This module associates the request filename's extensions (e.g. .html) with the file's behavior (handlers and filters) and content (mime-type, language, character set and encoding.)
Status: Base
Source File: mod_mime.c
Module Identifier: mime_module
The directives AddHandler, AddOutputFilter, and AddInputFilter control the modules or scripts that serve the document.
In addition, mod_mime may define the "handler" for a document, which controls which module or script will serve the document. With the introduction of "filters" in Apache 2.0, mod_mime can also define the filters that the the content should be processed through (e.g. the Includes output filter for server side scripting) and what filters the client request and POST content should be processed through (the input filters.)
The directives AddCharset, AddEncoding, AddLanguage and AddType are all used to map file extensions onto the meta-information for that file. Respectively they set the character set, content-encoding, content-language, and MIME-type (content-type) of documents.
The directive TypesConfig is used to specify a
file which also maps extensions onto MIME types. Most administrators use
the provided mime.types file which associates common filename extensions
with IANA registered content types. The current list is maintained at
http://www.isi.edu/in-notes/iana/assignments/media-types/media-types
although it may be mirrored elsewhere). This simplifies the httpd.conf file
by providing the majority of media-type definitions, and they may be
overriden by AddType directives as needed.
Please do not send requests to the Apache httpd Project to add any new entries in the distributed mime.types file unless (1) they are already registered with IANA, and (2) they use widely accepted, non-conflicting filename extensions across platforms. category/x-subtype requests will be automatically rejected, as will any new two-letter extensions as they will likely conflict later with the already crowded language and character set namespace.
The core directives ForceType and SetHandler are used to associate all the files in a given container (e.g., <location>, <directory>, or <Files>) with a particular MIME-type or handler. These settings override any filename extension mappings defined in mod_mime.
Note that changing the type or encoding of a file does not change the
value of the Last-Modified
header. Thus, previously cached
copies may still be used by a client or proxy, with the previous headers.
If you change the meta-information (language, content type, character set
or encoding) you may need to 'touch' affected files (updating their last
modified date) to ensure that all visitors are receive the corrected
content headers.
See also: MimeMagicFile.
welcome.html.fr
maps onto content type text/html and
language French then the file welcome.fr.html
will map
onto exactly the same information. The only exception to this is if an
extension is given which Apache does not know how to handle. In this
case it will "forget" about any information it obtained from
extensions to the left of the unknown extension. So, for example, if
the extensions fr and html are mapped to the appropriate language and
type but extension xxx is not assigned to anything, then the file
welcome.fr.xxx.html
will be associated with content-type
text/html but no language.
If more than one extension is given which maps onto the same type of
meta-information, then the one to the right will be used. For example,
if ".gif" maps to the MIME-type image/gif and ".html" maps to the
MIME-type text/html, then the file welcome.gif.html
will
be associated with the MIME-type "text/html".
Care should be taken when a file with multiple extensions gets
associated with both a MIME-type and a handler. This will usually
result in the request being by the module associated with the
handler. For example, if the .imap
extension is mapped to
the handler "imap-file" (from mod_imap) and the .html
extension is mapped to the MIME-type "text/html", then the file
world.imap.html
will be associated with both the
"imap-file" handler and "text/html" MIME-type. When it is processed,
the "imap-file" handler will be used, and so it will be treated as a
mod_imap imagemap file.
The MIME RFC puts it this way:
The Content-Encoding entity-header field is used as a modifier to the media-type. When present, its value indicates what additional content coding has been applied to the resource, and thus what decoding mechanism must be applied in order to obtain the media-type referenced by the Content-Type header field. The Content-Encoding is primarily used to allow a document to be compressed without losing the identity of its underlying media type.By using more than one file extension (see section above about multiple file extensions), you can indicate that a file is of a particular type, and also has a particular encoding.
For example, you may have a file which is a Microsoft Word document, which is pkzipped to reduce its size. If the .doc extension is associated with the Microsoft Word file type, and the .zip extension is associated with the pkzip file encoding, then the file Resume.doc.zipwould be known to be a pkzip'ed Word document.
Apache send a Content-encoding header with the resource, in order to tell the client browser about the encoding method.
Content-encoding: pkzip
While the character set is useful for the browser, in order to determine how to display the document, the language and the character set are also used in the process of content negotiation (See mod_negotiation) to determine which document to give to the client, when there are alternative documents in more than one language, or more than one character set.
