and provide the appropriate conversions where necessary. Proxies and gateways from MIME environments |
|---|
| 1529 | to HTTP also need to be aware of the differences because some conversions might be required. |
|---|
| 1530 | </p> |
|---|
| 1531 | <h2 id="rfc.section.A.1"><a href="#rfc.section.A.1">A.1</a> <a id="mime-version" href="#mime-version">MIME-Version</a></h2> |
|---|
| 1532 | <p id="rfc.section.A.1.p.1">HTTP is not a MIME-compliant protocol. However, HTTP/1.1 messages <em class="bcp14">MAY</em> include a single MIME-Version general-header field to indicate what version of the MIME protocol was used to construct the |
|---|
| 1533 | message. Use of the MIME-Version header field indicates that the message is in full compliance with the MIME protocol (as |
|---|
| 1534 | defined in <a href="#RFC2045" id="rfc.xref.RFC2045.2"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a>). Proxies/gateways are responsible for ensuring full compliance (where possible) when exporting HTTP messages to strict MIME |
|---|
| 1535 | environments. |
|---|
| 1536 | </p> |
|---|
| 1537 | <div id="rfc.figure.u.39"></div><pre class="inline"><span id="rfc.iref.g.32"></span> <a href="#mime-version" class="smpl">MIME-Version</a> = "MIME-Version" ":" 1*<a href="#notation" class="smpl">DIGIT</a> "." 1*<a href="#notation" class="smpl">DIGIT</a> |
|---|
| 1538 | </pre><p id="rfc.section.A.1.p.3">MIME version "1.0" is the default for use in HTTP/1.1. However, HTTP/1.1 message parsing and semantics are defined by this |
|---|
| 1539 | document and not the MIME specification. |
|---|
| 1540 | </p> |
|---|
| 1541 | <h2 id="rfc.section.A.2"><a href="#rfc.section.A.2">A.2</a> <a id="conversion.to.canonical.form" href="#conversion.to.canonical.form">Conversion to Canonical Form</a></h2> |
|---|
| 1542 | <p id="rfc.section.A.2.p.1"> <a href="#RFC2045" id="rfc.xref.RFC2045.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part One: Format of Internet Message Bodies">[RFC2045]</cite></a> requires that an Internet mail entity be converted to canonical form prior to being transferred, as described in <a href="http://tools.ietf.org/html/rfc2049#section-4">Section 4</a> of <a href="#RFC2049" id="rfc.xref.RFC2049.1"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Five: Conformance Criteria and Examples">[RFC2049]</cite></a>. <a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Section 3.3.1</a> of this document describes the forms allowed for subtypes of the "text" media type when transmitted over HTTP. <a href="#RFC2046" id="rfc.xref.RFC2046.3"><cite title="Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types">[RFC2046]</cite></a> requires that content with a type of "text" represent line breaks as CRLF and forbids the use of CR or LF outside of line |
|---|
| 1543 | break sequences. HTTP allows CRLF, bare CR, and bare LF to indicate a line break within text content when a message is transmitted |
|---|
| 1544 | over HTTP. |
|---|
| 1545 | </p> |
|---|
| 1546 | <p id="rfc.section.A.2.p.2">Where it is possible, a proxy or gateway from HTTP to a strict MIME environment <em class="bcp14">SHOULD</em> translate all line breaks within the text media types described in <a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Section 3.3.1</a> of this document to the RFC 2049 canonical form of CRLF. Note, however, that this might be complicated by the presence of |
|---|
| 1547 | a Content-Encoding and by the fact that HTTP allows the use of some character sets which do not use octets 13 and 10 to represent |
|---|
| 1548 | CR and LF, as is the case for some multi-byte character sets. |
|---|
| 1549 | </p> |
|---|
| 1550 | <p id="rfc.section.A.2.p.3">Implementors should note that conversion will break any cryptographic checksums applied to the original content unless the |
|---|
| 1551 | original content is already in canonical form. Therefore, the canonical form is recommended for any content that uses such |
|---|
| 1552 | checksums in HTTP. |
|---|
| 1553 | </p> |
|---|
| 1554 | <h2 id="rfc.section.A.3"><a href="#rfc.section.A.3">A.3</a> <a id="introduction.of.content-encoding" href="#introduction.of.content-encoding">Introduction of Content-Encoding</a></h2> |
|---|
| 1555 | <p id="rfc.section.A.3.p.1">RFC 2045 does not include any concept equivalent to HTTP/1.1's Content-Encoding header field. Since this acts as a modifier |
|---|
| 1556 | on the media type, proxies and gateways from HTTP to MIME-compliant protocols <em class="bcp14">MUST</em> either change the value of the Content-Type header field or decode the entity-body before forwarding the message. (Some experimental |
|---|
| 1557 | applications of Content-Type for Internet mail have used a media-type parameter of ";conversions=<content-coding>" to perform |
|---|
| 1558 | a function equivalent to Content-Encoding. However, this parameter is not part of RFC 2045). |
|---|
| 1559 | </p> |
|---|
| 1560 | <h2 id="rfc.section.A.4"><a href="#rfc.section.A.4">A.4</a> <a id="no.content-transfer-encoding" href="#no.content-transfer-encoding">No Content-Transfer-Encoding</a></h2> |
|---|
| 1561 | <p id="rfc.section.A.4.p.1">HTTP does not use the Content-Transfer-Encoding field of RFC 2045. Proxies and gateways from MIME-compliant protocols to HTTP <em class="bcp14">MUST</em> remove any Content-Transfer-Encoding prior to delivering the response message to an HTTP client. |
|---|
| 1562 | </p> |
|---|
| 1563 | <p id="rfc.section.A.4.p.2">Proxies and gateways from HTTP to MIME-compliant protocols are responsible for ensuring that the message is in the correct |
|---|
| 1564 | format and encoding for safe transport on that protocol, where "safe transport" is defined by the limitations of the protocol |
|---|
| 1565 | being used. Such a proxy or gateway <em class="bcp14">SHOULD</em> label the data with an appropriate Content-Transfer-Encoding if doing so will improve the likelihood of safe transport over |
