Ignore:
Timestamp:
Mar 30, 2011, 7:03:49 AM (9 years ago)
Author:
julian.reschke@…
Message:

Remove ISO-8859-1 default for text/*, remove special-case for ISO-8859-1 from Accept-Charset (see #20)

File:
1 edited

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  • draft-ietf-httpbis/latest/p3-payload.html

    r1234 r1240  
    546546         </li>
    547547         <li>2.&nbsp;&nbsp;&nbsp;<a href="#protocol.parameters">Protocol Parameters</a><ul>
    548                <li>2.1&nbsp;&nbsp;&nbsp;<a href="#character.sets">Character Encodings (charset)</a><ul>
    549                      <li>2.1.1&nbsp;&nbsp;&nbsp;<a href="#missing.charset">Missing Charset</a></li>
    550                   </ul>
    551                </li>
     548               <li>2.1&nbsp;&nbsp;&nbsp;<a href="#character.sets">Character Encodings (charset)</a></li>
    552549               <li>2.2&nbsp;&nbsp;&nbsp;<a href="#content.codings">Content Codings</a><ul>
    553550                     <li>2.2.1&nbsp;&nbsp;&nbsp;<a href="#content.coding.registry">Content Coding Registry</a></li>
     
    703700      <p id="rfc.section.2.1.p.6">Implementors need to 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>.
    704701      </p>
    705       <h3 id="rfc.section.2.1.1"><a href="#rfc.section.2.1.1">2.1.1</a>&nbsp;<a id="missing.charset" href="#missing.charset">Missing Charset</a></h3>
    706       <p id="rfc.section.2.1.1.p.1">Some HTTP/1.0 software has interpreted a Content-Type header field without charset parameter incorrectly to mean "recipient
    707          should 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.
    708       </p>
    709       <p id="rfc.section.2.1.1.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
    710          displaying a document. See <a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Section&nbsp;2.3.1</a>.
    711       </p>
    712702      <h2 id="rfc.section.2.2"><a href="#rfc.section.2.2">2.2</a>&nbsp;<a id="content.codings" href="#content.codings">Content Codings</a></h2>
    713703      <p id="rfc.section.2.2.p.1">Content coding values indicate an encoding transformation that has been or can be applied to a representation. Content codings
     
    798788      <p id="rfc.section.2.3.1.p.3">If a representation is encoded with a content-coding, the underlying data <em class="bcp14">MUST</em> be in a form defined above prior to being encoded.
    799789      </p>
    800       <p id="rfc.section.2.3.1.p.4">The "charset" parameter is used with some media types to define the character encoding (<a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;2.1</a>) of the data. When no explicit charset parameter is provided by the sender, media subtypes of the "text" type are defined
    801          to have a default charset value of "ISO-8859-1" when received via HTTP. Data in character encodings other than "ISO-8859-1"
    802          or its subsets <em class="bcp14">MUST</em> be labeled with an appropriate charset value. See <a href="#missing.charset" title="Missing Charset">Section&nbsp;2.1.1</a> for compatibility problems.
    803       </p>
    804790      <h3 id="rfc.section.2.3.2"><a href="#rfc.section.2.3.2">2.3.2</a>&nbsp;<a id="multipart.types" href="#multipart.types">Multipart Types</a></h3>
    805791      <p id="rfc.section.2.3.2.p.1">MIME provides for a number of "multipart" types — encapsulations of one or more representations within a single message-body.
     