To convey this further information, Apache optionally sends a Content-Language header, to specify the language that the document is in, and can append additional information onto the Content-Type header to indicate the particular character set that should be used to correctly render the information.
Content-Language: en, fr Content-Type: text/plain; charset=ISO-8859-2
The language specification is the two-letter abbreviation for the language. The charset is the name of the particular character set which should be used.
The AddCharset directive maps the given filename extensions to the specified content charset. charset is the MIME charset parameter of filenames containing extension. This mapping is added to any already in force, overriding any mappings that already exist for the same extension.
Example:
AddLanguage ja .ja AddCharset EUC-JP .euc AddCharset ISO-2022-JP .jis AddCharset SHIFT_JIS .sjis
Then the document xxxx.ja.jis
will be treated as being a
Japanese document whose charset is ISO-2022-JP (as will the document
xxxx.jis.ja
). The AddCharset directive is useful for both
to inform the client about the character encoding of the document so
that the document can be interpreted and displayed appropriately, and
for content negotiation, where
the server returns one from several documents based on the client's
charset preference.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
See also: mod_negotiation
The AddEncoding directive maps the given filename extensions to the specified encoding type. MIME-enc is the MIME encoding to use for documents containing the extension. This mapping is added to any already in force, overriding any mappings that already exist for the same extension. Example:
AddEncoding x-gzip .gz
AddEncoding x-compress .Z
This will cause filenames containing the .gz extension to be marked as
encoded using the x-gzip encoding, and filenames containing the .Z
extension to be marked as encoded with x-compress.
Old clients expect x-gzip
and x-compress
,
however the standard dictates that they're equivalent to gzip
and compress
respectively. Apache does content encoding
comparisons by ignoring any leading x-
. When responding
with an encoding Apache will use whatever form (i.e., x-foo
or foo
) the client requested. If the client didn't
specifically request a particular form Apache will use the form given by
the AddEncoding
directive. To make this long story short,
you should always use x-gzip
and x-compress
for these two specific encodings. More recent encodings, such as
deflate
should be specified without the x-
.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
See also: Files with multiple extensions
AddHandler maps the filename extensions extension to the
handler handler-name. This
mapping is added to any already in force, overriding any mappings that
already exist for the same extension.
For example, to activate CGI scripts
with the file extension ".cgi
", you might use:
AddHandler cgi-script .cgi
Once that has been put into your srm.conf or httpd.conf file, any
file containing the ".cgi
" extension will be treated as a
CGI program.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
See also: Files with multiple extensions
Syntax: AddInputFilter filter[;filter...] extension [extension ...]
Default: none
Context: directory, files, location, .htaccess
Status: mod_mime
Compatibility: AddInputFilter is only available in
Apache 2.0.26 and later.
AddInputFilter maps the filename extensions extension to the filter or filters which will process client requests and POST input when they are received by the server. This is in addition to any filters defined elsewhere, including the SetInputFilter directive. This mapping is merged over any already in force, overriding any mappings that already exist for the same extension.
If more than one filter is specified, they must be seperated by semicolons in the order in which they should process the content. Both the filter and extension arguments are case-insensitive, and the extension may be specified with or without a leading dot.
See also the Filters documentation.
The AddLanguage directive maps the given filename extension to the specified content language. MIME-lang is the MIME language of filenames containing extension. This mapping is added to any already in force, overriding any mappings that already exist for the same extension.
Example:
AddEncoding x-compress .Z
AddLanguage en .en
AddLanguage fr
.fr
Then the document xxxx.en.Z
will be treated as being a
compressed English document (as will the document
xxxx.Z.en
). Although the content language is reported to
the client, the browser is unlikely to use this information. The
AddLanguage directive is more useful for
content negotiation, where
the server returns one from several documents based on the client's
language preference.
If multiple language assignments are made for the same extension, the last one encountered is the one that is used. That is, for the case of:
AddLanguage en .en AddLanguage en-uk .en AddLanguage en-us .en
documents with the extension ".en
" would be treated as
being "en-us
".
The extension argument is case-insensitive, and can be specified with or without a leading dot.
See also: Files with multiple extensions, mod_negotiation
Syntax: AddOutputFilter filter[;filter...] extension [extension ...]
Default: none
Context: directory, files, location, .htaccess
Status: mod_mime
Compatibility: AddOutputFilter is only available in
Apache 2.0.26 and later.