|---|
| 1566 | the destination protocol. |
|---|
| 1567 | </p> |
|---|
| 1568 | <h2 id="rfc.section.A.5"><a href="#rfc.section.A.5">A.5</a> <a id="introduction.of.transfer-encoding" href="#introduction.of.transfer-encoding">Introduction of Transfer-Encoding</a></h2> |
|---|
| 1569 | <p id="rfc.section.A.5.p.1">HTTP/1.1 introduces the Transfer-Encoding header field (<a href="p1-messaging.html#header.transfer-encoding" title="Transfer-Encoding">Section 8.7</a> of <a href="#Part1" id="rfc.xref.Part1.15"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>). Proxies/gateways <em class="bcp14">MUST</em> remove any transfer-coding prior to forwarding a message via a MIME-compliant protocol. |
|---|
| 1570 | </p> |
|---|
| 1571 | <h2 id="rfc.section.A.6"><a href="#rfc.section.A.6">A.6</a> <a id="mhtml.line.length" href="#mhtml.line.length">MHTML and Line Length Limitations</a></h2> |
|---|
| 1572 | <p id="rfc.section.A.6.p.1">HTTP implementations which share code with MHTML <a href="#RFC2557" id="rfc.xref.RFC2557.1"><cite title="MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)">[RFC2557]</cite></a> implementations need to be aware of MIME line length limitations. Since HTTP does not have this limitation, HTTP does not |
|---|
| 1573 | fold long lines. MHTML messages being transported by HTTP follow all conventions of MHTML, including line length limitations |
|---|
| 1574 | and folding, canonicalization, etc., since HTTP transports all message-bodies as payload (see <a href="#multipart.types" title="Multipart Types">Section 3.3.2</a>) and does not interpret the content or any MIME header lines that might be contained therein. |
|---|
| 1575 | </p> |
|---|
| 1576 | <h1 id="rfc.section.B"><a href="#rfc.section.B">B.</a> <a id="additional.features" href="#additional.features">Additional Features</a></h1> |
|---|
| 1577 | <p id="rfc.section.B.p.1"> <a href="#RFC1945" id="rfc.xref.RFC1945.1"><cite title="Hypertext Transfer Protocol -- HTTP/1.0">[RFC1945]</cite></a> and <a href="#RFC2068" id="rfc.xref.RFC2068.4"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a> document protocol elements used by some existing HTTP implementations, but not consistently and correctly across most HTTP/1.1 |
|---|
| 1578 | applications. Implementors are advised to be aware of these features, but cannot rely upon their presence in, or interoperability |
|---|
| 1579 | with, other HTTP/1.1 applications. Some of these describe proposed experimental features, and some describe features that |
|---|
| 1580 | experimental deployment found lacking that are now addressed in the base HTTP/1.1 specification. |
|---|
| 1581 | </p> |
|---|
| 1582 | <p id="rfc.section.B.p.2">A number of other headers, such as Content-Disposition and Title, from SMTP and MIME are also often implemented (see <a href="#RFC2076" id="rfc.xref.RFC2076.1"><cite title="Common Internet Message Headers">[RFC2076]</cite></a>). |
|---|
| 1583 | </p> |
|---|
| 1584 | <div id="rfc.iref.h.10"></div> |
|---|
| 1585 | <div id="rfc.iref.c.7"></div> |
|---|
| 1586 | <h2 id="rfc.section.B.1"><a href="#rfc.section.B.1">B.1</a> <a id="content-disposition" href="#content-disposition">Content-Disposition</a></h2> |
|---|
| 1587 | <p id="rfc.section.B.1.p.1">The Content-Disposition response-header field has been proposed as a means for the origin server to suggest a default filename |
|---|
| 1588 | if the user requests that the content is saved to a file. This usage is derived from the definition of Content-Disposition |
|---|
| 1589 | in <a href="#RFC2183" id="rfc.xref.RFC2183.3"><cite title="Communicating Presentation Information in Internet Messages: The Content-Disposition Header Field">[RFC2183]</cite></a>. |
|---|
| 1590 | </p> |
|---|
| 1591 | <div id="rfc.figure.u.40"></div><pre class="inline"><span id="rfc.iref.g.33"></span><span id="rfc.iref.g.34"></span><span id="rfc.iref.g.35"></span><span id="rfc.iref.g.36"></span><span id="rfc.iref.g.37"></span><span id="rfc.iref.g.38"></span> <a href="#content-disposition" class="smpl">content-disposition</a> = "Content-Disposition" ":" |
|---|
| 1592 | <a href="#content-disposition" class="smpl">disposition-type</a> *( ";" <a href="#content-disposition" class="smpl">disposition-parm</a> ) |
|---|
| 1593 | <a href="#content-disposition" class="smpl">disposition-type</a> = "attachment" | <a href="#content-disposition" class="smpl">disp-extension-token</a> |
|---|
| 1594 | <a href="#content-disposition" class="smpl">disposition-parm</a> = <a href="#content-disposition" class="smpl">filename-parm</a> | <a href="#content-disposition" class="smpl">disp-extension-parm</a> |
|---|
| 1595 | <a href="#content-disposition" class="smpl">filename-parm</a> = "filename" "=" <a href="#notation" class="smpl">quoted-string</a> |
|---|
| 1596 | <a href="#content-disposition" class="smpl">disp-extension-token</a> = <a href="#notation" class="smpl">token</a> |
|---|
| 1597 | <a href="#content-disposition" class="smpl">disp-extension-parm</a> = <a href="#notation" class="smpl">token</a> "=" ( <a href="#notation" class="smpl">token</a> | <a href="#notation" class="smpl">quoted-string</a> ) |
|---|
| 1598 | </pre><p id="rfc.section.B.1.p.3">An example is</p> |
|---|
| 1599 | <div id="rfc.figure.u.41"></div><pre class="text"> Content-Disposition: attachment; filename="fname.ext" |
|---|
| 1600 | </pre><p id="rfc.section.B.1.p.5">The receiving user agent <em class="bcp14">SHOULD NOT</em> respect any directory path information present in the filename-parm parameter, which is the only parameter believed to apply |
|---|
| 1601 | to HTTP implementations at this time. The filename <em class="bcp14">SHOULD</em> be treated as a terminal component only. |
|---|
| 1602 | </p> |
|---|
