242 lines
15 KiB
HTML
242 lines
15 KiB
HTML
|
<?xml version="1.0" encoding="UTF-8"?>
|
||
|
|
<!DOCTYPE html
|
||
|
|
PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
|
||
|
|
<html lang="en-us" xml:lang="en-us">
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
|
||
|
|
<meta name="security" content="public" />
|
||
|
|
<meta name="Robots" content="index,follow" />
|
||
|
|
<meta http-equiv="PICS-Label" content='(PICS-1.1 "http://www.icra.org/ratingsv02.html" l gen true r (cz 1 lz 1 nz 1 oz 1 vz 1) "http://www.rsac.org/ratingsv01.html" l gen true r (n 0 s 0 v 0 l 0) "http://www.classify.org/safesurf/" l gen true r (SS~~000 1))' />
|
||
|
|
<meta name="DC.Type" content="topic" />
|
||
|
|
<meta name="DC.Title" content="Module mod_negotiation" />
|
||
|
|
<meta name="copyright" content="(C) Copyright IBM Corporation 2002,2006" />
|
||
|
|
<meta name="DC.Rights.Owner" content="(C) Copyright IBM Corporation 2002,2006" />
|
||
|
|
<meta name="DC.Format" content="XHTML" />
|
||
|
|
<meta name="DC.Identifier" content="rzaiemod_negotiation" />
|
||
|
|
<meta name="DC.Language" content="en-us" />
|
||
|
|
<!-- All rights reserved. Licensed Materials Property of IBM -->
|
||
|
|
<!-- US Government Users Restricted Rights -->
|
||
|
|
<!-- Use, duplication or disclosure restricted by -->
|
||
|
|
<!-- GSA ADP Schedule Contract with IBM Corp. -->
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ibmdita.css" />
|
||
|
|
<link rel="stylesheet" type="text/css" href="./ic.css" />
|
||
|
|
<title>Module mod_negotiation</title>
|
||
|
|
</head>
|
||
|
|
<body id="rzaiemod_negotiation"><a name="rzaiemod_negotiation"><!-- --></a>
|
||
|
|
<!-- Java sync-link --><script language="Javascript" src="../rzahg/synch.js" type="text/javascript"></script>
|
||
|
|
<!--Java sync-link--><h1 class="topictitle1">Module mod_negotiation</h1>
|
||
|
|
<div><div class="important"><span class="importanttitle">Important:</span> Information
|
||
|
|
for this topic supports the latest PTF levels for HTTP Server for i5/OS .
|
||
|
|
It is recommended that you install the latest PTFs to upgrade to the latest
|
||
|
|
level of the HTTP Server for i5/OS. Some of the topics documented here are
|
||
|
|
not available prior to this update. See <a href="http://www-03.ibm.com/servers/eserver/iseries/software/http/services/service.html" target="_blank">http://www.ibm.com/servers/eserver/iseries/software/http/services/service.htm</a> <img src="www.gif" alt="Link outside Information Center" /> for more information. </div>
|
||
|
|
<p><strong>Summary</strong></p>
|
||
|
|
<p>Content negotiation is the selection of the document that best matches
|
||
|
|
the clients capabilities from one of several available documents. There are
|
||
|
|
two implementations of content negotiation: </p>
|
||
|
|
<ul><li> A type-map (a file with the handler type-map) which explicitly lists
|
||
|
|
the files containing the variants.</li>
|
||
|
|
<li>A MultiViews search (enabled by the MultiViews <a href="rzaiemod_core.htm#options">Options</a>) where the server does an implicit filename pattern match
|
||
|
|
and makes a choice from the results. </li>
|
||
|
|
</ul>
|
||
|
|
<p>See <a href="rzaiecontent-negotiation.htm">Content negotiation for HTTP Server (powered by Apache)</a> for
|
||
|
|
more information.</p>
|
||
|
|
<p><strong>Type maps</strong></p>
|
||
|
|
<p>A type map has the same format as RFC822 mail headers. It contains document
|
||
|
|
descriptions separated by blank lines, with lines beginning with a pound sign
|
||
|
|
('#') are treated as comments. A document description consists of several
|
||
|
|
header records. Records may be continued on multiple lines if the continuation
|
||
|
|
lines start with spaces. The leading space will be deleted and the lines concatenated.
