docs/manual/mod/mod_dir.xml

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<modulesynopsis metafile="mod_dir.xml.meta">
<name>mod_dir</name>
<description>Provides for "trailing slash" redirects and
    serving directory index files</description>
<status>Base</status>
<sourcefile>mod_dir.c</sourcefile>
<identifier>dir_module</identifier>

<summary>
    <p>The index of a directory can come from one of two sources:</p>

    <ul>
      <li>A file written by the user, typically called
      <code>index.html</code>. The <directive module="mod_dir"
      >DirectoryIndex</directive> directive sets the
      name of this file. This is controlled by
      <module>mod_dir</module>.</li>

      <li>Otherwise, a listing generated by the server. This is
      provided by <module>mod_autoindex</module>.</li>
    </ul>
    <p>The two functions are separated so that you can completely
    remove (or replace) automatic index generation should you want
    to.</p>

    <p>A "trailing slash" redirect is issued when the server
    receives a request for a URL
    <code>http://servername/foo/dirname</code> where
    <code>dirname</code> is a directory. Directories require a
    trailing slash, so <module>mod_dir</module> issues a redirect to
    <code>http://servername/foo/dirname/</code>.</p>
</summary>

<directivesynopsis>
<name>DirectoryIndex</name>
<description>List of resources to look for when the client requests
a directory</description>
<syntax>DirectoryIndex
    disabled | <var>local-url</var> [<var>local-url</var>] ...</syntax>
<default>DirectoryIndex index.html</default>
<contextlist><context>server config</context><context>virtual host</context>
<context>directory</context><context>.htaccess</context></contextlist>
<override>Indexes</override>

<usage>
    <p>The <directive>DirectoryIndex</directive> directive sets the
    list of resources to look for, when the client requests an index
    of the directory by specifying a / at the end of the directory
    name.  <var>Local-url</var> is the (%-encoded) URL of a document on
    the server relative to the requested directory; it is usually the
    name of a file in the directory. Several URLs may be given, in
    which case the server will return the first one that it finds.  If
    none of the resources exist and the <code>Indexes</code> option is
    set, the server will generate its own listing of the
    directory.</p>

    <example><title>Example</title>
    <highlight language="config">
      DirectoryIndex index.html
      </highlight>
    </example>

    <p>then a request for <code>http://example.com/docs/</code> would
    return <code>http://example.com/docs/index.html</code> if it
    exists, or would list the directory if it did not.</p>

    <p>Note that the documents do not need to be relative to the
    directory;</p>

    <highlight language="config">
      DirectoryIndex index.html index.txt  /cgi-bin/index.pl
    </highlight>

    <p>would cause the CGI script <code>/cgi-bin/index.pl</code> to be
    executed if neither <code>index.html</code> or <code>index.txt</code>
    existed in a directory.</p>

    <p>A single argument of "disabled" prevents <module>mod_dir</module> from
    searching for an index.  An argument of "disabled" will be interpreted
    literally if it has any arguments before or after it, even if they are "disabled"
    as well.</p>

    <note>Multiple <directive>DirectoryIndex</directive>
    directives within the <a href="../sections.html"><em>same context</em></a> will add
    to the list of resources to look for rather than replace:
    </note>
    <highlight language="config">
# Example A: Set index.html as an index page, then add index.php to that list as well.
&lt;Directory "/foo"&gt;
    DirectoryIndex index.html
    DirectoryIndex index.php
&lt;/Directory&gt;

# Example B: This is identical to example A, except it's done with a single directive.
&lt;Directory "/foo"&gt;
    DirectoryIndex index.html index.php
&lt;/Directory&gt;

# Example C: To replace the list, you must explicitly reset it first:
# In this example, only index.php will remain as an index resource.
&lt;Directory "/foo"&gt;
    DirectoryIndex index.html
    DirectoryIndex disabled
    DirectoryIndex index.php
&lt;/Directory&gt;
    </highlight>

</usage>
</directivesynopsis>

<directivesynopsis>
<name>DirectoryIndexRedirect</name>
<description>Configures an external redirect for directory indexes.
</description>
<syntax>DirectoryIndexRedirect on | off | permanent | temp | seeother |
<var>3xx-code</var>
</syntax>
<default>DirectoryIndexRedirect off</default>
<contextlist><context>server config</context><context>virtual host</context>
<context>directory</context><context>.htaccess</context></contextlist>
<override>Indexes</override>
<compatibility>Available in version 2.3.14 and later</compatibility>

