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cvs commit: httpd-2.0/docs/manual/mod mod_isapi.xml mod_mime_magic.xml mod_negotiation.xml
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Added: docs/manual/mod mod_isapi.xml mod_mime_magic.xml
mod_negotiation.xml
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1.1 httpd-2.0/docs/manual/mod/mod_isapi.xml
Index: mod_isapi.xml
===================================================================
<?xml version="1.0"?>
<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
<?xml-stylesheet type="text/xsl" href="../style/manual.xsl"?>
<modulesynopsis>
<name>mod_isapi</name>
<description>ISAPI Extensions within Apache for Windows</description>
<status>Base</status>
<sourcefile>mod_isapi.c</sourcefile>
<identifier>isapi_module</identifier>
<compatibility>Win32 only</compatibility>
<summary>
<p>This module implements the Internet Server extension API. It
allows Internet Server extensions (<em>e.g.</em> ISAPI .dll
modules) to be served by Apache for Windows, subject to the
noted restrictions.</p>
<p>ISAPI extension modules (.dll files) are written by third
parties. The Apache Group does not author these modules, so we
provide no support for them. Please contact the ISAPI's author
directly if you are experiencing problems running their ISAPI
extention. <strong>Please <em>do not</em> post such problems to
Apache's lists or bug reporting pages.</strong></p>
</summary>
<section><title>Usage</title> <p>In the server configuration file, use
the <directive module="mod_mime">AddHandler</directive> directive to
associate ISAPI files with the <code>isapi-isa</code> handler, and map
it to the with their file extensions. To enable any .dll file to be
processed as an ISAPI extention, edit the httpd.conf file and add the
following line:</p>
<example>
AddHandler isapi-isa .dll
</example>
<p>There is no capability within the Apache server to leave a
requested module loaded. However, you may preload and keep a
specific module loaded by using the following syntax in your
httpd.conf:</p>
<example>
ISAPICacheFile c:/WebWork/Scripts/ISAPI/mytest.dll
</example>
<p>Whether or not you have preloaded an ISAPI extension, all
ISAPI extensions are governed by the same permissions and
restrictions as CGI scripts. That is, <code>Options
ExecCGI</code> must be set for the directory that contains the
ISAPI .dll file.</p>
<p>Review the <a href="#notes">Additional Notes</a> and the <a
href="#journal">Programmer's Journal</a> for additional details
and clarification of the specific ISAPI support offered by
mod_isapi.</p>
</section>
<section id="notes"><title>Additional Notes</title>
<p>Apache's ISAPI implementation conforms to all of the ISAPI
2.0 specification, except for some "Microsoft-specific"
extensions dealing with asynchronous I/O. Apache's I/O model
does not allow asynchronous reading and writing in a manner
that the ISAPI could access. If an ISA tries to access
unsupported features, including async I/O, a message is placed
in the error log to help with debugging. Since these messages
can become a flood, the directive <code>ISAPILogNotSupported
Off</code> exists to quiet this noise.</p>
<p>Some servers, like Microsoft IIS, load the ISAPI extension
into the server and keep it loaded until memory usage is too
high, or unless configuration options are specified. Apache
currently loads and unloads the ISAPI extension each time it is
requested, unless the ISAPICacheFile directive is specified.
This is inefficient, but Apache's memory model makes this the
most effective method. Many ISAPI modules are subtly
incompatible with the Apache server, and unloading these
modules helps to ensure the stability of the server.</p>
<p>Also, remember that while Apache supports ISAPI Extensions,
it <strong>does not support ISAPI Filters.</strong> Support for
filters may be added at a later date, but no support is planned
at this time.</p>
</section>
<section id="journal"><title>Programmer's Journal</title>
<p>If you are programming Apache 2.0 <module>mod_isapi</module>
modules, you must limit your calls to ServerSupportFunction to the
following directives:</p>
<dl>
<dt>HSE_REQ_SEND_URL_REDIRECT_RESP</dt>
<dd>Redirect the user to another location.<br />
This must be a fully qualified URL (e.g.