|
||
|
|
A header record consists of a keyword name, which always ends in a colon,
|
||
|
|
followed by a value. Whitespace is allowed between the header name and value,
|
||
|
|
and between the tokens of value. The headers allowed are: </p>
|
||
|
|
|
||
|
|
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="border" border="1" rules="all"><thead align="left"><tr><th valign="top" id="d0e50">Header</th>
|
||
|
|
<th valign="top" id="d0e52">Description</th>
|
||
|
|
</tr>
|
||
|
|
</thead>
|
||
|
|
<tbody><tr><td valign="top" headers="d0e50 ">Content-Encoding </td>
|
||
|
|
<td valign="top" headers="d0e52 ">The encoding of the file. The server only recognizes
|
||
|
|
encoding that is defined by an AddEncoding directive. This normally includes
|
||
|
|
the encoding x-compress for compress'ed files, and x-gzip for gzip'ed files.
|
||
|
|
The x- prefix is ignored for encoding comparisons. </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td valign="top" headers="d0e50 ">Content-Language </td>
|
||
|
|
<td valign="top" headers="d0e52 ">The language of the variant, as an Internet standard
|
||
|
|
language tag (RFC 1766). An example is en, meaning English. </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td valign="top" headers="d0e50 ">Content-Length </td>
|
||
|
|
<td valign="top" headers="d0e52 ">The length of the file, in bytes. If this header is
|
||
|
|
not present, then the actual length of the file is used. </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td valign="top" headers="d0e50 ">Content-Type </td>
|
||
|
|
<td valign="top" headers="d0e52 ">The MIME media type of the document, with optional parameters.
|
||
|
|
Parameters are separated from the media type and from one another by a semicolon,
|
||
|
|
with a syntax of name=value. Common parameters include: <dl><dt class="dlterm"><strong>Parameter One</strong>: <em>level </em></dt>
|
||
|
|
<dd><ul><li>The <em>level</em> parameter is an integer specifying the version of the
|
||
|
|
media type. For text/html, this defaults to '2', otherwise '0'. </li>
|
||
|
|
</ul>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
<dl><dt class="dlterm"><strong>Parameter Two</strong>: <em>qs</em></dt>
|
||
|
|
<dd><ul><li>The <em>qs</em> parameter is a floating-point number with a value in the
|
||
|
|
range of '0.0' to '1.0', indicating the relative quality of this variant compared
|
||
|
|
to the other available variants, independent of the client's capabilities.
|
||
|
|
For example, a '.jpeg' file is usually of higher source quality than an '.ascii'
|
||
|
|
file it is attempting to represent a photograph. However, if the resource
|
||
|
|
being represents is ASCII art, then an ASCII file would have a higher source
|
||
|
|
quality than a '.jpeg' file. All Qs values therefore specific to a given source.