| 1603 | <p id="rfc.section.B.1.p.6">If this header is used in a response with the application/octet-stream content-type, the implied suggestion is that the user |
|---|
| 1604 | agent should not display the response, but directly enter a `save response as...' dialog. |
|---|
| 1605 | </p> |
|---|
| 1606 | <p id="rfc.section.B.1.p.7">See <a href="#content-disposition.issues" title="Content-Disposition Issues">Section 8.2</a> for Content-Disposition security issues. |
|---|
| 1607 | </p> |
|---|
| 1608 | <h1 id="rfc.section.C"><a href="#rfc.section.C">C.</a> <a id="compatibility" href="#compatibility">Compatibility with Previous Versions</a></h1> |
|---|
| 1609 | <h2 id="rfc.section.C.1"><a href="#rfc.section.C.1">C.1</a> <a id="changes.from.rfc.2068" href="#changes.from.rfc.2068">Changes from RFC 2068</a></h2> |
|---|
| 1610 | <p id="rfc.section.C.1.p.1">Transfer-coding and message lengths all interact in ways that required fixing exactly when chunked encoding is used (to allow |
|---|
| 1611 | for transfer encoding that may not be self delimiting); it was important to straighten out exactly how message lengths are |
|---|
| 1612 | computed. (<a href="#entity.length" title="Entity Length">Section 4.2.2</a>, see also <a href="#Part1" id="rfc.xref.Part1.16"><cite title="HTTP/1.1, part 1: URIs, Connections, and Message Parsing">[Part1]</cite></a>, <a href="#Part5" id="rfc.xref.Part5.4"><cite title="HTTP/1.1, part 5: Range Requests and Partial Responses">[Part5]</cite></a> and <a href="#Part6" id="rfc.xref.Part6.5"><cite title="HTTP/1.1, part 6: Caching">[Part6]</cite></a>). |
|---|
| 1613 | </p> |
|---|
| 1614 | <p id="rfc.section.C.1.p.2">Charset wildcarding is introduced to avoid explosion of character set names in accept headers. (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.3" title="Accept-Charset">Section 6.2</a>) |
|---|
| 1615 | </p> |
|---|
| 1616 | <p id="rfc.section.C.1.p.3">Content-Base was deleted from the specification: it was not implemented widely, and there is no simple, safe way to introduce |
|---|
| 1617 | it without a robust extension mechanism. In addition, it is used in a similar, but not identical fashion in MHTML <a href="#RFC2557" id="rfc.xref.RFC2557.2"><cite title="MIME Encapsulation of Aggregate Documents, such as HTML (MHTML)">[RFC2557]</cite></a>. |
|---|
| 1618 | </p> |
|---|
| 1619 | <p id="rfc.section.C.1.p.4">A content-coding of "identity" was introduced, to solve problems discovered in caching. (<a href="#content.codings" title="Content Codings">Section 3.2</a>) |
|---|
| 1620 | </p> |
|---|
| 1621 | <p id="rfc.section.C.1.p.5">Quality Values of zero should indicate that "I don't want something" to allow clients to refuse a representation. (<a href="#quality.values" title="Quality Values">Section 3.4</a>) |
|---|
| 1622 | </p> |
|---|
| 1623 | <p id="rfc.section.C.1.p.6">The Alternates<span id="rfc.iref.a.5"></span><span id="rfc.iref.h.11"></span>, Content-Version<span id="rfc.iref.c.8"></span><span id="rfc.iref.h.12"></span>, Derived-From<span id="rfc.iref.d.2"></span><span id="rfc.iref.h.13"></span>, Link<span id="rfc.iref.l.1"></span><span id="rfc.iref.h.14"></span>, URI<span id="rfc.iref.u.1"></span><span id="rfc.iref.h.15"></span>, Public<span id="rfc.iref.p.1"></span><span id="rfc.iref.h.16"></span> and Content-Base<span id="rfc.iref.c.9"></span><span id="rfc.iref.h.17"></span> header fields were defined in previous versions of this specification, but not commonly implemented. See <a href="http://tools.ietf.org/html/rfc2068#section-19.6.2">Section 19.6.2</a> of <a href="#RFC2068" id="rfc.xref.RFC2068.5"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2068]</cite></a>. |
|---|
| 1624 | </p> |
|---|
| 1625 | <h2 id="rfc.section.C.2"><a href="#rfc.section.C.2">C.2</a> <a id="changes.from.rfc.2616" href="#changes.from.rfc.2616">Changes from RFC 2616</a></h2> |
|---|
| 1626 | <p id="rfc.section.C.2.p.1">Clarify contexts that charset is used in. (<a href="#character.sets" title="Character Sets">Section 3.1</a>) |
|---|
| 1627 | </p> |
|---|
| 1628 | <p id="rfc.section.C.2.p.2">Remove reference to non-existant identity transfer-coding value tokens. (<a href="#no.content-transfer-encoding" title="No Content-Transfer-Encoding">Appendix A.4</a>) |
|---|
| 1629 | </p> |
|---|
| 1630 | <h1 id="rfc.section.D"><a href="#rfc.section.D">D.</a> <a id="change.log" href="#change.log">Change Log (to be removed by RFC Editor before publication)</a></h1> |
|---|
| 1631 | <h2 id="rfc.section.D.1"><a href="#rfc.section.D.1">D.1</a> Since RFC2616 |
|---|
| 1632 | </h2> |
|---|
| 1633 | <p id="rfc.section.D.1.p.1">Extracted relevant partitions from <a href="#RFC2616" id="rfc.xref.RFC2616.2"><cite title="Hypertext Transfer Protocol -- HTTP/1.1">[RFC2616]</cite></a>. |
|---|
| 1634 | </p> |
|---|
| 1635 | <h2 id="rfc.section.D.2"><a href="#rfc.section.D.2">D.2</a> Since draft-ietf-httpbis-p3-payload-00 |
|---|
| 1636 | </h2> |
|---|
| 1637 | <p id="rfc.section.D.2.p.1">Closed issues: </p> |
|---|
| 1638 | <ul> |
|---|
| 1639 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/8">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/8</a>>: "Media Type Registrations" (<<a href="http://purl.org/NET/http-errata#media-reg">http://purl.org/NET/http-errata#media-reg</a>>) |
|---|
| 1640 | </li> |
|---|
| 1641 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/14">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/14</a>>: "Clarification regarding quoting of charset values" (<<a href="http://purl.org/NET/http-errata#charactersets">http://purl.org/NET/http-errata#charactersets</a>>) |
|---|
| 1642 | </li> |
|---|
| 1643 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/16">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/16</a>>: "Remove 'identity' token references" (<<a href="http://purl.org/NET/http-errata#identity">http://purl.org/NET/http-errata#identity</a>>) |
|---|
| 1644 | </li> |
|---|