http://server/location).</dd>
<dt>HSE_REQ_SEND_URL</dt>
<dd>Redirect the user to another location.<br />
This cannot be a fully qualified URL, you are not allowed to
pass the protocol or a server name (e.g. simply
/location).<br />
This redirection is handled by the server, not the
browser.<br />
<strong>Warning:</strong> in their recent documentation,
Microsoft appears to have abandoned the distinction between
the two HSE_REQ_SEND_URL functions. Apache continues to treat
them as two distinct functions with different requirements
and behaviors.</dd>
<dt>HSE_REQ_SEND_RESPONSE_HEADER</dt>
<dd>Apache accepts a response body following the header if it
follows the blank line (two consecutive newlines) in the
headers string argument. This body cannot contain NULLs,
since the headers argument is NULL terminated.</dd>
<dt>HSE_REQ_DONE_WITH_SESSION</dt>
<dd>Apache considers this a no-op, since the session will be
finished when the ISAPI returns from processing.</dd>
<dt>HSE_REQ_MAP_URL_TO_PATH</dt>
<dd>Apache will translate a virtual name to a physical
name.</dd>
<dt>HSE_APPEND_LOG_PARAMETER</dt>
<dd>
This logged message may be captured in any of the following
logs:
<ul>
<li>in the \"%{isapi-parameter}n\" component in a
CustomLog directive</li>
<li>in the %q log component with the
ISAPIAppendLogToQuery On directive</li>
<li>in the error log with the ISAPIAppendLogToErrors On
directive</li>
</ul>
The first option, the %{isapi-parameter}n component, is
always available and prefered.
</dd>
<dt>HSE_REQ_IS_KEEP_CONN</dt>
<dd>Will return the negotiated Keep-Alive status.</dd>
<dt>HSE_REQ_SEND_RESPONSE_HEADER_EX</dt>
<dd>Will behave as documented, although the fKeepConn flag is
ignored.</dd>
<dt>HSE_REQ_IS_CONNECTED</dt>
<dd>Will report false if the request has been aborted.</dd>
</dl>
<p>Apache returns FALSE to any unsupported call to
ServerSupportFunction, and sets the GetLastError value to
ERROR_INVALID_PARAMETER.</p>
<p>ReadClient retrieves the request body exceeding the initial
buffer (defined by ISAPIReadAheadBuffer). Based on the
ISAPIReadAheadBuffer setting (number of bytes to buffer prior
to calling the ISAPI handler) shorter requests are sent
complete to the extension when it is invoked. If the request is
longer, the ISAPI extension must use ReadClient to retrieve the
remaining request body.</p>
<p>WriteClient is supported, but only with the HSE_IO_SYNC flag
or no option flag (value of 0). Any other WriteClient request
will be rejected with a return value of FALSE, and a
GetLastError value of ERROR_INVALID_PARAMETER.</p>
<p>GetServerVariable is supported, although extended server
variables do not exist (as defined by other servers.) All the
usual Apache CGI environment variables are available from
GetServerVariable, as well as the ALL_HTTP and ALL_RAW
values.</p>
<p>Apache 2.0 <module>mod_isapi</module> supports additional
features introduced in later versions of the ISAPI specification,
as well as limited emulation of async I/O and the TransmitFile
semantics. Apache also supports preloading ISAPI .dlls for
performance, neither of which were not available under Apache 1.3
mod_isapi.</p>
</section>
<directivesynopsis>
<name>ISAPIFileChache</name>
<description>ISAPI .dll files to be loaded at startup</description>
<syntax>ISAPIFileCache <em>file-path</em> [<em>file-path</em>] ...</syntax>
<contextlist><context>server config</context></contextlist>
<usage>
<p>Specifies a space-separated list of file names to be loaded
when the Apache server is launched, and remain loaded until the
server is shut down. This directive may be repeated for every
ISAPI .dll file desired. The full path name of each file should
be specified.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>ISAPIReadAheadBuffer</name>
<description>Size of the Read Ahead Buffer sent to ISAPI
extensions</description>
<syntax>ISAPIReadAheadBuffer <em>size</em></syntax>
<default>ISAPIReadAheadBuffer 49152</default>
<contextlist><context>server config</context></contextlist>
<usage>
<p>Defines the maximum size of the Read Ahead Buffer sent to
ISAPI extensions when they are initially invoked. All remaining
data must be retrieved using the ReadClient callback; some
ISAPI extensions may not support the ReadClient function. Refer