    11481134      </p>
    11491135      <div id="rfc.figure.u.16"></div><pre class="text">  Accept-Charset: iso-8859-5, unicode-1-1;q=0.8
    1150 </pre><p id="rfc.section.6.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character encoding (including ISO-8859-1) which
    1151          is not mentioned elsewhere in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then all character
    1152          encodings not explicitly mentioned get a quality value of 0, except for ISO-8859-1, which gets a quality value of 1 if not
    1153          explicitly mentioned.
     1136</pre><p id="rfc.section.6.2.p.5">The special value "*", if present in the Accept-Charset field, matches every character encoding which is not mentioned elsewhere
     1137         in the Accept-Charset field. If no "*" is present in an Accept-Charset field, then all character encodings not explicitly
     1138         mentioned get a quality value of 0.
    11541139      </p>
    11551140      <p id="rfc.section.6.2.p.6">If no Accept-Charset header field is present, the default is that any character encoding is acceptable. If an Accept-Charset
     
    15381523      <h2 id="rfc.references.1"><a href="#rfc.section.10.1" id="rfc.section.10.1">10.1</a> Normative References
    15391524      </h2>
    1540       <table>                               
    1541          <tr>
    1542             <td class="reference"><b id="ISO-8859-1">[ISO-8859-1]</b></td>
    1543             <td class="top">International Organization for Standardization, “Information technology -- 8-bit single-byte coded graphic character sets -- Part 1: Latin alphabet No. 1”, ISO/IEC&nbsp;8859-1:1998, 1998.</td>
    1544          </tr>
     1525      <table>                             
    15451526         <tr>
    15461527            <td class="reference"><b id="Part1">[Part1]</b></td>
     
    17871768      <p id="rfc.section.C.p.1">Clarify contexts that charset is used in. (<a href="#character.sets" title="Character Encodings (charset)">Section&nbsp;2.1</a>)
    17881769      </p>
    1789       <p id="rfc.section.C.p.2">Change ABNF productions for header fields to only define the field value. (<a href="#header.fields" title="Header Field Definitions">Section&nbsp;6</a>)
    1790       </p>
    1791       <p id="rfc.section.C.p.3">Remove base URI setting semantics for Content-Location due to poor implementation support, which was caused by too many broken
     1770      <p id="rfc.section.C.p.2">Remove the default character encoding for text media types; the default now is whatever the media type definition says. (<a href="#canonicalization.and.text.defaults" title="Canonicalization and Text Defaults">Section&nbsp;2.3.1</a>)
     1771      </p>
     1772      <p id="rfc.section.C.p.3">Change ABNF productions for header fields to only define the field value. (<a href="#header.fields" title="Header Field Definitions">Section&nbsp;6</a>)
     1773      </p>
     1774      <p id="rfc.section.C.p.4">Remove ISO-8859-1 special-casing in Accept-Charset. (<a href="#header.accept-charset" id="rfc.xref.header.accept-charset.3" title="Accept-Charset">Section&nbsp;6.2</a>)
     1775      </p>
     1776      <p id="rfc.section.C.p.5">Remove base URI setting semantics for Content-Location due to poor implementation support, which was caused by too many broken
    17921777         servers emitting bogus Content-Location header fields, and also the potentially undesirable effect of potentially breaking
    17931778         relative links in content-negotiated resources. (<a href="#header.content-location" id="rfc.xref.header.content-location.3" title="Content-Location">Section&nbsp;6.7</a>)
    17941779      </p>
    1795       <p id="rfc.section.C.p.4">Remove reference to non-existant identity transfer-coding value tokens. (<a href="#no.content-transfer-encoding" title="No Content-Transfer-Encoding">Appendix&nbsp;A.5</a>)
     1780      <p id="rfc.section.C.p.6">Remove reference to non-existant identity transfer-coding value tokens. (<a href="#no.content-transfer-encoding" title="No Content-Transfer-Encoding">Appendix&nbsp;A.5</a>)
    17961781      </p>
    17971782      <h1 id="rfc.section.D"><a href="#rfc.section.D">D.</a>&nbsp;<a id="collected.abnf" href="#collected.abnf">Collected ABNF</a></h1>
     