|
||
|
|
For example: <pre>Content-Type: image/jpeg; Qs=0.8</pre>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
</td>
|
||
|
|
</tr>
|
||
|
|
<tr><td valign="top" headers="d0e50 ">URL </td>
|
||
|
|
<td valign="top" headers="d0e52 ">The path to the file containing this variant, relative
|
||
|
|
to the map file. </td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
</div>
|
||
|
|
<p><strong>MultiViews</strong></p>
|
||
|
|
<p>A MultiViews search is enabled by the MultiViews Option. If the server
|
||
|
|
receives a request for /some/dir/QIBM and /some/dir/QIBM does not exist, then
|
||
|
|
the server reads the directory looking for all files named QIBM.* , and effectively
|
||
|
|
makes up a type map which names all those files, assigning them the same media
|
||
|
|
types and content-encodings it would have if the client had asked for one
|
||
|
|
of them by name. It then chooses the best match to the client's requirements,
|
||
|
|
and returns that document. </p>
|
||
|
|
<p><strong>Directives</strong></p>
|
||
|
|
<ul><li><a href="#cachenegotiateddocs">CacheNegotiatedDocs</a></li>
|
||
|
|
<li><a href="#forcelanguagepriority">ForceLanguagePriority</a></li>
|
||
|
|
<li><a href="#languagepriority">LanguagePriority</a></li>
|
||
|
|
</ul>
|
||
|
|
</div>
|
||
|
|
<div class="hr" id="cachenegotiateddocs"><a name="cachenegotiateddocs"><!-- --></a><h2 class="topictitle2">CacheNegotiatedDocs</h2>
|
||
|
|
<div>
|
||
|
|
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="void" border="0" rules="none"><tbody><tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Module">Module</a></strong>: mod_negotiation </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Syntax">Syntax</a></strong>: CacheNegotiatedDocs <em>on | off </em></td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Default">Default</a></strong>: CacheNegotiatedDocs off </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Context">Context</a></strong>: <span id="cachenegotiateddocs__cachenegotiateddocs_context"><a name="cachenegotiateddocs__cachenegotiateddocs_context"><!-- --></a>server
|
||
|
|
config, virtual host</span></td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Override">Override</a></strong>: none </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Origin">Origin</a></strong>: <span id="cachenegotiateddocs__cachenegotiateddocs_origin"><a name="cachenegotiateddocs__cachenegotiateddocs_origin"><!-- --></a>Apache </span></td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Example">Example</a></strong>: CacheNegotiatedDocs on </td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
</div>
|
||
|
|
<p>The CacheNegotiatedDocs directive allows content-negotiated documents requested
|
||
|
|
using HTTP/1.0 to be cached by proxy servers. </p>
|
||
|
|
<dl class="block"><dt class="dlterm"><strong>Parameter</strong>: <em>on | off </em></dt>
|
||
|
|
<dd><ul><li>Setting this directive to <em>on</em> could mean that clients behind proxies
|
||
|
|
may retrieve versions of the documents that are not the best match for their
|
||
|
|
abilities. The purpose of this directive is to make cache more efficient.
|
||
|
|
This directive only applies to requests which come from HTTP/1.0 browsers.
|
||
|
|
HTTP/1.1 provides much better control over the caching of negotiated documents,
|
||
|
|
and this directive has no effect in responses to HTTP/1.1 requests. </li>
|
||
|
|
</ul>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div class="hr" id="forcelanguagepriority"><a name="forcelanguagepriority"><!-- --></a><h2 class="topictitle2">ForceLanguagePriority</h2>
|
||
|
|
<div>
|
||
|
|
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="void" border="0" rules="none"><tbody><tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Module">Module</a></strong>: mod_negotiation </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Syntax">Syntax</a></strong>: ForceLanguagePriority <em>None | Prefer |
|
||
|
|
Fallback [Prefer | Fallback]</em> </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Default">Default</a></strong>: ForceLanguagePriority None</td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Context">Context</a></strong>: <span id="forcelanguagepriority__forcelanguagepriority_context"><a name="forcelanguagepriority__forcelanguagepriority_context"><!-- --></a>server
|
||
|
|
config, virtual host, directory, .htaccess </span></td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Override">Override</a></strong>: FileInfo </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Origin">Origin</a></strong>: <span id="forcelanguagepriority__forcelanguagepriority_origin"><a name="forcelanguagepriority__forcelanguagepriority_origin"><!-- --></a>Apache</span></td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Example">Example</a></strong>: See below.</td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