questions to the ISAPI extension's author.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>ISAPILogNotSupported</name>
<description>Log unsupported feature requests from ISAPI
extensions</description>
<syntax>ISAPILogNotSupported on|off</syntax>
<default>ISAPILogNotSupported on</default>
<contextlist><context>server config</context></contextlist>
<usage>
<p>Logs all requests for unsupported features from ISAPI
extensions in the server error log. While this should be turned
off once all desired ISAPI modules are functioning, it defaults
to on to help administrators track down problems.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>ISAPIAppendLogToErrors</name>
<description>Record HSE_APPEND_LOG_PARAMETER requests from ISAPI
extensions to the error log</description>
<syntax>ISAPIAppendLogToErrors on|off</syntax>
<default>ISAPIAppendLogToErrors off</default>
<contextlist><context>server config</context></contextlist>
<usage>
<p>Record HSE_APPEND_LOG_PARAMETER requests from ISAPI
extensions to the server error log.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>ISAPIAppendLogToQuery</name>
<description>Record HSE_APPEND_LOG_PARAMETER requests from ISAPI
extensions to the query field</description>
<syntax>ISAPIAppendLogToQuery on|off</syntax>
<default>ISAPIAppendLogToQuery off</default>
<contextlist><context>server config</context></contextlist>
<usage>
<p>Record HSE_APPEND_LOG_PARAMETER requests from ISAPI
extensions to the query field (appended to the CustomLog %q
component).</p>
</usage>
</directivesynopsis>
</modulesynopsis>
1.1 httpd-2.0/docs/manual/mod/mod_mime_magic.xml
Index: mod_mime_magic.xml
===================================================================
<?xml version="1.0"?>
<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
<?xml-stylesheet type="text/xsl" href="../style/manual.xsl"?>
<modulesynopsis>
<name>mod_mime_magic</name>
<description>Determines the MIME type of a file
by looking at a few bytes of its contents</description>
<status>Extension</status>
<sourcefile>mod_mime_magic.c</sourcefile>
<identifier>mime_magic_module</identifier>
<summary>
<p>This module determines the MIME type of files in the same
way the Unix file(1) command works: it looks at the first few
bytes of the file. It is intended as a "second line of defense"
for cases that <module>mod_mime</module> can't
resolve. To assure that mod_mime gets first try at determining
a file's MIME type, be sure to list mod_mime_magic
<strong>before</strong> mod_mime in the configuration.</p>
<p>This module is derived from a free version of the
<code>file(1)</code> command for Unix, which uses "magic
numbers" and other hints from a file's contents to figure out
what the contents are. This module is active only if the magic
file is specified by the <directive module="mod_mime_magic"
>MimeMagicFile</directive> directive.</p>
</summary>
<section><title>Format of the Magic File</title>
<p>The contents of the file are plain ASCII text in 4-5
columns. Blank lines are allowed but ignored. Commented lines
use a hash mark "#". The remaining lines are parsed for the
following columns:</p>
<table border="1">
<tr valign="top">
<th>Column</th>
<th>Description</th>
</tr>
<tr valign="top">
<td>1</td>
<td>byte number to begin checking from<br />
">" indicates a dependency upon the previous non-">"
line</td>
</tr>
<tr valign="top">
<td>2</td>
<td>
type of data to match
<table border="1">
<tr>
<td>byte</td>
<td>single character</td>
</tr>
<tr>
<td>short</td>
<td>machine-order 16-bit integer</td>
</tr>
<tr>
<td>long</td>
<td>machine-order 32-bit integer</td>
</tr>
<tr>
<td>string</td>
<td>arbitrary-length string</td>
</tr>
<tr>
<td>date</td>
<td>long integer date (seconds since Unix
epoch/1970)</td>
</tr>
<tr>
<td>beshort</td>
<td>big-endian 16-bit integer</td>
</tr>
<tr>
<td>belong</td>
<td>big-endian 32-bit integer</td>
</tr>
<tr>
<td>bedate</td>
<td>big-endian 32-bit integer date</td>
</tr>
<tr>
<td>leshort</td>
<td>little-endian 16-bit integer</td>
</tr>
<tr>
<td>lelong</td>
<td>little-endian 32-bit integer</td>
</tr>
<tr>
<td>ledate</td>
<td>little-endian 32-bit integer date</td>
</tr>
</table>
</td>
</tr>
<tr valign="top">
<td>3</td>
<td>contents of data to match</td>
</tr>
<tr valign="top">
<td>4</td>
<td>MIME type if matched</td>
</tr>
<tr valign="top">
<td>5</td>
<td>MIME encoding if matched (optional)</td>