| 1645 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/25">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/25</a>>: "Accept-Encoding BNF" |
|---|
| 1646 | </li> |
|---|
| 1647 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/35">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/35</a>>: "Normative and Informative references" |
|---|
| 1648 | </li> |
|---|
| 1649 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/46">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/46</a>>: "RFC1700 references" |
|---|
| 1650 | </li> |
|---|
| 1651 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/55">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/55</a>>: "Updating to RFC4288" |
|---|
| 1652 | </li> |
|---|
| 1653 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/65">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/65</a>>: "Informative references" |
|---|
| 1654 | </li> |
|---|
| 1655 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/66">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/66</a>>: "ISO-8859-1 Reference" |
|---|
| 1656 | </li> |
|---|
| 1657 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/68">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/68</a>>: "Encoding References Normative" |
|---|
| 1658 | </li> |
|---|
| 1659 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/86">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/86</a>>: "Normative up-to-date references" |
|---|
| 1660 | </li> |
|---|
| 1661 | </ul> |
|---|
| 1662 | <h2 id="rfc.section.D.3"><a href="#rfc.section.D.3">D.3</a> Since draft-ietf-httpbis-p3-payload-01 |
|---|
| 1663 | </h2> |
|---|
| 1664 | <p id="rfc.section.D.3.p.1">Ongoing work on ABNF conversion (<<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/36">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/36</a>>): |
|---|
| 1665 | </p> |
|---|
| 1666 | <ul> |
|---|
| 1667 | <li>Add explicit references to BNF syntax and rules imported from other parts of the specification.</li> |
|---|
| 1668 | </ul> |
|---|
| 1669 | <h2 id="rfc.section.D.4"><a href="#rfc.section.D.4">D.4</a> <a id="changes.since.02" href="#changes.since.02">Since draft-ietf-httpbis-p3-payload-02</a></h2> |
|---|
| 1670 | <p id="rfc.section.D.4.p.1">Closed issues: </p> |
|---|
| 1671 | <ul> |
|---|
| 1672 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/67">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/67</a>>: "Quoting Charsets" |
|---|
| 1673 | </li> |
|---|
| 1674 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/105">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/105</a>>: "Classification for Allow header" |
|---|
| 1675 | </li> |
|---|
| 1676 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/115">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/115</a>>: "missing default for qvalue in description of Accept-Encoding" |
|---|
| 1677 | </li> |
|---|
| 1678 | </ul> |
|---|
| 1679 | <p id="rfc.section.D.4.p.2">Ongoing work on IANA Message Header Registration (<<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/40">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/40</a>>): |
|---|
| 1680 | </p> |
|---|
| 1681 | <ul> |
|---|
| 1682 | <li>Reference RFC 3984, and update header registrations for headers defined in this document.</li> |
|---|
| 1683 | </ul> |
|---|
| 1684 | <h2 id="rfc.section.D.5"><a href="#rfc.section.D.5">D.5</a> <a id="changes.since.03" href="#changes.since.03">Since draft-ietf-httpbis-p3-payload-03</a></h2> |
|---|
| 1685 | <p id="rfc.section.D.5.p.1">Closed issues: </p> |
|---|
| 1686 | <ul> |
|---|
| 1687 | <li> <<a href="http://www3.tools.ietf.org/wg/httpbis/trac/ticket/121">http://www3.tools.ietf.org/wg/httpbis/trac/ticket/121</a>>: "RFC 1806 has been replaced by RFC2183" |
|---|
| 1688 | </li> |
|---|
| 1689 | </ul> |
|---|
| 1690 | <h1><a id="rfc.copyright" href="#rfc.copyright">Full Copyright Statement</a></h1> |
|---|
| 1691 | <p>This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the |
|---|
| 1692 | authors retain all their rights. |
|---|
| 1693 | </p> |
|---|
| 1694 | <p>This document and the information contained herein are provided on an “AS IS” basis and THE CONTRIBUTOR, THE ORGANIZATION |
|---|
| 1695 | HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE |
|---|
| 1696 | DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN |
|---|
| 1697 | WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. |
|---|
| 1698 | </p> |
|---|
| 1699 | <h1><a id="rfc.ipr" href="#rfc.ipr">Intellectual Property</a></h1> |
|---|
| 1700 | <p>The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might |
|---|
| 1701 | be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any |
|---|
| 1702 | license under such rights might or might not be available; nor does it represent that it has made any independent effort to |
|---|
| 1703 | identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and |
|---|
| 1704 | BCP 79. |
|---|
| 1705 | </p> |
|---|
| 1706 | <p>Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result |
|---|
| 1707 | of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users |
|---|
| 1708 | of this specification can be obtained from the IETF on-line IPR repository at <<a href="http://www.ietf.org/ipr">http://www.ietf.org/ipr</a>>. |
|---|
| 1709 | </p> |
|---|
| 1710 | <p>The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary |
|---|
| 1711 | rights that may cover technology that may be required to implement this standard. Please address the information to the IETF |
|---|
| 1712 | at <a href="mailto:ietf-ipr@ietf.org">ietf-ipr@ietf.org</a>. |
|---|
| 1713 | </p> |
|---|
| 1714 | <h1 id="rfc.index"><a href="#rfc.index">Index</a></h1> |
|---|
| 1715 | <p class="noprint"><a href="#rfc.index.A">A</a> <a href="#rfc.index.C">C</a> <a href="#rfc.index.D">D</a> <a href="#rfc.index.G">G</a> <a href="#rfc.index.H">H</a> <a href="#rfc.index.I">I</a> <a href="#rfc.index.L">L</a> <a href="#rfc.index.P">P</a> <a href="#rfc.index.R">R</a> <a href="#rfc.index.U">U</a> |