</div>
|
||
|
|
<p>The ForceLanguagePriority directive uses the given LanguagePriority to
|
||
|
|
satisfy negotiation where the server could otherwise not return a single matching
|
||
|
|
document.</p>
|
||
|
|
<dl class="block"><dt class="dlterm"><strong>Parameter</strong>: <em>None | Prefer | Fallback </em></dt>
|
||
|
|
<dd><ul><li>The <em>Prefer</em> parameter uses LanguagePriority to serve one valid result,
|
||
|
|
rather than returning an HTTP result 300 (MULTIPLE CHOICES) when there are
|
||
|
|
several equally valid choices. If the directives below were given, and the
|
||
|
|
user's Accept-Language header assigned <em>en</em> and <em>de</em> each as quality
|
||
|
|
.500 (equally acceptable) then the first matching variant (<em>en</em>) will
|
||
|
|
be served. <pre>LanguagePriority en Fr de
|
||
|
|
ForceLanguagePriority Prefer</pre>
|
||
|
|
</li>
|
||
|
|
<li>The <em>Fallback</em> parameter uses LanguagePriority to serve a valid result,
|
||
|
|
rather than returning an HTTP result 406 (NOT ACCEPTABLE). If the directives
|
||
|
|
below were given, and the user's Accept-Language only permitted an <em>en</em> language
|
||
|
|
response, but such a variant isn't found, then the first variant from the
|
||
|
|
LanguagePriority list is served. <pre>LanguagePriority en Fr de
|
||
|
|
ForceLanguagePriority Fallback</pre>
|
||
|
|
</li>
|
||
|
|
</ul>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
<p>Both options, <em>Prefer</em> and <em>Fallback</em>, may be specified, so either
|
||
|
|
the first matching variant from LanguagePriority will be served if more that
|
||
|
|
one variant is acceptable, or the first available document will be served
|
||
|
|
if none of the variants match the client's acceptable list of languages. </p>
|
||
|
|
<div class="note"><span class="notetitle">Note:</span> When specifying both <em>Prefer</em> and <em>Fallback</em> options, the
|
||
|
|
behavior is the same regardless of the order in which they are specified.</div>
|
||
|
|
<p>See <a href="rzaiemod_mime.htm#defaultlanguage">DefaultLanguage</a>, <a href="rzaiemod_mime.htm#addlanguage">AddLanguage</a> and <a href="#languagepriority">LanguagePriority</a>for
|
||
|
|
more information.</p>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
<div class="hr" id="languagepriority"><a name="languagepriority"><!-- --></a><h2 class="topictitle2">LanguagePriority</h2>
|
||
|
|
<div>
|
||
|
|
<div class="tablenoborder"><table cellpadding="4" cellspacing="0" summary="" frame="void" border="0" rules="none"><tbody><tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Module">Module</a></strong>: mod_negotiation</td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Syntax">Syntax</a></strong>: LanguagePriority <em>MIME-lang [MIME-lang...]</em> </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Default">Default</a></strong>: none </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Context">Context</a></strong>: <span id="languagepriority__languagepriority_context"><a name="languagepriority__languagepriority_context"><!-- --></a>server
|
||
|
|
config, virtual host, directory, .htaccess</span></td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Override">Override</a></strong>: FileInfo </td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Origin">Origin</a></strong>: <span id="languagepriority__languagepriority_origin"><a name="languagepriority__languagepriority_origin"><!-- --></a>Apache </span></td>
|
||
|
|
</tr>
|
||
|
|
<tr><td colspan="2" valign="top"><strong><a href="rzaiedirective-dict.htm#rzaiedirective-dict__Example">Example</a></strong>: LanguagePriority en Fr de </td>
|
||
|
|
</tr>
|
||
|
|
</tbody>
|
||
|
|
</table>
|
||
|
|
</div>
|
||
|
|
<p>The LanguagePriority directive sets the precedence of language variants
|
||
|
|
for the case where the client does not express a preference when handling
|
||
|
|
a MultiViews request. The list of MIME-lang are in order of decreasing preference. </p>
|
||
|
|
<dl class="block"><dt class="dlterm"><strong>Parameter</strong>: <em>MIME-lang </em></dt>
|
||
|
|
<dd><ul><li>The <em>MIME-lang</em> parameter is any Internet standard language tag or
|
||
|
|
MIME language designation. </li>
|
||
|
|
</ul>
|
||
|
|
</dd>
|
||
|
|
</dl>
|
||
|
|
<p>This directive may be configured multiple times in a container. The directives
|
||
|
|
are processed from the first to the last occurrence. </p>
|
||
|
|
<div class="note"><span class="notetitle">Note:</span> This directive only has an effect if a best language cannot be determined
|
||
|
|
by any other means. If the client expresses a language preference, this directive
|
||
|
|
has no effect on the file selected during content negotiation. </div>
|
||
|
|
</div>
|
||
|
|
</div>
|
||
|
|
|
||
|
|
</body>
|
||
|
|
</html>
|