</tr>
</table>
<p>For example, the following magic file lines would recognize
some audio formats.</p>
<example>
<pre>
# Sun/NeXT audio data
0 string .snd
>12 belong 1 audio/basic
>12 belong 2 audio/basic
>12 belong 3 audio/basic
>12 belong 4 audio/basic
>12 belong 5 audio/basic
>12 belong 6 audio/basic
>12 belong 7 audio/basic
>12 belong 23 audio/x-adpcm
</pre>
</example>
<p>Or these would recognize the difference between "*.doc" files
containing Microsoft Word or FrameMaker documents. (These are
incompatible file formats which use the same file suffix.)</p>
<example>
<pre>
# Frame
0 string \<MakerFile application/x-frame
0 string \<MIFFile application/x-frame
0 string \<MakerDictionary application/x-frame
0 string \<MakerScreenFon application/x-frame
0 string \<MML application/x-frame
0 string \<Book application/x-frame
0 string \<Maker application/x-frame
# MS-Word
0 string \376\067\0\043 application/msword
0 string \320\317\021\340\241\261 application/msword
0 string \333\245-\0\0\0 application/msword
</pre>
</example>
<p>An optional MIME encoding can be included as a fifth column.
For example, this can recognize gzipped files and set the
encoding for them.</p>
<example>
<pre>
# gzip (GNU zip, not to be confused with [Info-ZIP/PKWARE] zip archiver)
0 string \037\213 application/octet-stream x-gzip
</pre>
</example>
</section>
<section><title>Performance Issues</title>
<p>This module is not for every system. If your system is barely
keeping up with its load or if you're performing a web server
benchmark, you may not want to enable this because the
processing is not free.</p>
<p>However, an effort was made to improve the performance of
the original file(1) code to make it fit in a busy web server.
It was designed for a server where there are thousands of users
who publish their own documents. This is probably very common
on intranets. Many times, it's helpful if the server can make
more intelligent decisions about a file's contents than the
file name allows ...even if just to reduce the "why doesn't my
page work" calls when users improperly name their own files.
You have to decide if the extra work suits your
environment.</p>
<p>When compiling an Apache server, this module should be at or
near the top of the list of modules in the Configuration file.
The modules are listed in increasing priority so that will mean
this one is used only as a last resort, just like it was
designed to.</p>
</section>
<section id="notes"><title>Notes</title>
<p>The following notes apply to the mod_mime_magic module and are
included here for compliance with contributors' copyright
restrictions that require their acknowledgment. </p>
<pre>
/*
* mod_mime_magic: MIME type lookup via file magic numbers
* Copyright (c) 1996-1997 Cisco Systems, Inc.
*
* This software was submitted by Cisco Systems to the Apache Group in July
* 1997. Future revisions and derivatives of this source code must
* acknowledge Cisco Systems as the original contributor of this module.
* All other licensing and usage conditions are those of the Apache Group.
*
* Some of this code is derived from the free version of the file command
* originally posted to comp.sources.unix. Copyright info for that program
* is included below as required.
* ---------------------------------------------------------------------------
* - Copyright (c) Ian F. Darwin, 1987. Written by Ian F. Darwin.
*
* This software is not subject to any license of the American Telephone and
* Telegraph Company or of the Regents of the University of California.
*
* Permission is granted to anyone to use this software for any purpose on any
* computer system, and to alter it and redistribute it freely, subject to
* the following restrictions:
*
* 1. The author is not responsible for the consequences of use of this
* software, no matter how awful, even if they arise from flaws in it.
*
* 2. The origin of this software must not be misrepresented, either by
* explicit claim or by omission. Since few users ever read sources, credits
* must appear in the documentation.
*
* 3. Altered versions must be plainly marked as such, and must not be
* misrepresented as being the original software. Since few users ever read
* sources, credits must appear in the documentation.
*
* 4. This notice may not be removed or altered.