|---|
| 1716 | </p> |
|---|
| 1717 | <div class="print2col"> |
|---|
| 1718 | <ul class="ind"> |
|---|
| 1719 | <li class="indline0"><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul class="ind"> |
|---|
| 1720 | <li class="indline1">Accept header <a class="iref" href="#rfc.xref.header.accept.1">3.3</a>, <a class="iref" href="#rfc.xref.header.accept.2">5.1</a>, <a class="iref" href="#rfc.iref.a.1"><b>6.1</b></a>, <a class="iref" href="#rfc.xref.header.accept.3">7.1</a></li> |
|---|
| 1721 | <li class="indline1">Accept-Charset header <a class="iref" href="#rfc.xref.header.accept-charset.1">5.1</a>, <a class="iref" href="#rfc.iref.a.2"><b>6.2</b></a>, <a class="iref" href="#rfc.xref.header.accept-charset.2">7.1</a>, <a class="iref" href="#rfc.xref.header.accept-charset.3">C.1</a></li> |
|---|
| 1722 | <li class="indline1">Accept-Encoding header <a class="iref" href="#rfc.xref.header.accept-encoding.1">3.2</a>, <a class="iref" href="#rfc.xref.header.accept-encoding.2">5.1</a>, <a class="iref" href="#rfc.iref.a.3"><b>6.3</b></a>, <a class="iref" href="#rfc.xref.header.accept-encoding.3">7.1</a></li> |
|---|
| 1723 | <li class="indline1">Accept-Language header <a class="iref" href="#rfc.xref.header.accept-language.1">5.1</a>, <a class="iref" href="#rfc.iref.a.4"><b>6.4</b></a>, <a class="iref" href="#rfc.xref.header.accept-language.2">7.1</a></li> |
|---|
| 1724 | <li class="indline1">Alternates header <a class="iref" href="#rfc.iref.a.5"><b>C.1</b></a></li> |
|---|
| 1725 | </ul> |
|---|
| 1726 | </li> |
|---|
| 1727 | <li class="indline0"><a id="rfc.index.C" href="#rfc.index.C"><b>C</b></a><ul class="ind"> |
|---|
| 1728 | <li class="indline1">compress <a class="iref" href="#rfc.iref.c.1">3.2</a></li> |
|---|
| 1729 | <li class="indline1">Content-Base header <a class="iref" href="#rfc.iref.c.9"><b>C.1</b></a></li> |
|---|
| 1730 | <li class="indline1">Content-Disposition header <a class="iref" href="#rfc.xref.content-disposition.1">7.1</a>, <a class="iref" href="#rfc.xref.content-disposition.2">8.2</a>, <a class="iref" href="#rfc.iref.c.7"><b>B.1</b></a>, <a class="iref" href="#rfc.extref.c.22">B.1</a></li> |
|---|
| 1731 | <li class="indline1">Content-Encoding header <a class="iref" href="#rfc.xref.header.content-encoding.1">3.2</a>, <a class="iref" href="#rfc.xref.header.content-encoding.2">4.1</a>, <a class="iref" href="#rfc.iref.c.2"><b>6.5</b></a>, <a class="iref" href="#rfc.xref.header.content-encoding.3">6.5</a>, <a class="iref" href="#rfc.xref.header.content-encoding.4">7.1</a></li> |
|---|
| 1732 | <li class="indline1">Content-Language header <a class="iref" href="#rfc.xref.header.content-language.1">4.1</a>, <a class="iref" href="#rfc.iref.c.3"><b>6.6</b></a>, <a class="iref" href="#rfc.xref.header.content-language.2">7.1</a></li> |
|---|
| 1733 | <li class="indline1">Content-Location header <a class="iref" href="#rfc.xref.header.content-location.1">4.1</a>, <a class="iref" href="#rfc.iref.c.4"><b>6.7</b></a>, <a class="iref" href="#rfc.xref.header.content-location.2">7.1</a></li> |
|---|
| 1734 | <li class="indline1">Content-MD5 header <a class="iref" href="#rfc.xref.header.content-md5.1">4.1</a>, <a class="iref" href="#rfc.iref.c.5"><b>6.8</b></a>, <a class="iref" href="#rfc.xref.header.content-md5.2">7.1</a></li> |
|---|
| 1735 | <li class="indline1">Content-Type header <a class="iref" href="#rfc.xref.header.content-type.1">3.3</a>, <a class="iref" href="#rfc.xref.header.content-type.2">4.1</a>, <a class="iref" href="#rfc.iref.c.6"><b>6.9</b></a>, <a class="iref" href="#rfc.xref.header.content-type.3">7.1</a></li> |
|---|
| 1736 | <li class="indline1">Content-Version header <a class="iref" href="#rfc.iref.c.8"><b>C.1</b></a></li> |
|---|
| 1737 | </ul> |
|---|
| 1738 | </li> |
|---|
| 1739 | <li class="indline0"><a id="rfc.index.D" href="#rfc.index.D"><b>D</b></a><ul class="ind"> |
|---|
| 1740 | <li class="indline1">deflate <a class="iref" href="#rfc.iref.d.1">3.2</a></li> |
|---|
| 1741 | <li class="indline1">Derived-From header <a class="iref" href="#rfc.iref.d.2"><b>C.1</b></a></li> |
|---|
| 1742 | </ul> |
|---|
| 1743 | </li> |
|---|
| 1744 | <li class="indline0"><a id="rfc.index.G" href="#rfc.index.G"><b>G</b></a><ul class="ind"> |
|---|
| 1745 | <li class="indline1"><tt>Grammar</tt> |
|---|
| 1746 | <ul class="ind"> |
|---|
| 1747 | <li class="indline1"><tt>Accept</tt> <a class="iref" href="#rfc.iref.g.17"><b>6.1</b></a></li> |
|---|
| 1748 | <li class="indline1"><tt>Accept-Charset</tt> <a class="iref" href="#rfc.iref.g.21"><b>6.2</b></a></li> |
|---|
| 1749 | <li class="indline1"><tt>Accept-Encoding</tt> <a class="iref" href="#rfc.iref.g.22"><b>6.3</b></a></li> |
|---|
| 1750 | <li class="indline1"><tt>accept-extension</tt> <a class="iref" href="#rfc.iref.g.20"><b>6.1</b></a></li> |
|---|
| 1751 | <li class="indline1"><tt>Accept-Language</tt> <a class="iref" href="#rfc.iref.g.24"><b>6.4</b></a></li> |
|---|
| 1752 | <li class="indline1"><tt>accept-params</tt> <a class="iref" href="#rfc.iref.g.19"><b>6.1</b></a></li> |
|---|
| 1753 | <li class="indline1"><tt>attribute</tt> <a class="iref" href="#rfc.iref.g.8"><b>3.3</b></a></li> |
|---|
| 1754 | <li class="indline1"><tt>charset</tt> <a class="iref" href="#rfc.iref.g.1"><b>3.1</b></a></li> |
|---|
| 1755 | <li class="indline1"><tt>codings</tt> <a class="iref" href="#rfc.iref.g.23"><b>6.3</b></a></li> |
|---|
| 1756 | <li class="indline1"><tt>content-coding</tt> <a class="iref" href="#rfc.iref.g.2"><b>3.2</b></a></li> |
|---|
| 1757 | <li class="indline1"><tt>content-disposition</tt> <a class="iref" href="#rfc.iref.g.33"><b>B.1</b></a></li> |
|---|
| 1758 | <li class="indline1"><tt>Content-Encoding</tt> <a class="iref" href="#rfc.iref.g.26"><b>6.5</b></a></li> |
|---|
