2.4.x/docs/manual/mod/mod_info.xml

<?xml version="1.0"?>
<!DOCTYPE modulesynopsis SYSTEM "../style/modulesynopsis.dtd">
<?xml-stylesheet type="text/xsl" href="../style/manual.en.xsl"?>
<!-- $LastChangedRevision$ -->

<!--
 Licensed to the Apache Software Foundation (ASF) under one or more
 contributor license agreements.  See the NOTICE file distributed with
 this work for additional information regarding copyright ownership.
 The ASF licenses this file to You under the Apache License, Version 2.0
 (the "License"); you may not use this file except in compliance with
 the License.  You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
-->

<modulesynopsis metafile="mod_info.xml.meta">

<name>mod_info</name>
<description>Provides a comprehensive overview of the server
configuration</description>
<status>Extension</status>
<sourcefile>mod_info.c</sourcefile>
<identifier>info_module</identifier>

<summary>
    <p>To configure <module>mod_info</module>, add the following to your
    <code>httpd.conf</code> file.</p>

    <highlight language="config">
&lt;Location "/server-info"&gt;
    SetHandler server-info
&lt;/Location&gt;
    </highlight>

    <p>You may wish to use <module>mod_authz_host</module> inside the
    <directive type="section" module="core">Location</directive>
    directive to limit access to your server configuration
    information:</p>

    <highlight language="config">
&lt;Location "/server-info"&gt;
    SetHandler server-info
    Require host example.com
&lt;/Location&gt;
    </highlight>

    <p>Once configured, the server information is obtained by
    accessing <code>http://your.host.example.com/server-info</code></p>
</summary>

<section id="security"><title>Security Issues</title>
    <p>Once <module>mod_info</module> is loaded into the server, its
    handler capability is available in <em>all</em> configuration
    files, including per-directory files (<em>e.g.</em>,
    <code>.htaccess</code>). This may have security-related
    ramifications for your site.</p>

    <p>In particular, this module can leak sensitive information
    from the configuration directives of other Apache modules such as
    system paths, usernames/passwords, database names, etc. Therefore,
    this module should <strong>only</strong> be
    used in a controlled environment and always with caution.</p>

    <p>You will probably want to use <module>mod_authz_host</module>
    to limit access to your server configuration information.</p>

    <example><title>Access control</title>
    <highlight language="config">
&lt;Location "/server-info"&gt;
    SetHandler server-info
    # Allow access from server itself
    Require ip 127.0.0.1

    # Additionally, allow access from local workstation
    Require ip 192.168.1.17
&lt;/Location&gt;
      </highlight>
    </example>
</section>

<section id="queries"><title>Selecting the information shown</title>
    <p>By default, the server information includes a list of
    all enabled modules, and for each module, a description of
    the directives understood by that module, the hooks implemented
    by that module, and the relevant directives from the current
    configuration.</p>

    <p>Other views of the configuration information are available by
    appending a query to the <code>server-info</code> request. For
    example, <code>http://your.host.example.com/server-info?config</code>
    will show all configuration directives.</p>

    <dl>
        <dt><code>?&lt;module-name&gt;</code></dt>
            <dd>Only information relevant to the named module</dd>
        <dt><code>?config</code></dt>
            <dd>Just the configuration directives, not sorted by module</dd>
        <dt><code>?hooks</code></dt>
            <dd>Only the list of Hooks each module is attached to</dd>
        <dt><code>?list</code></dt>
            <dd>Only a simple list of enabled modules</dd>
        <dt><code>?server</code></dt>
            <dd>Only the basic server information</dd>
    </dl>
</section>

<section id="startup"><title>Dumping the configuration on startup</title>
    <p>If the config define <code>-DDUMP_CONFIG</code> is set,
    <module>mod_info</module> will dump the pre-parsed configuration to
    <code>stdout</code> during server startup. Pre-parsed means that
    directives like
    <directive type="section" module="core">IfDefine</directive> and
    <directive type="section" module="core">IfModule</directive> are
    evaluated and environment varialbles are replaced. However it does
    not represent the final state of the configuration. In particular,
    it does not represent the merging or overriding that may happen
    for repeated directives.</p>

    <p>This is roughly equivalent to the <code>?config</code> query.</p>
</section>

<section id="limitations"><title>Known Limitations</title>
    <p><module>mod_info</module> provides its information by reading the
    parsed configuration, rather than reading the original configuration
    file. There are a few limitations as a result of the way the parsed
    configuration tree is created:</p>
    <ul>
      <li>Directives which are executed immediately rather than being
          stored in the parsed configuration are not listed. These include
          <directive module="core">ServerRoot</directive>,
          <directive module="mod_so">LoadModule</directive>, and
          <directive module="mod_so">LoadFile</directive>.</li>
      <li>Directives which control the configuration file itself, such as
          <directive module="core">Include</directive>,
          <directive module="core" type="section">IfModule</directive> and
          <directive module="core" type="section">IfDefine</directive> are not
          listed, but the included configuration directives are.</li>
      <li>Comments are not listed. (This may be considered a feature.)</li>
      <li>Configuration directives from <code>.htaccess</code> files are
          not listed (since they do not form part of the permanent server
          configuration).</li>
      <li>Container directives such as
          <directive module="core" type="section">Directory</directive>
          are listed normally, but <module>mod_info</module> cannot figure
          out the line number for the closing
          <directive module="core" type="section" name="Directory">/Directory</directive>.</li>
      <li>Directives generated by third party modules such as <a href="http://perl.apache.org">mod_perl</a>
          might not be listed.</li>
    </ul>
</section>

<directivesynopsis>
<name>AddModuleInfo</name>
<description>Adds additional information to the module
information displayed by the server-info handler</description>
<syntax>AddModuleInfo <var>module-name</var> <var>string</var></syntax>
<contextlist><context>server config</context><context>virtual host</context>
</contextlist>

<usage>
    <p>This allows the content of <var>string</var> to be shown as
    HTML interpreted, <strong>Additional Information</strong> for
    the module <var>module-name</var>. Example:</p>

    <highlight language="config">
AddModuleInfo mod_deflate.c 'See &lt;a \
    href="http://httpd.apache.org/docs/&httpd.docs;/mod/mod_deflate.html"&gt;\
    http://httpd.apache.org/docs/&httpd.docs;/mod/mod_deflate.html&lt;/a&gt;'
    </highlight>
</usage>

</directivesynopsis>
</modulesynopsis>