<usage>
    <p>By default, the <directive>DirectoryIndex</directive> is selected
    and returned transparently to the client.  <directive
    >DirectoryIndexRedirect</directive> causes an external redirect
    to instead be issued.</p>

    <p>The argument can be:</p>
    <ul>
     <li><code>on</code>: issues a 302 redirection to the index resource.</li>
     <li><code>off</code>: does not issue a redirection. This is the legacy behavior of mod_dir.</li>
     <li><code>permanent</code>: issues a 301 (permanent) redirection to the index resource.</li>
     <li><code>temp</code>: this has the same effect as <code>on</code></li>
     <li><code>seeother</code>: issues a 303 redirection (also known as "See Other") to the index resource.</li>
     <li><var>3xx-code</var>: issues a redirection marked by the chosen 3xx code.</li>
    </ul>


    <example><title>Example</title>
    <highlight language="config">
      DirectoryIndexRedirect on
      </highlight>
    </example>

    <p>A request for <code>http://example.com/docs/</code> would
    return a temporary redirect to <code
    >http://example.com/docs/index.html</code>
    if it exists.</p>

</usage>
</directivesynopsis>


<directivesynopsis>
<name>DirectorySlash</name>
<description>Toggle trailing slash redirects on or off</description>
<syntax>DirectorySlash On|Off|NotFound</syntax>
<default>DirectorySlash On</default>
<contextlist><context>server config</context><context>virtual host</context>
<context>directory</context><context>.htaccess</context></contextlist>
<override>Indexes</override>
<compatibility>Argument NotFound added in 2.5.1</compatibility>

<usage>
    <p>The <directive>DirectorySlash</directive> directive determines how 
    <module>mod_dir</module> should fixup URLs pointing to a directory or
    not.</p>

    <p>Typically if a user requests a resource without a trailing slash, which
    points to a directory, <module>mod_dir</module> redirects them to the same
    resource, but <em>with</em> trailing slash for some good reasons:</p>

    <ul>
    <li>The user is finally requesting the canonical URL of the resource</li>
    <li><module>mod_autoindex</module> works correctly. Since it doesn't emit
    the path in the link, it would point to the wrong path.</li>
    <li><directive module="mod_dir">DirectoryIndex</directive> will be evaluated
    <em>only</em> for directories requested with trailing slash.</li>
    <li>Relative URL references inside html pages will work correctly.</li>
    </ul>

    <p>If you don't want this effect <em>and</em> the reasons above don't
    apply to you, you can turn off the redirect as shown below. However,
    be aware that there are possible security implications to doing
    this.</p>

    <highlight language="config">
# see security warning below!
&lt;Location "/some/path"&gt;
    DirectorySlash Off
    SetHandler some-handler
&lt;/Location&gt;
    </highlight>

    <note type="warning"><title>Security Warning</title>
    <p>Turning off the trailing slash redirect may result in an information
    disclosure. Consider a situation where <module>mod_autoindex</module> is
    active (<code>Options +Indexes</code>) and <directive module="mod_dir"
    >DirectoryIndex</directive> is set to a valid resource (say,
    <code>index.html</code>) and there's no other special handler defined for
    that URL. In this case a request with a trailing slash would show the
    <code>index.html</code> file. <strong>But a request without trailing slash
    would list the directory contents</strong>.</p>
    </note>
	<p>Also note that some browsers may erroneously change POST requests into GET
	(thus discarding POST data) when a redirect is issued.</p>

    <p>To avoid the risks of the "off" behavior above, or to avoid disclosing 
    that a directory is present via the behavior of "on", an argument of 
    "NotFound" can be used to tell <module>mod_dir</module> to return an HTTP 
    404 status code instead of redirecting the request to include a trailing slash.</p>