| 1759 | <li class="indline1"><tt>Content-Language</tt> <a class="iref" href="#rfc.iref.g.27"><b>6.6</b></a></li> |
|---|
| 1760 | <li class="indline1"><tt>Content-Location</tt> <a class="iref" href="#rfc.iref.g.28"><b>6.7</b></a></li> |
|---|
| 1761 | <li class="indline1"><tt>Content-MD5</tt> <a class="iref" href="#rfc.iref.g.29"><b>6.8</b></a></li> |
|---|
| 1762 | <li class="indline1"><tt>Content-Type</tt> <a class="iref" href="#rfc.iref.g.31"><b>6.9</b></a></li> |
|---|
| 1763 | <li class="indline1"><tt>disp-extension-parm</tt> <a class="iref" href="#rfc.iref.g.38"><b>B.1</b></a></li> |
|---|
| 1764 | <li class="indline1"><tt>disp-extension-token</tt> <a class="iref" href="#rfc.iref.g.37"><b>B.1</b></a></li> |
|---|
| 1765 | <li class="indline1"><tt>disposition-parm</tt> <a class="iref" href="#rfc.iref.g.35"><b>B.1</b></a></li> |
|---|
| 1766 | <li class="indline1"><tt>disposition-type</tt> <a class="iref" href="#rfc.iref.g.34"><b>B.1</b></a></li> |
|---|
| 1767 | <li class="indline1"><tt>entity-body</tt> <a class="iref" href="#rfc.iref.g.16"><b>4.2</b></a></li> |
|---|
| 1768 | <li class="indline1"><tt>entity-header</tt> <a class="iref" href="#rfc.iref.g.14"><b>4.1</b></a></li> |
|---|
| 1769 | <li class="indline1"><tt>extension-header</tt> <a class="iref" href="#rfc.iref.g.15"><b>4.1</b></a></li> |
|---|
| 1770 | <li class="indline1"><tt>filename-parm</tt> <a class="iref" href="#rfc.iref.g.36"><b>B.1</b></a></li> |
|---|
| 1771 | <li class="indline1"><tt>language-range</tt> <a class="iref" href="#rfc.iref.g.25"><b>6.4</b></a></li> |
|---|
| 1772 | <li class="indline1"><tt>language-tag</tt> <a class="iref" href="#rfc.iref.g.11"><b>3.5</b></a></li> |
|---|
| 1773 | <li class="indline1"><tt>md5-digest</tt> <a class="iref" href="#rfc.iref.g.30"><b>6.8</b></a></li> |
|---|
| 1774 | <li class="indline1"><tt>media-range</tt> <a class="iref" href="#rfc.iref.g.18"><b>6.1</b></a></li> |
|---|
| 1775 | <li class="indline1"><tt>media-type</tt> <a class="iref" href="#rfc.iref.g.4"><b>3.3</b></a></li> |
|---|
| 1776 | <li class="indline1"><tt>MIME-Version</tt> <a class="iref" href="#rfc.iref.g.32"><b>A.1</b></a></li> |
|---|
| 1777 | <li class="indline1"><tt>parameter</tt> <a class="iref" href="#rfc.iref.g.7"><b>3.3</b></a></li> |
|---|
| 1778 | <li class="indline1"><tt>primary-tag</tt> <a class="iref" href="#rfc.iref.g.12"><b>3.5</b></a></li> |
|---|
| 1779 | <li class="indline1"><tt>qvalue</tt> <a class="iref" href="#rfc.iref.g.10"><b>3.4</b></a></li> |
|---|
| 1780 | <li class="indline1"><tt>subtag</tt> <a class="iref" href="#rfc.iref.g.13"><b>3.5</b></a></li> |
|---|
| 1781 | <li class="indline1"><tt>subtype</tt> <a class="iref" href="#rfc.iref.g.6"><b>3.3</b></a></li> |
|---|
| 1782 | <li class="indline1"><tt>type</tt> <a class="iref" href="#rfc.iref.g.5"><b>3.3</b></a></li> |
|---|
| 1783 | <li class="indline1"><tt>value</tt> <a class="iref" href="#rfc.iref.g.9"><b>3.3</b></a></li> |
|---|
| 1784 | </ul> |
|---|
| 1785 | </li> |
|---|
| 1786 | <li class="indline1">gzip <a class="iref" href="#rfc.iref.g.3">3.2</a></li> |
|---|
| 1787 | </ul> |
|---|
| 1788 | </li> |
|---|
| 1789 | <li class="indline0"><a id="rfc.index.H" href="#rfc.index.H"><b>H</b></a><ul class="ind"> |
|---|
| 1790 | <li class="indline1">Headers |
|---|
| 1791 | <ul class="ind"> |
|---|
| 1792 | <li class="indline1">Accept <a class="iref" href="#rfc.xref.header.accept.1">3.3</a>, <a class="iref" href="#rfc.xref.header.accept.2">5.1</a>, <a class="iref" href="#rfc.iref.h.1"><b>6.1</b></a>, <a class="iref" href="#rfc.xref.header.accept.3">7.1</a></li> |
|---|
| 1793 | <li class="indline1">Accept-Charset <a class="iref" href="#rfc.xref.header.accept-charset.1">5.1</a>, <a class="iref" href="#rfc.iref.h.2"><b>6.2</b></a>, <a class="iref" href="#rfc.xref.header.accept-charset.2">7.1</a>, <a class="iref" href="#rfc.xref.header.accept-charset.3">C.1</a></li> |
|---|
| 1794 | <li class="indline1">Accept-Encoding <a class="iref" href="#rfc.xref.header.accept-encoding.1">3.2</a>, <a class="iref" href="#rfc.xref.header.accept-encoding.2">5.1</a>, <a class="iref" href="#rfc.iref.h.3"><b>6.3</b></a>, <a class="iref" href="#rfc.xref.header.accept-encoding.3">7.1</a></li> |
|---|
| 1795 | <li class="indline1">Accept-Language <a class="iref" href="#rfc.xref.header.accept-language.1">5.1</a>, <a class="iref" href="#rfc.iref.h.4"><b>6.4</b></a>, <a class="iref" href="#rfc.xref.header.accept-language.2">7.1</a></li> |
|---|
| 1796 | <li class="indline1">Alternate <a class="iref" href="#rfc.iref.h.11"><b>C.1</b></a></li> |
|---|
| 1797 | <li class="indline1">Content-Base <a class="iref" href="#rfc.iref.h.17"><b>C.1</b></a></li> |
|---|
| 1798 | <li class="indline1">Content-Disposition <a class="iref" href="#rfc.xref.content-disposition.1">7.1</a>, <a class="iref" href="#rfc.xref.content-disposition.2">8.2</a>, <a class="iref" href="#rfc.iref.h.10"><b>B.1</b></a>, <a class="iref" href="#rfc.extref.c.22">B.1</a></li> |
|---|
| 1799 | <li class="indline1">Content-Encoding <a class="iref" href="#rfc.xref.header.content-encoding.1">3.2</a>, <a class="iref" href="#rfc.xref.header.content-encoding.2">4.1</a>, <a class="iref" href="#rfc.iref.h.5"><b>6.5</b></a>, <a class="iref" href="#rfc.xref.header.content-encoding.3">6.5</a>, <a class="iref" href="#rfc.xref.header.content-encoding.4">7.1</a></li> |
|---|
| 1800 | <li class="indline1">Content-Language <a class="iref" href="#rfc.xref.header.content-language.1">4.1</a>, <a class="iref" href="#rfc.iref.h.6"><b>6.6</b></a>, <a class="iref" href="#rfc.xref.header.content-language.2">7.1</a></li> |
|---|
| 1801 | <li class="indline1">Content-Location <a class="iref" href="#rfc.xref.header.content-location.1">4.1</a>, <a class="iref" href="#rfc.iref.h.7"><b>6.7</b></a>, <a class="iref" href="#rfc.xref.header.content-location.2">7.1</a></li> |
|---|
