Changeset 2077


Ignore:
Timestamp:
Dec 31, 2012, 9:58:52 PM (7 years ago)
Author:
fielding@…
Message:

(editorial) another attempt to explain GMT as UTC

Location:
draft-ietf-httpbis/latest
Files:
2 edited

Legend:

Unmodified
Added
Removed
  • draft-ietf-httpbis/latest/p2-semantics.html

    r2076 r2077  
    28042804      <h3 id="rfc.section.7.1.1"><a href="#rfc.section.7.1.1">7.1.1</a>&nbsp;<a id="origination.date" href="#origination.date">Origination Date</a></h3>
    28052805      <h4 id="rfc.section.7.1.1.1"><a href="#rfc.section.7.1.1.1">7.1.1.1</a>&nbsp;<a id="http.date" href="#http.date">Date/Time Formats</a></h4>
    2806       <p id="rfc.section.7.1.1.1.p.1">HTTP applications have historically allowed three different formats for date/time stamps. However, the preferred format is
    2807          a fixed-length subset of that defined by <a href="#RFC1123" id="rfc.xref.RFC1123.1"><cite title="Requirements for Internet Hosts - Application and Support">[RFC1123]</cite></a>:
     2806      <p id="rfc.section.7.1.1.1.p.1">HTTP has historically allowed three different formats for date/time stamps. However, the preferred format is a fixed-length
     2807         subset of that defined by <a href="#RFC1123" id="rfc.xref.RFC1123.1"><cite title="Requirements for Internet Hosts - Application and Support">[RFC1123]</cite></a>:
    28082808      </p>
    28092809      <div id="rfc.figure.u.42"></div><pre class="text">Sun, 06 Nov 1994 08:49:37 GMT  ; RFC 1123
     
    28112811      <div id="rfc.figure.u.43"></div><pre class="text">Sunday, 06-Nov-94 08:49:37 GMT ; obsolete RFC 850 format
    28122812Sun Nov  6 08:49:37 1994       ; ANSI C's asctime() format
    2813 </pre><p id="rfc.section.7.1.1.1.p.5">HTTP/1.1 clients and servers that parse a date value <em class="bcp14">MUST</em> accept all three formats (for compatibility with HTTP/1.0), though they <em class="bcp14">MUST</em> only generate the RFC 1123 format for representing HTTP-date values in header fields.
    2814       </p>
    2815       <p id="rfc.section.7.1.1.1.p.6">All HTTP date/time stamps are represented in Greenwich Mean Time (GMT), without exception. For the purposes of HTTP, GMT is
    2816          exactly equal to UTC (Coordinated Universal Time). This is indicated in the first two formats by the inclusion of "GMT" as
    2817          the three-letter abbreviation for time zone, and is assumed when reading the asctime format. HTTP-date is case sensitive.
    2818          A sender <em class="bcp14">MUST NOT</em> generate additional whitespace in an HTTP-date beyond that specifically included as SP in the grammar.
     2813</pre><p id="rfc.section.7.1.1.1.p.5">HTTP always represents dates as an instance of Coordinated Universal Time (UTC), without exception; the first two formats
     2814         indicate UTC as "GMT" in the three-letter abbreviation for time zone. Recipients <em class="bcp14">MAY</em> assume UTC even if the time zone abbreviation is missing, invalid, or might indicate some other time zone.
    28192815      </p>
    28202816      <div id="rfc.figure.u.44"></div><pre class="inline"><span id="rfc.iref.g.39"></span>  <a href="#http.date" class="smpl">HTTP-date</a>    = <a href="#preferred.date.format" class="smpl">rfc1123-date</a> / <a href="#obsolete.date.formats" class="smpl">obs-date</a>
    28212817</pre><div id="preferred.date.format">
    2822          <p id="rfc.section.7.1.1.1.p.8">                    Preferred format:</p>
     2818         <p id="rfc.section.7.1.1.1.p.7">                    Preferred format:</p>
    28232819      </div>
    28242820      <div id="rfc.figure.u.45"></div><pre class="inline"><span id="rfc.iref.g.40"></span><span id="rfc.iref.g.41"></span><span id="rfc.iref.g.42"></span><span id="rfc.iref.g.43"></span><span id="rfc.iref.g.44"></span><span id="rfc.iref.g.45"></span><span id="rfc.iref.g.46"></span><span id="rfc.iref.g.47"></span><span id="rfc.iref.g.48"></span><span id="rfc.iref.g.49"></span><span id="rfc.iref.g.50"></span><span id="rfc.iref.g.51"></span>  <a href="#preferred.date.format" class="smpl">rfc1123-date</a> = <a href="#preferred.date.format" class="smpl">day-name</a> "," <a href="#imported.abnf" class="smpl">SP</a> date1 <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">time-of-day</a> <a href="#imported.abnf" class="smpl">SP</a> <a href="#preferred.date.format" class="smpl">GMT</a>
     
