<p><code>MultiViews</code> is a per-directory option, meaning it
can be set with an <code class="directive"><a href="./mod/core.html#options">Options</a></code>
directive within a <code class="directive"><a href="./mod/core.html#directory"><Directory></a></code>, <code class="directive"><a href="./mod/core.html#location"><Location></a></code> or <code class="directive"><a href="./mod/core.html#files"><Files></a></code> section in
<code>httpd.conf</code>, or (if <code class="directive"><a href="./mod/core.html#allowoverride">AllowOverride</a></code> is properly set) in
<code>.htaccess</code> files. Note that <code>Options All</code>
does not set <code>MultiViews</code>; you have to ask for it by
name.</p>
<p>The effect of <code>MultiViews</code> is as follows: if the
server receives a request for <code>/some/dir/foo</code>, if
<code>/some/dir</code> has <code>MultiViews</code> enabled, and
<code>/some/dir/foo</code> does <em>not</em> exist, then the
server reads the directory looking for files named foo.*, 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.</p>
<p><code>MultiViews</code> may also apply to searches for the file
named by the <code class="directive"><a href="./mod/mod_dir.html#directoryindex">DirectoryIndex</a></code> directive, if the
server is trying to index a directory. If the configuration files
<p>New in Apache 2.0, some exceptions have been added to the
negotiation algorithm to allow graceful fallback when language
negotiation fails to find a match.</p>
<p>When a client requests a page on your server, but the server
cannot find a single page that matches the Accept-language sent by
the browser, the server will return either a "No Acceptable
Variant" or "Multiple Choices" response to the client. To avoid
these error messages, it is possible to configure Apache to ignore
the Accept-language in these cases and provide a document that
does not explicitly match the client's request. The <code class="directive"><a href="./mod/mod_negotiation.html#forcelanguagepriority">ForceLanguagePriority</a></code>
directive can be used to override one or both of these error
messages and substitute the servers judgement in the form of the
<p>The server will also attempt to match language-subsets when no
other match can be found. For example, if a client requests
documents with the language <code>en-GB</code> for British
English, the server is not normally allowed by the HTTP/1.1
standard to match that against a document that is marked as simply
<code>en</code>. (Note that it is almost surely a configuration
error to include <code>en-GB</code> and not <code>en</code> in the
Accept-Language header, since it is very unlikely that a reader
understands British English, but doesn't understand English in
general. Unfortunately, many current clients have default
configurations that resemble this.) However, if no other language
match is possible and the server is about to return a "No
Acceptable Variants" error or fallback to the <code class="directive"><a href="./mod/mod_negotiation.html#languagepriority">LanguagePriority</a></code>, the server
will ignore the subset specification and match <code>en-GB</code>
against <code>en</code> documents. Implicitly, Apache will add
the parent language to the client's acceptable language list with
a very low quality value. But note that if the client requests
"en-GB; qs=0.9, fr; qs=0.8", and the server has documents
designated "en" and "fr", then the "fr" document will be returned.
This is necessary to maintain compliance with the HTTP/1.1
specification and to work effectively with properly configured
clients.</p>
<p>In order to support advanced techniques (such as Cookies or
special URL-paths) to determine the user's preferred language,
since Apache 2.0.47 <code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code> recognizes
the <a href="env.html">environment variable</a>
<code>prefer-language</code>. If it exists and contains an
appropriate language tag, <code class="module"><a href="./mod/mod_negotiation.html">mod_negotiation</a></code> will
try to select a matching variant. If there's no such variant,
<h2><a name="caching" id="caching">Note on Caching</a></h2>
<p>When a cache stores a representation, it associates it with
the request URL. The next time that URL is requested, the cache
can use the stored representation. But, if the resource is
negotiable at the server, this might result in only the first
requested variant being cached and subsequent cache hits might
return the wrong response. To prevent this, Apache normally
marks all responses that are returned after content negotiation
as non-cacheable by HTTP/1.0 clients. Apache also supports the
HTTP/1.1 protocol features to allow caching of negotiated
responses.</p>
<p>For requests which come from a HTTP/1.0 compliant client
(either a browser or a cache), the directive <code class="directive"><a href="./mod/mod_negotiation.html#cachenegotiateddocs">CacheNegotiatedDocs</a></code> can be
used to allow caching of responses which were subject to
negotiation. This directive can be given in the server config or
virtual host, and takes no arguments. It has no effect on requests