| 1802 | <li class="indline1">Content-MD5 <a class="iref" href="#rfc.xref.header.content-md5.1">4.1</a>, <a class="iref" href="#rfc.iref.h.8"><b>6.8</b></a>, <a class="iref" href="#rfc.xref.header.content-md5.2">7.1</a></li> |
|---|
| 1803 | <li class="indline1">Content-Type <a class="iref" href="#rfc.xref.header.content-type.1">3.3</a>, <a class="iref" href="#rfc.xref.header.content-type.2">4.1</a>, <a class="iref" href="#rfc.iref.h.9"><b>6.9</b></a>, <a class="iref" href="#rfc.xref.header.content-type.3">7.1</a></li> |
|---|
| 1804 | <li class="indline1">Content-Version <a class="iref" href="#rfc.iref.h.12"><b>C.1</b></a></li> |
|---|
| 1805 | <li class="indline1">Derived-From <a class="iref" href="#rfc.iref.h.13"><b>C.1</b></a></li> |
|---|
| 1806 | <li class="indline1">Link <a class="iref" href="#rfc.iref.h.14"><b>C.1</b></a></li> |
|---|
| 1807 | <li class="indline1">Public <a class="iref" href="#rfc.iref.h.16"><b>C.1</b></a></li> |
|---|
| 1808 | <li class="indline1">URI <a class="iref" href="#rfc.iref.h.15"><b>C.1</b></a></li> |
|---|
| 1809 | </ul> |
|---|
| 1810 | </li> |
|---|
| 1811 | </ul> |
|---|
| 1812 | </li> |
|---|
| 1813 | <li class="indline0"><a id="rfc.index.I" href="#rfc.index.I"><b>I</b></a><ul class="ind"> |
|---|
| 1814 | <li class="indline1">identity <a class="iref" href="#rfc.iref.i.1">3.2</a></li> |
|---|
| 1815 | <li class="indline1"><em>ISO-8859-1</em> <a class="iref" href="#rfc.xref.ISO-8859-1.1">3.1.1</a>, <a class="iref" href="#ISO-8859-1"><b>10.1</b></a></li> |
|---|
| 1816 | </ul> |
|---|
| 1817 | </li> |
|---|
| 1818 | <li class="indline0"><a id="rfc.index.L" href="#rfc.index.L"><b>L</b></a><ul class="ind"> |
|---|
| 1819 | <li class="indline1">Link header <a class="iref" href="#rfc.iref.l.1"><b>C.1</b></a></li> |
|---|
| 1820 | </ul> |
|---|
| 1821 | </li> |
|---|
| 1822 | <li class="indline0"><a id="rfc.index.P" href="#rfc.index.P"><b>P</b></a><ul class="ind"> |
|---|
| 1823 | <li class="indline1"><em>Part1</em> <a class="iref" href="#rfc.xref.Part1.1">2</a>, <a class="iref" href="#rfc.xref.Part1.2">2</a>, <a class="iref" href="#rfc.xref.Part1.3">2</a>, <a class="iref" href="#rfc.xref.Part1.4">2</a>, <a class="iref" href="#rfc.xref.Part1.5">2</a>, <a class="iref" href="#rfc.xref.Part1.6">2</a>, <a class="iref" href="#rfc.xref.Part1.7">2</a>, <a class="iref" href="#rfc.xref.Part1.8">2</a>, <a class="iref" href="#rfc.xref.Part1.9">2</a>, <a class="iref" href="#rfc.xref.Part1.10">2</a>, <a class="iref" href="#rfc.xref.Part1.11">2</a>, <a class="iref" href="#rfc.xref.Part1.12">4.1</a>, <a class="iref" href="#rfc.xref.Part1.13">4.2</a>, <a class="iref" href="#rfc.xref.Part1.14">4.2.2</a>, <a class="iref" href="#Part1"><b>10.1</b></a>, <a class="iref" href="#rfc.xref.Part1.15">A.5</a>, <a class="iref" href="#rfc.xref.Part1.16">C.1</a><ul class="ind"> |
|---|
| 1824 | <li class="indline1"><em>Section 2.1</em> <a class="iref" href="#rfc.xref.Part1.1">2</a></li> |
|---|
| 1825 | <li class="indline1"><em>Section 2.2</em> <a class="iref" href="#rfc.xref.Part1.2">2</a>, <a class="iref" href="#rfc.xref.Part1.3">2</a>, <a class="iref" href="#rfc.xref.Part1.4">2</a>, <a class="iref" href="#rfc.xref.Part1.5">2</a>, <a class="iref" href="#rfc.xref.Part1.6">2</a>, <a class="iref" href="#rfc.xref.Part1.7">2</a></li> |
|---|
| 1826 | <li class="indline1"><em>Section 3.2.1</em> <a class="iref" href="#rfc.xref.Part1.8">2</a>, <a class="iref" href="#rfc.xref.Part1.10">2</a></li> |
|---|
| 1827 | <li class="indline1"><em>Section 4.2</em> <a class="iref" href="#rfc.xref.Part1.11">2</a></li> |
|---|
| 1828 | <li class="indline1"><em>Section 4.3</em> <a class="iref" href="#rfc.xref.Part1.13">4.2</a></li> |
|---|
| 1829 | <li class="indline1"><em>Section 4.4</em> <a class="iref" href="#rfc.xref.Part1.14">4.2.2</a></li> |
|---|
| 1830 | <li class="indline1"><em>Section 8.2</em> <a class="iref" href="#rfc.xref.Part1.9">2</a>, <a class="iref" href="#rfc.xref.Part1.12">4.1</a></li> |
|---|
| 1831 | <li class="indline1"><em>Section 8.7</em> <a class="iref" href="#rfc.xref.Part1.15">A.5</a></li> |
|---|
| 1832 | </ul> |
|---|
| 1833 | </li> |
|---|
| 1834 | <li class="indline1"><em>Part2</em> <a class="iref" href="#rfc.xref.Part2.1">5.1</a>, <a class="iref" href="#Part2"><b>10.1</b></a><ul class="ind"> |
|---|
| 1835 | <li class="indline1"><em>Section 10.9</em> <a class="iref" href="#rfc.xref.Part2.1">5.1</a></li> |
|---|
| 1836 | </ul> |
|---|
| 1837 | </li> |
|---|
| 1838 | <li class="indline1"><em>Part4</em> <a class="iref" href="#rfc.xref.Part4.1">2</a>, <a class="iref" href="#rfc.xref.Part4.2">4.1</a>, <a class="iref" href="#Part4"><b>10.1</b></a><ul class="ind"> |
|---|
| 1839 | <li class="indline1"><em>Section 7.6</em> <a class="iref" href="#rfc.xref.Part4.1">2</a>, <a class="iref" href="#rfc.xref.Part4.2">4.1</a></li> |
|---|
| 1840 | </ul> |
|---|
| 1841 | </li> |
|---|
| 1842 | <li class="indline1"><em>Part5</em> <a class="iref" href="#rfc.xref.Part5.1">2</a>, <a class="iref" href="#rfc.xref.Part5.2">3.3.2</a>, <a class="iref" href="#rfc.xref.Part5.3">4.1</a>, <a class="iref" href="#Part5"><b>10.1</b></a>, <a class="iref" href="#rfc.xref.Part5.4">C.1</a><ul class="ind"> |
|---|
| 1843 | <li class="indline1"><em>Section 6.2</em> <a class="iref" href="#rfc.xref.Part5.1">2</a>, <a class="iref" href="#rfc.xref.Part5.3">4.1</a></li> |
|---|
| 1844 | <li class="indline1"><em>Appendix A</em> <a class="iref" href="#rfc.xref.Part5.2">3.3.2</a></li> |
|---|
| 1845 | </ul> |
|---|
| 1846 | </li> |
|---|
| 1847 | <li class="indline1"><em>Part6</em> <a class="iref" href="#rfc.xref.Part6.1">2</a>, <a class="iref" href="#rfc.xref.Part6.2">4.1</a>, <a class="iref" href="#rfc.xref.Part6.3">5.1</a>, <a class="iref" href="#rfc.xref.Part6.4">6.7</a>, <a class="iref" href="#Part6"><b>10.1</b></a>, <a class="iref" href="#rfc.xref.Part6.5">C.1</a><ul class="ind"> |
|---|
