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<div id="preamble"><h1>Apache Module mod_mime_libmagic</h1>
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<table class="module"><tr><th><a href="module-dict.html#Description">Description:</a></th><td>Determines the MIME type of a file from its contents
    using libmagic</td></tr>
<tr><th><a href="module-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="module-dict.html#ModuleIdentifier">Module&nbsp;Identifier:</a></th><td>mime_libmagic_module</td></tr>
<tr><th><a href="module-dict.html#SourceFile">Source&nbsp;File:</a></th><td>mod_mime_libmagic.c</td></tr>
<tr><th><a href="module-dict.html#Compatibility">Compatibility:</a></th><td>Available in Apache 2.5.1 and later</td></tr></table>
<h3>Summary</h3>

    <p>This module determines the <a class="glossarylink" href="../glossary.html#mime-type" title="see glossary">MIME
    type</a> of a file by examining its contents, in the same
    way the <code>file(1)</code> command does. It is intended as a
    "second line of defense" for files which
    <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> cannot type from their extension: it
    runs after <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> and does nothing if a type
    has already been set.</p>

    <p>Unlike <code class="module"><a href="../mod/mod_mime_magic.html">mod_mime_magic</a></code>, which has its own
    copy of the <code>file(1)</code> engine and its own magic
    database, this module uses the system's <code>libmagic(3)</code>
    library and magic database from the <code>file</code> package,
    so the types it reports are those which <code>file --mime-type</code>
    would report. The module is built only if libmagic is found at
    configure time, and is only active in a server or virtual host
    where <code class="directive"><a href="#mimelibmagic">MimeLibmagic</a></code>
    is <code>On</code>.</p>

    <p>Where libmagic reports <code>application/octet-stream</code>
    the module sets no type, leaving the response without a
    <code>Content-Type</code> header, as <code class="module"><a href="../mod/mod_mime_magic.html">mod_mime_magic</a></code>
    does for unrecognised content. Directories are typed as
    <code>httpd/unix-directory</code> and empty files as
    <code>text/plain</code>.</p>

    <p>The module does not look inside compressed files and never
    sets a <code>Content-Encoding</code>: a gzip file is reported as
    <code>application/gzip</code>. This differs from
    <code class="module"><a href="../mod/mod_mime_magic.html">mod_mime_magic</a></code>, which reports the compressed
    file's encoding.</p>
</div>
<div id="quickview"><h3>Topics</h3>
<ul id="topics">
<li><img alt="" src="../images/down.gif"> <a href="#threads">Performance and memory overhead</a></li>
</ul><h3 class="directives">Directives</h3>
<ul id="toc">
<li><img alt="" src="../images/down.gif"> <a href="#mimelibmagic">MimeLibmagic</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#mimelibmagicbytes">MimeLibmagicBytes</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#mimelibmagiccharset">MimeLibmagicCharset</a></li>
<li><img alt="" src="../images/down.gif"> <a href="#mimelibmagicfile">MimeLibmagicFile</a></li>
</ul>
<h3>Bugfix checklist</h3><ul class="seealso"><li><a href="https://www.apache.org/dist/httpd/CHANGES_2.4">httpd changelog</a></li><li><a href="https://bz.apache.org/bugzilla/buglist.cgi?bug_status=__open__&amp;list_id=144532&amp;product=Apache%20httpd-2&amp;query_format=specific&amp;order=changeddate%20DESC%2Cpriority%2Cbug_severity&amp;component=mod_mime_libmagic">Known issues</a></li><li><a href="https://bz.apache.org/bugzilla/enter_bug.cgi?product=Apache%20httpd-2&amp;component=mod_mime_libmagic">Report a bug</a></li></ul><h3>See also</h3>
<ul class="seealso">
<li><code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code></li>
<li><code class="module"><a href="../mod/mod_mime_magic.html">mod_mime_magic</a></code></li>
</ul></div>
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<div class="section">
<h2 id="threads">Performance and memory overhead <a title="Permanent link" href="#threads" class="permalink">&para;</a></h2>

    <p>A libmagic handle is created, loaded with the magic database
    and destroyed for every request examined. Loading a compiled database
    (<code>magic.mgc</code>) maps the file into memory rather than
    parsing it, and the mapped pages are shared between all server
    processes, so this is inexpensive. If the configured database
    is a text file rather than a compiled one, it is parsed on every
    request.</p>

    <p>Only the first <code class="directive"><a href="#mimelibmagicbytes">MimeLibmagicBytes</a></code> bytes of a file are read and
    examined, whatever its size.</p>