</usage>
</directivesynopsis>
<directivesynopsis>
<name>FallbackResource</name>
<description>Define a default URL for requests that don't map to a file or handler</description>
<syntax>FallbackResource disabled | <var>local-url</var></syntax>
<default>disabled - httpd will return 404 (Not Found)</default>
<contextlist><context>server config</context><context>virtual host</context>
<context>directory</context><context>.htaccess</context></contextlist>
<override>Indexes</override>
<compatibility>The <code>disabled</code> argument is available in version 2.4.4 and
later</compatibility>
<usage>
    <p>Use this to set a handler for any URL that doesn't map to anything
    in your filesystem, and would otherwise return HTTP 404 (Not Found).
    For example</p>
    <highlight language="config">
        FallbackResource /not-404.php
    </highlight>
    <p>will cause requests for non-existent files to be handled by
    <code>not-404.php</code>, while requests for files that exist
    are unaffected.</p>
    <p>It is frequently desirable to have a single file or resource
    handle all requests to a particular directory, except those requests
    that correspond to an existing file or script. This is often
    referred to as a 'front controller.'</p>
    <p>In earlier versions of httpd, this effect typically required
    <module>mod_rewrite</module>, and the use of the <code>-f</code> and
    <code>-d</code> tests for file and directory existence. This now
    requires only one line of configuration.</p>
    <highlight language="config">
        FallbackResource /index.php
    </highlight>
    <p>Existing files, such as images, css files, and so on, will be
    served normally.</p>
    <p>Use the <code>disabled</code> argument to disable that feature
    if inheritance from a parent directory is not desired.</p>
    <p>In a sub-URI, such as <em>http://example.com/blog/</em> this
    <em>sub-URI</em> has to be supplied as <var>local-url</var>:</p>
    <highlight language="config">
&lt;Directory "/web/example.com/htdocs/blog"&gt;
    FallbackResource /blog/index.php
&lt;/Directory&gt;
&lt;Directory "/web/example.com/htdocs/blog/images"&gt;
    FallbackResource disabled
&lt;/Directory&gt;
    </highlight>
    <p>A fallback handler (in the above case, <code>/blog/index.php</code>)
    can access the original requested URL via the server variable
    <code>REQUEST_URI</code>. For example, to access this variable in PHP,
    use <code>$_SERVER['REQUEST_URI']</code>.</p>
    <note><title>Interaction with other handlers</title>
    <p><directive>FallbackResource</directive> only takes effect when no
    other handler has been assigned to the request. If a directive such as
    <directive module="core">SetHandler</directive> or
    <directive module="mod_mime">AddHandler</directive> has already
    assigned a handler to a URL or file extension,
    <directive>FallbackResource</directive> will not override it. For
    example, if you use
    <code>SetHandler application/x-httpd-php</code> in a
    <directive type="section" module="core">Directory</directive> section,
    that handler applies to all requests in that directory — even requests
    for non-existent files — so <directive>FallbackResource</directive>
    will never be invoked.</p></note>
</usage>
<seealso><directive module="core">SetHandler</directive></seealso>
<seealso><directive module="mod_mime">AddHandler</directive></seealso>
<seealso><directive module="mod_dir">DirectoryCheckHandler</directive></seealso>
</directivesynopsis>
<directivesynopsis>
<name>DirectoryCheckHandler</name>
<description>Toggle how this module responds when another handler is configured</description>
<syntax>DirectoryCheckHandler On|Off</syntax>
<default>DirectoryCheckHandler Off</default>
<contextlist><context>server config</context><context>virtual host</context>
<context>directory</context><context>.htaccess</context></contextlist>
<override>Indexes</override>
<compatibility>Available in 2.4.8 and later.  Releases prior to 2.4 implicitly
act as if "DirectoryCheckHandler ON" was specified.</compatibility>
<usage>
    <p>The <directive>DirectoryCheckHandler</directive> directive determines
    whether <module>mod_dir</module> should check for directory indexes or
    add trailing slashes when some other handler has been configured for
    the current URL. Handlers can be set by directives such as
    <directive module="core">SetHandler</directive> or by other modules at
    runtime. </p>

    <p>When set to <code>On</code>, <module>mod_dir</module> will
    take no action if another handler has already been configured
    for the URL.</p>

    <p>When set to <code>Off</code> (the default), <module>mod_dir</module>
    will process the request regardless of any other handler that may be
    configured. This allows directory indexes to be served even when a
    <directive>SetHandler</directive> directive is specified for an entire
    directory, but it can also result in conflicts with other modules.</p>
</usage>
</directivesynopsis>

</modulesynopsis>