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0N/A <
TITLE>Apache module mod_mime_magic</
TITLE>
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DIV ALIGN="CENTER">
0N/A <
H1 align="CENTER">Module mod_mime_magic</
H1>
2362N/A an optional extension to the Apache HTTPD server.
2362N/A It can be used to determine the MIME type of a file by looking at a
2362N/A few bytes of its contents, the same way the Unix file(1) command works.
0N/A To use mod_mime_magic you have to enable the following line in the
0N/A server build <
TT>Configuration</
TT> file:
0N/A This should be listed <
EM>before</
EM> mod_mime in the build
0N/A <
TT>Configuration</
TT> file so that it will be used after mod_mime.
0N/A mod_mime_magic is intended as a "second line of defense" for cases
0N/A mod_mime cannot resolve.
0N/A This module is derived from a free version of the <
CODE>file(1)</
CODE>
0N/A which uses "magic numbers" and other hints from a file's contents to
0N/A figure out what the contents are.
0N/A In the case of this module,
0N/A it tries to figure out the MIME type of the file.
0N/A This module active only if the magic file is specified by the
0N/A <
A HREF="#mimemagicfile"><
CODE>MimeMagicFile</
CODE></
A> directive.
0N/A The contents of the file are plain ASCII text in 4-5 columns.
0N/A Blank lines are allowed but ignored.
0N/A Commented lines use a hash mark "#".
0N/A The remaining lines are parsed for the following columns:
0N/A <
TH>Description</
TH>
0N/A <
TD>byte number to begin checking from
0N/A ">" indicates a dependency upon the previous non-">" line</
TD>
0N/A </
TR><
tr valign=top>
0N/A <
TD>type of data to match
0N/A <
TR><
TD>byte</
TD><
TD>single character</
TD></
TR>
0N/A <
TR><
TD>short</
TD><
TD>machine-order 16-bit integer</
TD></
TR>
0N/A <
TR><
TD>long</
TD><
TD>machine-order 32-bit integer</
TD></
TR>
0N/A <
TR><
TD>string</
TD><
TD>arbitrary-length string</
TD></
TR>
0N/A <
TR><
TD>date</
TD><
TD>long integer date
0N/A <
TR><
TD>beshort</
TD><
TD>big-endian 16-bit integer</
TD></
TR>
0N/A <
TR><
TD>belong</
TD><
TD>big-endian 32-bit integer</
TD></
TR>
0N/A <
TR><
TD>bedate</
TD><
TD>big-endian 32-bit integer date</
TD></
TR>
0N/A <
TR><
TD>leshort</
TD><
TD>little-endian 16-bit integer</
TD></
TR>
0N/A <
TR><
TD>lelong</
TD><
TD>little-endian 32-bit integer</
TD></
TR>
0N/A <
TR><
TD>ledate</
TD><
TD>little-endian 32-bit integer date</
TD></
TR>
0N/A </
TR><
tr valign=top>
0N/A <
TD>contents of data to match</
TD>
0N/A </
TR><
tr valign=top>
0N/A <
TD>MIME type if matched</
TD>
0N/A </
TR><
tr valign=top>
0N/A <
TD>MIME encoding if matched (optional)</
TD>
0N/A For example, the following magic file lines
0N/A would recognize some audio formats.
0N/A Or these would recognize the difference between "*.doc" files containing
0N/A Microsoft Word or FrameMaker documents. (These are incompatible file
0N/A formats which use the same file suffix.)
0N/A An optional MIME encoding can be included as a fifth column.
0N/A For example, this can recognize gzipped files and set the encoding
0N/A <
H3>Performance Issues</
H3>
0N/A This module is not for every system. If your system is barely keeping
0N/A up with its load or if you're performing a web server benchmark,
0N/A you may not want to enable this because the processing is not free.
0N/A However, an effort was made to improve the performance of the original
0N/A file(1) code to make it fit in a busy web server.
0N/A It was designed for a server where there are thousands of users who
0N/A publish their own documents.
0N/A This is probably very common on intranets.
0N/A Many times, it's helpful
0N/A if the server can make more intelligent decisions about a file's
0N/A contents than the file name allows
0N/A ...even if just to reduce the "why doesn't my page work" calls
0N/A when users improperly name their own files.