    <p>Examining text content in particular can allocate a few
    megabytes of memory temporarily. With a threaded MPM and a C
    library which keeps a separate heap per thread, each server
    thread retains its peak allocation, so the resident size of a
    busy child process can grow by that much per thread before
    levelling off. This is not a leak.</p>
</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="directive-section"><h2 id="mimelibmagic"><span id="MimeLibmagic">MimeLibmagic</span> Directive <a title="Permanent link" href="#mimelibmagic" class="permalink">&para;</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Enable MIME type determination from file contents</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MimeLibmagic On|Off</code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MimeLibmagic Off</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_mime_libmagic</td></tr>
</table>
    <p>The <code class="directive">MimeLibmagic</code> directive enables the
    module for a server or virtual host. Files which
    <code class="module"><a href="../mod/mod_mime.html">mod_mime</a></code> leaves untyped, typically those without
    a recognised extension, then have their contents examined by
    libmagic.</p>

    <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">MimeLibmagic On</pre>
</div>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="directive-section"><h2 id="mimelibmagicbytes"><span id="MimeLibmagicBytes">MimeLibmagicBytes</span> Directive <a title="Permanent link" href="#mimelibmagicbytes" class="permalink">&para;</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Number of bytes of a file examined</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MimeLibmagicBytes <var>bytes</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MimeLibmagicBytes 16384</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_mime_libmagic</td></tr>
</table>
    <p>The <code class="directive">MimeLibmagicBytes</code> directive sets
    how many bytes from the start of a file are read and examined.
    Larger values allow magic rules which look deeper into a file to
    match, at the cost of reading more of every examined file. The
    maximum is 1048576.</p>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="directive-section"><h2 id="mimelibmagiccharset"><span id="MimeLibmagicCharset">MimeLibmagicCharset</span> Directive <a title="Permanent link" href="#mimelibmagiccharset" class="permalink">&para;</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>Add a charset parameter to text types</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MimeLibmagicCharset On|Off</code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>MimeLibmagicCharset Off</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_mime_libmagic</td></tr>
</table>
    <p>When <code class="directive">MimeLibmagicCharset</code> is
    <code>On</code>, the character encoding libmagic detects (such
    as <code>us-ascii</code>, <code>utf-8</code> or
    <code>iso-8859-1</code>) is added as a <code>charset</code>
    parameter to <code>text/*</code> types, giving for example
    <code>text/plain; charset=utf-8</code>. Other types are not
    affected. As with <code class="directive"><a href="../mod/core.html#adddefaultcharset">AddDefaultCharset</a></code>, the detected charset should be
    trusted only where the content is known to be encoded
    consistently.</p>

</div>
<div class="top"><a href="#page-header"><img alt="top" src="../images/up.gif"></a></div>
<div class="directive-section"><h2 id="mimelibmagicfile"><span id="MimeLibmagicFile">MimeLibmagicFile</span> Directive <a title="Permanent link" href="#mimelibmagicfile" class="permalink">&para;</a></h2>
<table class="directive">
<tr><th><a href="directive-dict.html#Description">Description:</a></th><td>The magic database to use</td></tr>
<tr><th><a href="directive-dict.html#Syntax">Syntax:</a></th><td><code>MimeLibmagicFile <var>file-path</var></code></td></tr>
<tr><th><a href="directive-dict.html#Default">Default:</a></th><td><code>The default database of the installed libmagic</code></td></tr>
<tr><th><a href="directive-dict.html#Context">Context:</a></th><td>server config, virtual host</td></tr>
<tr><th><a href="directive-dict.html#Status">Status:</a></th><td>Extension</td></tr>
<tr><th><a href="directive-dict.html#Module">Module:</a></th><td>mod_mime_libmagic</td></tr>
</table>
    <p>The <code class="directive">MimeLibmagicFile</code> directive names
    the magic database, in place of the default compiled into
    libmagic (typically <code>/usr/share/misc/magic</code>, for which
    the compiled <code>magic.mgc</code> alongside it is loaded).
    The database must be in the format described in
    <code>magic(5)</code>; the file distributed with
    <code class="module"><a href="../mod/mod_mime_magic.html">mod_mime_magic</a></code> is not suitable. A relative path
    is taken relative to the <code class="directive"><a href="../mod/core.html#serverroot">ServerRoot</a></code>. If the database cannot be loaded, an
    error is logged for each request examined and the file is left
    untyped.</p>

    <p>Note that the <code>MAGIC</code> environment variable, if set
    when the server is started, overrides the library default, but
    not a database given with this directive.</p>

    <div class="example"><h3>Example</h3><pre class="prettyprint lang-config">MimeLibmagicFile /usr/share/misc/magic.mgc</pre>
</div>

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