    28602856  <a href="#preferred.date.format" class="smpl">minute</a>       = 2<a href="#imported.abnf" class="smpl">DIGIT</a>               
    28612857  <a href="#preferred.date.format" class="smpl">second</a>       = 2<a href="#imported.abnf" class="smpl">DIGIT</a>               
    2862 </pre><p id="rfc.section.7.1.1.1.p.10">The semantics of <a href="#preferred.date.format" class="smpl">day-name</a>, <a href="#preferred.date.format" class="smpl">day</a>, <a href="#preferred.date.format" class="smpl">month</a>, <a href="#preferred.date.format" class="smpl">year</a>, and <a href="#preferred.date.format" class="smpl">time-of-day</a> are the same as those defined for the RFC 5322 constructs with the corresponding name (<a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="http://tools.ietf.org/html/rfc5322#section-3.3">Section 3.3</a>).
     2858</pre><p id="rfc.section.7.1.1.1.p.9">The semantics of <a href="#preferred.date.format" class="smpl">day-name</a>, <a href="#preferred.date.format" class="smpl">day</a>, <a href="#preferred.date.format" class="smpl">month</a>, <a href="#preferred.date.format" class="smpl">year</a>, and <a href="#preferred.date.format" class="smpl">time-of-day</a> are the same as those defined for the RFC 5322 constructs with the corresponding name (<a href="#RFC5322" id="rfc.xref.RFC5322.3"><cite title="Internet Message Format">[RFC5322]</cite></a>, <a href="http://tools.ietf.org/html/rfc5322#section-3.3">Section 3.3</a>).
    28632859      </p>
    28642860      <div id="obsolete.date.formats">
    2865          <p id="rfc.section.7.1.1.1.p.11">              Obsolete formats:</p>
     2861         <p id="rfc.section.7.1.1.1.p.10">              Obsolete formats:</p>
    28662862      </div>
    28672863      <div id="rfc.figure.u.46"></div><pre class="inline"><span id="rfc.iref.g.52"></span>  <a href="#obsolete.date.formats" class="smpl">obs-date</a>     = <a href="#obsolete.date.formats" class="smpl">rfc850-date</a> / <a href="#obsolete.date.formats" class="smpl">asctime-date</a>
     
    28802876  <a href="#obsolete.date.formats" class="smpl">date3</a>        = <a href="#preferred.date.format" class="smpl">month</a> <a href="#imported.abnf" class="smpl">SP</a> ( 2<a href="#imported.abnf" class="smpl">DIGIT</a> / ( <a href="#imported.abnf" class="smpl">SP</a> 1<a href="#imported.abnf" class="smpl">DIGIT</a> ))
    28812877                 ; month day (e.g., Jun  2)
    2882 </pre><div class="note" id="rfc.section.7.1.1.1.p.15">
     2878</pre><p id="rfc.section.7.1.1.1.p.14">HTTP-date is case sensitive. A sender <em class="bcp14">MUST NOT</em> generate additional whitespace in an HTTP-date beyond that specifically included as SP in the grammar.
     2879      </p>
     2880      <p id="rfc.section.7.1.1.1.p.15">Recipients that parse a date value <em class="bcp14">MUST</em> accept all three formats (for compatibility with HTTP/1.0). A sender <em class="bcp14">MUST</em> only generate the RFC 1123 format when sending HTTP-date values in header fields.
     2881      </p>
     2882      <div class="note" id="rfc.section.7.1.1.1.p.16">
    28832883         <p> <b>Note:</b> Recipients of date values are encouraged to be robust in accepting date values that might have been sent by non-HTTP applications,
    28842884            as is sometimes the case when retrieving or posting messages via proxies/gateways to SMTP or NNTP.
    28852885         </p>
    28862886      </div>
    2887       <div class="note" id="rfc.section.7.1.1.1.p.16">
     2887      <div class="note" id="rfc.section.7.1.1.1.p.17">
    28882888         <p> <b>Note:</b> HTTP requirements for the date/time stamp format apply only to their usage within the protocol stream. Clients and servers
    28892889            are not required to use these formats for user presentation, request logging, etc.
  • draft-ietf-httpbis/latest/p2-semantics.xml

    r2076 r2077  
    35123512  <x:anchor-alias value="HTTP-date"/>
    35133513<t>
    3514    HTTP applications have historically allowed three different formats
     3514   HTTP has historically allowed three different formats
    35153515   for date/time stamps. However, the preferred format is a fixed-length subset
    35163516   of that defined by <xref target="RFC1123"/>:
     
    35283528</artwork></figure>
    35293529<t>
    3530    HTTP/1.1 clients and servers that parse a date value &MUST; accept
    3531    all three formats (for compatibility with HTTP/1.0), though they &MUST;
    3532    only generate the RFC 1123 format for representing HTTP-date values
    3533    in header fields.
    3534 </t>
    3535 <t>
    3536    All HTTP date/time stamps are represented in Greenwich Mean Time
    3537    (GMT), without exception. For the purposes of HTTP, GMT is exactly
    3538    equal to UTC (Coordinated Universal Time). This is indicated in the
    3539    first two formats by the inclusion of "GMT" as the three-letter
    3540    abbreviation for time zone, and is assumed when reading the
    3541    asctime format. HTTP-date is case sensitive. A sender &MUST-NOT; generate
    3542    additional whitespace in an HTTP-date beyond that specifically included as
    3543    SP in the grammar.
     3530   HTTP always represents dates as an instance of Coordinated Universal Time
     3531   (UTC), without exception; the first two formats indicate UTC as "GMT" in
     3532   the three-letter abbreviation for time zone. Recipients &MAY; assume UTC
     3533   even if the time zone abbreviation is missing, invalid, or might indicate
     3534   some other time zone.
    35443535</t>
    35453536<figure><artwork type="abnf2616"><iref primary="true" item="Grammar" subitem="HTTP-date"/>
     
    36363627                 ; month day (e.g., Jun  2)
    36373628</artwork></figure>
     3629<t>
     3630   HTTP-date is case sensitive.
     3631   A sender &MUST-NOT; generate additional whitespace in an HTTP-date beyond
     3632   that specifically included as SP in the grammar.
     3633</t>
     3634<t>
     3635   Recipients that parse a date value &MUST; accept all three formats (for
     3636   compatibility with HTTP/1.0). A sender &MUST; only generate the RFC 1123
     3637   format when sending HTTP-date values in header fields.
     3638</t>
    36383639<x:note>
    36393640  <t>
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