| 1848 | <li class="indline1"><em>Section 8</em> <a class="iref" href="#rfc.xref.Part6.4">6.7</a></li> |
|---|
| 1849 | <li class="indline1"><em>Section 16.3</em> <a class="iref" href="#rfc.xref.Part6.1">2</a>, <a class="iref" href="#rfc.xref.Part6.2">4.1</a></li> |
|---|
| 1850 | <li class="indline1"><em>Section 16.5</em> <a class="iref" href="#rfc.xref.Part6.3">5.1</a></li> |
|---|
| 1851 | </ul> |
|---|
| 1852 | </li> |
|---|
| 1853 | <li class="indline1">Public header <a class="iref" href="#rfc.iref.p.1"><b>C.1</b></a></li> |
|---|
| 1854 | </ul> |
|---|
| 1855 | </li> |
|---|
| 1856 | <li class="indline0"><a id="rfc.index.R" href="#rfc.index.R"><b>R</b></a><ul class="ind"> |
|---|
| 1857 | <li class="indline1"><em>RFC1766</em> <a class="iref" href="#rfc.xref.RFC1766.1">3.5</a>, <a class="iref" href="#RFC1766"><b>10.1</b></a></li> |
|---|
| 1858 | <li class="indline1"><em>RFC1864</em> <a class="iref" href="#rfc.xref.RFC1864.1">6.8</a>, <a class="iref" href="#rfc.xref.RFC1864.2">6.8</a>, <a class="iref" href="#RFC1864"><b>10.1</b></a></li> |
|---|
| 1859 | <li class="indline1"><em>RFC1945</em> <a class="iref" href="#RFC1945"><b>10.2</b></a>, <a class="iref" href="#rfc.xref.RFC1945.1">B</a></li> |
|---|
| 1860 | <li class="indline1"><em>RFC1950</em> <a class="iref" href="#rfc.xref.RFC1950.1">3.2</a>, <a class="iref" href="#RFC1950"><b>10.1</b></a></li> |
|---|
| 1861 | <li class="indline1"><em>RFC1951</em> <a class="iref" href="#rfc.xref.RFC1951.1">3.2</a>, <a class="iref" href="#RFC1951"><b>10.1</b></a></li> |
|---|
| 1862 | <li class="indline1"><em>RFC1952</em> <a class="iref" href="#rfc.xref.RFC1952.1">3.2</a>, <a class="iref" href="#RFC1952"><b>10.1</b></a></li> |
|---|
| 1863 | <li class="indline1"><em>RFC2045</em> <a class="iref" href="#RFC2045"><b>10.1</b></a>, <a class="iref" href="#rfc.xref.RFC2045.1">A</a>, <a class="iref" href="#rfc.xref.RFC2045.2">A.1</a>, <a class="iref" href="#rfc.xref.RFC2045.3">A.2</a></li> |
|---|
| 1864 | <li class="indline1"><em>RFC2046</em> <a class="iref" href="#rfc.xref.RFC2046.1">3.3</a>, <a class="iref" href="#rfc.xref.RFC2046.2">3.3.2</a>, <a class="iref" href="#RFC2046"><b>10.1</b></a>, <a class="iref" href="#rfc.xref.RFC2046.3">A.2</a><ul class="ind"> |
|---|
| 1865 | <li class="indline1"><em>Section 5.1.1</em> <a class="iref" href="#rfc.xref.RFC2046.2">3.3.2</a></li> |
|---|
| 1866 | </ul> |
|---|
| 1867 | </li> |
|---|
| 1868 | <li class="indline1"><em>RFC2049</em> <a class="iref" href="#RFC2049"><b>10.2</b></a>, <a class="iref" href="#rfc.xref.RFC2049.1">A.2</a><ul class="ind"> |
|---|
| 1869 | <li class="indline1"><em>Section 4</em> <a class="iref" href="#rfc.xref.RFC2049.1">A.2</a></li> |
|---|
| 1870 | </ul> |
|---|
| 1871 | </li> |
|---|
| 1872 | <li class="indline1"><em>RFC2068</em> <a class="iref" href="#rfc.xref.RFC2068.1">§</a>, <a class="iref" href="#rfc.xref.RFC2068.2">§</a>, <a class="iref" href="#rfc.xref.RFC2068.3">§</a>, <a class="iref" href="#RFC2068"><b>10.2</b></a>, <a class="iref" href="#rfc.xref.RFC2068.4">B</a>, <a class="iref" href="#rfc.xref.RFC2068.5">C.1</a><ul class="ind"> |
|---|
| 1873 | <li class="indline1"><em>Section 19.6.2</em> <a class="iref" href="#rfc.xref.RFC2068.5">C.1</a></li> |
|---|
| 1874 | </ul> |
|---|
| 1875 | </li> |
|---|
| 1876 | <li class="indline1"><em>RFC2076</em> <a class="iref" href="#RFC2076"><b>10.2</b></a>, <a class="iref" href="#rfc.xref.RFC2076.1">B</a></li> |
|---|
| 1877 | <li class="indline1"><em>RFC2119</em> <a class="iref" href="#rfc.xref.RFC2119.1">1.1</a>, <a class="iref" href="#RFC2119"><b>10.1</b></a></li> |
|---|
| 1878 | <li class="indline1"><em>RFC2183</em> <a class="iref" href="#rfc.xref.RFC2183.1">8.2</a>, <a class="iref" href="#rfc.xref.RFC2183.2">8.2</a>, <a class="iref" href="#RFC2183"><b>10.2</b></a>, <a class="iref" href="#rfc.xref.RFC2183.3">B.1</a><ul class="ind"> |
|---|
| 1879 | <li class="indline1"><em>Section 5</em> <a class="iref" href="#rfc.xref.RFC2183.2">8.2</a></li> |
|---|
| 1880 | </ul> |
|---|
| 1881 | </li> |
|---|
| 1882 | <li class="indline1"><em>RFC2277</em> <a class="iref" href="#rfc.xref.RFC2277.1">3.1</a>, <a class="iref" href="#RFC2277"><b>10.2</b></a></li> |
|---|
| 1883 | <li class="indline1"><em>RFC2388</em> <a class="iref" href="#rfc.xref.RFC2388.1">3.3.2</a>, <a class="iref" href="#RFC2388"><b>10.2</b></a></li> |
|---|
| 1884 | <li class="indline1"><em>RFC2557</em> <a class="iref" href="#RFC2557"><b>10.2</b></a>, <a class="iref" href="#rfc.xref.RFC2557.1">A.6</a>, <a class="iref" href="#rfc.xref.RFC2557.2">C.1</a></li> |
|---|
| 1885 | <li class="indline1"><em>RFC2616</em> <a class="iref" href="#rfc.xref.RFC2616.1">1</a>, <a class="iref" href="#RFC2616"><b>10.2</b></a>, <a class="iref" href="#rfc.xref.RFC2616.2">D.1</a></li> |
|---|
| 1886 | <li class="indline1"><em>RFC2822</em> <a class="iref" href="#RFC2822"><b>10.2</b></a>, <a class="iref" href="#rfc.xref.RFC2822.1">A</a></li> |
|---|
| 1887 | <li class="indline1"><em>RFC3629</em> <a class="iref" href="#rfc.xref.RFC3629.1">3.1</a>, <a class="iref" href="#RFC3629"><b>10.2</b></a></li> |
|---|
| 1888 | <li class="indline1"><em>RFC3864</em> <a class="iref" href="#rfc.xref.RFC3864.1">7.1</a>, <a class="iref" href="#RFC3864"><b>10.2</b></a></li> |
|---|
| 1889 | <li class="indline1"><em>RFC4288</em> <a class="iref" href="#rfc.xref.RFC4288.1">3.3</a>, <a class="iref" href="#RFC4288"><b>10.2</b></a></li> |
|---|
| 1890 | </ul> |
|---|
| 1891 | </li> |
|---|
| 1892 | <li class="indline0"><a id="rfc.index.U" href="#rfc.index.U"><b>U</b></a><ul class="ind"> |
|---|
| 1893 | <li class="indline1">URI header <a class="iref" href="#rfc.iref.u.1"><b>C.1</b></a></li> |
|---|
| 1894 | </ul> |
|---|
| 1895 | </li> |
|---|
| 1896 | </ul> |
|---|
| 1897 | </div> |
|---|
| 1898 | </body> |
|---|
| 1899 | </html> |
|---|
![(please configure the [header_logo] section in trac.ini)](https://www.ietf.org/images/ietflogotrans.gif)