The AddOutputFilter
directive maps the filename extensions
extension to the filters which will process responses from the
server before they are sent to the client. This is in addition to any
filters defined elsewhere, including the
SetOutputFilter directive.
This mapping is merged over any already in force, overriding any
mappings that already exist for the same extension.
AddOutputFilter INCLUDES shtml
If more than one filter is specified, they must be seperated by semicolons in the order in which they should process the content. Both the filter and extension arguments are case-insensitive, and the extension may be specified with or without a leading dot.
See also the Filters documentation.
The AddType directive maps the given filename extensions onto the
specified content type. MIME-type is the MIME type to use for
filenames containing extension. This mapping is added to any
already in force, overriding any mappings that already exist for the
same extension. This directive can be used to add mappings
not listed in the MIME types file (see the TypesConfig
directive).
Example:
AddType image/gif .gif
It is recommended that new MIME types be added using the AddType directive
rather than changing the TypesConfig file.Note that, unlike the NCSA httpd, this directive cannot be used to set the type of particular files.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
See also: Files with multiple extensions
The DefaultLanguage directive tells Apache that all files in the
directive's scope (e.g., all files covered by the current
<Directory>
container) that don't have an explicit
language extension (such as .fr or .de as
configured by AddLanguage) should be considered to be in
the specified MIME-lang language. This allows entire
directories to be marked as containing Dutch content, for instance,
without having to rename each file. Note that unlike using extensions
to specify languages, DefaultLanguage can only specify a
single language.
If no DefaultLanguage directive is in force, and a file does not have any language extensions as configured by AddLanguage, then that file will be considered to have no language attribute.
See also: Files with multiple extensions, mod_negotiation
The RemoveCharset directive removes any
character set associations for files with the given extensions.
This allows .htaccess
files in subdirectories to undo
any associations inherited from parent directories or the server
config files.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
The RemoveEncoding directive removes any
encoding associations for files with the given extensions.
This allows .htaccess
files in subdirectories to undo
any associations inherited from parent directories or the server
config files. An example of its use might be:
/foo/.htaccess:
AddEncoding x-gzip .gz
AddType text/plain .asc
<Files *.gz.asc>
RemoveEncoding .gz
</Files>
This will cause foo.gz
to be marked as being encoded with the
gzip method, but foo.gz.asc
as an unencoded plaintext file.
Note:RemoveEncoding directives are processed after any AddEncoding directives, so it is possible they may undo the effects of the latter if both occur within the same directory configuration.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
The RemoveHandler directive removes any
handler associations for files with the given extensions.
This allows .htaccess
files in subdirectories to undo
any associations inherited from parent directories or the server
config files. An example of its use might be:
/foo/.htaccess:
AddHandler server-parsed .html
/foo/bar/.htaccess:
RemoveHandler .html
This has the effect of returning .html files in the /foo/bar directory to being treated as normal files, rather than as candidates for parsing (see the mod_include module).
The extension argument is case-insensitive, and can be specified with or without a leading dot.
The RemoveInputFilter directive removes any input filter
associations for files with the given extensions. This allows
.htaccess
files in subdirectories to undo any associations
inherited from parent directories or the server config files.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
The RemoveLanguage directive removes any
language associations for files with the given extensions.
This allows .htaccess
files in subdirectories to undo
any associations inherited from parent directories or the server
config files.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
The RemoveOutputFilter directive removes any output filter
associations for files with the given extensions. This allows
.htaccess
files in subdirectories to undo any associations
inherited from parent directories or the server config files.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
The RemoveType directive removes any
MIME type associations for files with the given extensions.
This allows .htaccess
files in subdirectories to undo
any associations inherited from parent directories or the server
config files. An example of its use might be:
/foo/.htaccess:
RemoveType .cgi
This will remove any special handling of .cgi
files in the
/foo/
directory and any beneath it, causing the files to be
treated as being of the default type.
Note:RemoveType
directives are processed after any
AddType
directives, so it is possible they may undo the effects
of the latter if both occur within the same directory configuration.
The extension argument is case-insensitive, and can be specified with or without a leading dot.
TypesConfig conf/mime.types
The TypesConfig directive sets the location of the MIME types configuration file. Filename is relative to the ServerRoot. This file sets the default list of mappings from filename extensions to content types; changing this file is not recommended. Use the AddType directive instead. The file contains lines in the format of the arguments to an AddType command:
MIME-type extension extension ...The extensions are lower-cased. Blank lines, and lines beginning with a hash character (`#') are ignored.