    20562041      <p id="rfc.section.E.15.p.1">Closed issues: </p>
    20572042      <ul>
     2043         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/20">http://tools.ietf.org/wg/httpbis/trac/ticket/20</a>&gt;: "Default charsets for text media types"
     2044         </li>
    20582045         <li> &lt;<a href="http://tools.ietf.org/wg/httpbis/trac/ticket/276">http://tools.ietf.org/wg/httpbis/trac/ticket/276</a>&gt;: "untangle ABNFs for header fields"
    20592046         </li>
     
    20662053            <li><a id="rfc.index.A" href="#rfc.index.A"><b>A</b></a><ul>
    20672054                  <li>Accept header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">2.3</a>, <a href="#rfc.xref.header.accept.2">5.1</a>, <a href="#rfc.iref.a.1"><b>6.1</b></a>, <a href="#rfc.xref.header.accept.3">7.1</a></li>
    2068                   <li>Accept-Charset header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">5.1</a>, <a href="#rfc.iref.a.2"><b>6.2</b></a>, <a href="#rfc.xref.header.accept-charset.2">7.1</a></li>
     2055                  <li>Accept-Charset header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">5.1</a>, <a href="#rfc.iref.a.2"><b>6.2</b></a>, <a href="#rfc.xref.header.accept-charset.2">7.1</a>, <a href="#rfc.xref.header.accept-charset.3">C</a></li>
    20692056                  <li>Accept-Encoding header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">2.2</a>, <a href="#rfc.xref.header.accept-encoding.2">5.1</a>, <a href="#rfc.iref.a.3"><b>6.3</b></a>, <a href="#rfc.xref.header.accept-encoding.3">7.1</a></li>
    20702057                  <li>Accept-Language header field&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">5.1</a>, <a href="#rfc.iref.a.4"><b>6.4</b></a>, <a href="#rfc.xref.header.accept-language.2">7.1</a></li>
     
    21332120                     <ul>
    21342121                        <li>Accept&nbsp;&nbsp;<a href="#rfc.xref.header.accept.1">2.3</a>, <a href="#rfc.xref.header.accept.2">5.1</a>, <a href="#rfc.iref.h.1"><b>6.1</b></a>, <a href="#rfc.xref.header.accept.3">7.1</a></li>
    2135                         <li>Accept-Charset&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">5.1</a>, <a href="#rfc.iref.h.2"><b>6.2</b></a>, <a href="#rfc.xref.header.accept-charset.2">7.1</a></li>
     2122                        <li>Accept-Charset&nbsp;&nbsp;<a href="#rfc.xref.header.accept-charset.1">5.1</a>, <a href="#rfc.iref.h.2"><b>6.2</b></a>, <a href="#rfc.xref.header.accept-charset.2">7.1</a>, <a href="#rfc.xref.header.accept-charset.3">C</a></li>
    21362123                        <li>Accept-Encoding&nbsp;&nbsp;<a href="#rfc.xref.header.accept-encoding.1">2.2</a>, <a href="#rfc.xref.header.accept-encoding.2">5.1</a>, <a href="#rfc.iref.h.3"><b>6.3</b></a>, <a href="#rfc.xref.header.accept-encoding.3">7.1</a></li>
    21372124                        <li>Accept-Language&nbsp;&nbsp;<a href="#rfc.xref.header.accept-language.1">5.1</a>, <a href="#rfc.iref.h.4"><b>6.4</b></a>, <a href="#rfc.xref.header.accept-language.2">7.1</a></li>
     
    21482135            <li><a id="rfc.index.I" href="#rfc.index.I"><b>I</b></a><ul>
    21492136                  <li>identity (Coding Format)&nbsp;&nbsp;<a href="#rfc.iref.i.1">2.2</a></li>
    2150                   <li><em>ISO-8859-1</em>&nbsp;&nbsp;<a href="#rfc.xref.ISO-8859-1.1">2.1.1</a>, <a href="#ISO-8859-1"><b>10.1</b></a></li>
    21512137               </ul>
    21522138            </li>
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