0N/A You have to decide if the extra work suits your environment.
0N/A When compiling an Apache server, this module should be at or near the
0N/A top of the list of modules in the Configuration file. The modules are
0N/A listed in increasing priority so that will mean this one is used only
0N/A as a last resort, just like it was designed to.
0N/A <
LI><
A HREF="#mimemagicfile">MimeMagicFile</
A>
0N/A <
H2><
A NAME="mimemagicfile">
0N/A ><
STRONG>Syntax:</
STRONG></
A> MimeMagicFile <
EM>magic-file-name</
EM>
0N/A ><
STRONG>Default:</
STRONG></
A> none
0N/A ><
STRONG>Context:</
STRONG></
A> server config, virtual host
0N/A ><
STRONG>Status:</
STRONG></
A> Extension
0N/A ><
STRONG>Module:</
STRONG></
A> mod_mime_magic
0N/A The <
CODE>MimeMagicFile</
CODE> directive can be used to enable this module,
0N/A Non-rooted paths are relative to the ServerRoot. Virtual hosts
0N/A will use the same file as the main server unless a more specific setting
0N/A is used, in which case the more specific setting overrides the main server's
0N/A <
H2><
A NAME="notes">Notes</
A></
H2>
0N/A The following notes apply to the mod_mime_magic module and are
0N/A included here for compliance with contributors' copyright restrictions
0N/A that require their acknowledgment.
0N/A * mod_mime_magic: MIME type lookup via file magic numbers
0N/A * Copyright (c) 1996-1997 Cisco Systems, Inc.
0N/A * This software was submitted by Cisco Systems to the Apache Group in July
0N/A * 1997. Future revisions and derivatives of this source code must
0N/A * acknowledge Cisco Systems as the original contributor of this module.
0N/A * All other licensing and usage conditions are those of the Apache Group.
0N/A * Some of this code is derived from the free version of the file command
0N/A * is included below as required.
0N/A * ---------------------------------------------------------------------------
0N/A * - Copyright (c) Ian F. Darwin, 1987. Written by Ian F. Darwin.
0N/A * This software is not subject to any license of the American Telephone and
0N/A * Telegraph Company or of the Regents of the University of California.
0N/A * Permission is granted to anyone to use this software for any purpose on any
0N/A * computer system, and to alter it and redistribute it freely, subject to
0N/A * the following restrictions:
0N/A * 1. The author is not responsible for the consequences of use of this
0N/A * software, no matter how awful, even if they arise from flaws in it.
0N/A * 2. The origin of this software must not be misrepresented, either by
0N/A * explicit claim or by omission. Since few users ever read sources, credits
0N/A * must appear in the documentation.
0N/A * 3. Altered versions must be plainly marked as such, and must not be
0N/A * misrepresented as being the original software. Since few users ever read
0N/A * sources, credits must appear in the documentation.
0N/A * 4. This notice may not be removed or altered.
0N/A * -------------------------------------------------------------------------
0N/A * For compliance with Mr Darwin's terms: this has been very significantly
0N/A * modified from the free "file" command.
0N/A * - all-in-one file for compilation convenience when moving from one
0N/A * version of Apache to the next.
0N/A * - Memory allocation is done through the Apache API's pool structure.
0N/A * - All functions have had necessary Apache API request or server
0N/A * structures passed to them where necessary to call other Apache API
0N/A * routines. (<
EM>
i.e.</
EM>, usually for logging, files, or memory allocation in
0N/A * itself or a called function.)
0N/A * - struct magic has been converted from an array to a single-ended linked
0N/A * list because it only grows one record at a time, it's only accessed
0N/A * sequentially, and the Apache API has no equivalent of realloc().
0N/A * - Functions have been changed to get their parameters from the server
0N/A * configuration instead of globals. (It should be reentrant now but has
0N/A * not been tested in a threaded environment.)
0N/A * - Places where it used to print results to stdout now saves them in a
0N/A * list where they're used to set the MIME type in the Apache request
0N/A * - Command-line flags have been removed since they will never be used here.