* -------------------------------------------------------------------------
*
* For compliance with Mr Darwin's terms: this has been very significantly
* modified from the free "file" command.
* - all-in-one file for compilation convenience when moving from one
* version of Apache to the next.
* - Memory allocation is done through the Apache API's pool structure.
* - All functions have had necessary Apache API request or server
* structures passed to them where necessary to call other Apache API
* routines. (<em>i.e.</em>, usually for logging, files, or memory allocation in
* itself or a called function.)
* - struct magic has been converted from an array to a single-ended linked
* list because it only grows one record at a time, it's only accessed
* sequentially, and the Apache API has no equivalent of realloc().
* - Functions have been changed to get their parameters from the server
* configuration instead of globals. (It should be reentrant now but has
* not been tested in a threaded environment.)
* - Places where it used to print results to stdout now saves them in a
* list where they're used to set the MIME type in the Apache request
* record.
* - Command-line flags have been removed since they will never be used here.
*
*/
</pre>
</section>
<directivesynopsis>
<name>MimeMagicFile</name>
<description>Enable MIME-type determination based on file contents
using the specified magic file</description>
<syntax>MimeMagicFile <em>file-path</em></syntax>
<contextlist><context>server config</context>
<context>virtual host</context></contextlist>
<usage>
<p>The <directive>MimeMagicFile</directive> directive can be used to
enable this module, the default file is distributed at
<code>conf/magic</code>. Non-rooted paths are relative to the
ServerRoot. Virtual hosts will use the same file as the main
server unless a more specific setting is used, in which case
the more specific setting overrides the main server's file.</p>
</usage>
</directivesynopsis>
</modulesynopsis>
1.1 httpd-2.0/docs/manual/mod/mod_negotiation.xml
Index: mod_negotiation.xml
===================================================================
<?xml version="1.0"?>
<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
<?xml-stylesheet type="text/xsl" href="../style/manual.xsl"?>
<modulesynopsis>
<name>mod_negotiation</name>
<description>Provides for <a
href="../content-negotiation.html">content negotiation</a></description>
<status>Base</status>
<sourcefile>mod_negotiation.c</sourcefile>
<identifier>negotiation_module</identifier>
<summary>
<p>Content negotiation, or more accurately content selection, is
the selection of the document that best matches the clients
capabilities, from one of several available documents. There
are two implementations of this.</p>
<ul>
<li>A type map (a file with the handler
<code>type-map</code>) which explicitly lists the files
containing the variants.</li>
<li>A MultiViews search (enabled by the MultiViews <directive
module="core.html">Options</directive>, where the server does an
implicit filename pattern match, and choose from amongst the
results.</li>
</ul>
</summary>
<seealso><directive module="mod_mime">DefaultLangauge</directive></seealso>
<seealso><directive module="mod_mime">AddEncoding</directive></seealso>
<seealso><directive module="mod_mime">AddLanguage</directive></seealso>
<seealso><directive module="mod_mime">AddType</directive></seealso>
<section><title>Type maps</title>
<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 hash character ('#') 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>
<dl>
<dt>Content-Encoding:</dt>
<dd>The encoding of the file. Apache only recognizes
encodings that are defined by an <directive
module="mod_mime">AddEncoding</directive> directive.
This normally includes the encodings <code>x-compress</code>
for compress'd files, and <code>x-gzip</code> for gzip'd
files. The <code>x-</code> prefix is ignored for encoding
comparisons.</dd>
<dt>Content-Language:</dt>
<dd>The language of the variant, as an Internet standard
language tag (RFC 1766). An example is <code>en</code>,
meaning English.</dd>
<dt>Content-Length:</dt>
<dd>The length of the file, in bytes. If this header is not
present, then the actual length of the file is used.</dd>
<dt>Content-Type:</dt>
<dd>
The MIME media type of the document, with optional
parameters. Parameters are separated from the media type
and from one another by a semi-colon, with a syntax of
<code>name=value</code>. Common parameters include:
<dl>
<dt>level</dt>
<dd>an integer specifying the version of the media type.
For <code>text/html</code> this defaults to 2, otherwise
0.</dd>
<dt>qs</dt>
<dd>a floating-point number with a value in the range 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 if it
is attempting to represent a photograph. However, if the
resource being represented is ascii art, then an ascii
file would have a higher source quality than a jpeg file.
All qs values are therefore specific to a given
resource.</dd>
</dl>
Example:
<blockquote>
<code>Content-Type: image/jpeg; qs=0.8</code>
</blockquote>
</dd>
<dt>URI:</dt>
<dd>The path to the file containing this variant, relative to
the map file.</dd>
</dl>
</section>
<section><title>MultiViews</title>
<p>A MultiViews search is enabled by the MultiViews <directive
module="core">Options</directive>. If the server receives a
request for <code>/some/dir/foo</code> and
<code>/some/dir/foo</code> does <em>not</em> exist, then the
server reads the directory looking for all files named
<code>foo.*</code>, and effectively fakes 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>
</section>
<directivesynopsis>
<name>CacheNegotiatedDocs</name>
<description>Allows content-negotiated documents to be
cached by proxy servers</description>
<syntax>CacheNegotiatedDocs on|off</syntax>
<default>CacheNegotiatedDocs off</default>
<contextlist><context>server config</context></contextlist>
<compatibility>The syntax changed in version 2.0.</compatibility>
<usage>
<p>If set, this directive allows content-negotiated documents
to be cached by proxy servers. This could mean that clients
behind those proxys could retrieve versions of the documents
that are not the best match for their abilities, but it will
make caching more efficient.</p>
<p>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.</p>
<p>Prior to version 2.0,
<directive>CacheNegotiatedDocs</directive> did not take an
argument; it was turned on by the presence of the directive by
itself.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>ForceLangaugePriority</name>
<description>Action to take if a single acceptable document is not
found</description>
<syntax>ForceLanguagePriority None|Prefer|Fallback [Prefer|Fallback]</syntax>
<default>ForceLangaugePriority None</default>
<contextlist><context>server config</context>
<context>virtual host</context>
<context>directory</context>
<context>.htaccess</context>
</contextlist>
<override>FileInfo</override>
<compatibility>Available in version 2.0.30 and later</compatibility>
<usage>
<p>The <directive>ForceLanguagePriority</directive> directive uses
the given <directive
module="mod_negotiation">LanguagePriority</directive> to satisfy
negotation where the server could otherwise not return a single
matching document.</p>
<p><code>ForceLanguagePriority Prefer</code> uses
<code>LanguagePriority</code> to serve a 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 en and de
each as quality .500 (equally acceptable) then then first matching
variant, en, will be served.</p>
<example>
LanguagePriority en fr de<br />
ForceLanguagePriority Prefer
</example>
<p><code>ForceLanguagePriority Fallback</code> uses
<code>LanguagePriority</code> 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
es langauge response, but such a variant isn't found, then the
first variant from the LanguagePriority list below will be
served.</p>
<example>
LanguagePriority en fr de<br />
ForceLanguagePriority Fallback
</example>
<p>Both options, Prefer and Fallback, may be specified, so either the
first matching variant from LanguagePriority will be served if more
that one variant is acceptable, or first available document will be
served if none of the variants matched the client's acceptable list of
languages.</p>
</usage>
</directivesynopsis>
<directivesynopsis>
<name>LanguagePriority</name>
<description>The precendence of language variants for cases where
the client does not express a preference</description>
<syntax>LanguagePriority <em>MIME-lang</em> [<em>MIME-lang</em>] ...</syntax>
<contextlist><context>server config</context>
<context>virtual host</context>
<context>directory</context>
<context>.htaccess</context>
</contextlist>
<override>FileInfo</override>
<usage>
<p>The <directive>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 <em>MIME-lang</em> are in order of decreasing preference.
Example:</p>
<example>LanguagePriority en fr de</example>
<p>For a request for <code>foo.html</code>, where
<code>foo.html.fr</code> and <code>foo.html.de</code> both
existed, but the browser did not express a language preference,
then <code>foo.html.fr</code> would be returned.</p>
<p>Note that this directive only has an effect if a 'best'
language cannot be determined by any other means or the <directive
module="mod_negotiation">ForceLanguagePriority</directive> directive
is not <code>None</code>. Correctly implemented HTTP/1.1 requests
will mean this directive has no effect.</p>
</usage>
</directivesynopsis>
</modulesynopsis>