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Apache > HTTP Server > Documentation > Version 2.4 > Modules

Apache Module mod_mime

Available Languages:  en  |  fr  |  ja 

Description:Associates the requested filename's extensions with the file's behavior (handlers and filters) and content (mime-type, language, character set and encoding)
Status:Base
Module Identifier:mime_module
Source File:mod_mime.c

Summary

This module is used to assign content metadata to the content selected for an HTTP response by mapping patterns in the URI or filenames to the metadata values. For example, the filename extensions of content files often define the content's Internet media type, language, character set, and content-encoding. This information is sent in HTTP messages containing that content and used in content negotiation when selecting alternatives, such that the user's preferences are respected when choosing one of several possible contents to serve. See mod_negotiation for more information about content negotiation.

The directives AddCharset, AddEncoding, AddLanguage and AddType are all used to map file extensions onto the metadata for that file. Respectively they set the character set, content-encoding, content-language, and media-type (content-type) of documents. The directive TypesConfig is used to specify a file which also maps extensions onto media types.

In addition, mod_mime may define the handler and filters that originate and process content. The directives AddHandler, AddOutputFilter, and AddInputFilter control the modules or scripts that serve the document. The MultiviewsMatch directive allows mod_negotiation to consider these file extensions to be included when testing Multiviews matches.

While mod_mime associates metadata with filename extensions, the core server provides directives that are used to associate all the files in a given container (e.g., <Location>, <Directory>, or <Files>) with particular metadata. These directives include ForceType, SetHandler, SetInputFilter, and SetOutputFilter. The core directives override any filename extension mappings defined in mod_mime.

Note that changing the metadata for 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 metadata (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.

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Files with Multiple Extensions

Files can have more than one extension; the order of the extensions is normally irrelevant. For example, if the file 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. If more than one extension is given that maps onto the same type of metadata, then the one to the right will be used, except for languages and content encodings. For example, if .gif maps to the media-type image/gif and .html maps to the media-type text/html, then the file welcome.gif.html will be associated with the media-type text/html.

Languages and content encodings are treated accumulative, because one can assign more than one language or encoding to a particular resource. For example, the file welcome.html.en.de will be delivered with Content-Language: en, de and Content-Type: text/html.

Care should be taken when a file with multiple extensions gets associated with both a media-type and a handler. This will usually result in the request being handled by the module associated with the handler. For example, if the .imap extension is mapped to the handler imap-file (from mod_imagemap) and the .html extension is mapped to the media-type text/html, then the file world.imap.html will be associated with both the imap-file handler and text/html media-type. When it is processed, the imap-file handler will be used, and so it will be treated as a mod_imagemap imagemap file.

If you would prefer only the last dot-separated part of the filename to be mapped to a particular piece of meta-data, then do not use the Add* directives. For example, if you wish to have the file foo.html.cgi processed as a CGI script, but not the file bar.cgi.html, then instead of using AddHandler cgi-script .cgi, use

Configure handler based on final extension only

<FilesMatch "[^.]+\.cgi$">
  SetHandler cgi-script
</FilesMatch>
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Content encoding

A file of a particular media-type can additionally be encoded a particular way to simplify transmission over the Internet. While this usually will refer to compression, such as gzip, it can also refer to encryption, such a pgp or to an encoding such as UUencoding, which is designed for transmitting a binary file in an ASCII (text) format.

The HTTP/1.1 RFC, section 14.11 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 codings have been applied to the entity-body, and thus what decoding mechanisms must be applied in order to obtain the media-type referenced by the Content-Type header field. 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.zip would be known to be a pkzip'ed Word document.

Apache sends a Content-encoding header with the resource, in order to tell the client browser about the encoding method.

Content-encoding: pkzip
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Character sets and languages

In addition to file type and the file encoding, another important piece of information is what language a particular document is in, and in what character set the file should be displayed. For example, the document might be written in the Vietnamese alphabet, or in Cyrillic, and should be displayed as such. This information, also, is transmitted in HTTP headers.

The character set, language, encoding and mime type are all 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 character set, language, encoding or mime type. All filename extensions associations created with AddCharset, AddEncoding, AddLanguage and AddType directives (and extensions listed in the MimeMagicFile) participate in this select process. Filename extensions that are only associated using the AddHandler, AddInputFilter or AddOutputFilter directives may be included or excluded from matching by using the MultiviewsMatch directive.

Charset

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-8859-1

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.

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AddCharset Directive

Description:Maps the given filename extensions to the specified content charset
Syntax:AddCharset charset extension [extension] ...
Context:server config, virtual host, directory, .htaccess
Override:FileInfo
Status:Base
Module:mod_mime

The AddCharset directive maps the given filename extensions to the specified content charset (the Internet registered name for a given character encoding). charset is the media type's charset parameter for resources with 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. Filenames may have multiple extensions and the extension argument will be compared against each of them.

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AddEncoding Directive

Description:Maps the given filename extensions to the specified encoding type
Syntax:AddEncoding encoding extension [extension] ...
Context:server config, virtual host, directory, .htaccess
Override:FileInfo
Status:Base
Module:mod_mime

The AddEncoding directive maps the given filename extensions to the specified HTTP content-encoding. encoding is the HTTP content coding to append to the value of the Content-Encoding header field for documents named with 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. Filenames may have multiple extensions and the extension argument will be compared against each of them.

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AddHandler Directive

Description:Maps the filename extensions to the specified handler
Syntax:AddHandler handler-name extension [extension] ...
Context:server config, virtual host, directory, .htaccess
Override:FileInfo
Status:Base
Module:mod_mime

Files having the name extension will be served by the specified 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 apache2.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. Filenames may have multiple extensions and the extension argument will be compared against each of them.

See also

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AddInputFilter Directive

Description:Maps filename extensions to the filters that will process client requests
Syntax:AddInputFilter filter[;filter...] extension [extension] ...
Context:server config, virtual host, directory, .htaccess
Override:FileInfo
Status:Base
Module:mod_mime

AddInputFilter maps the filename extension extension to the 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 separated by semicolons in the order in which they should process the content. The filter is case-insensitive.

The extension argument is case-insensitive and can be specified with or without a leading dot. Filenames may have multiple extensions and the extension argument will be compared against each of them.

See also

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AddLanguage Directive

Description:Maps the given filename extension to the specified content language
Syntax:AddLanguage language-tag extension [extension] ...
Context:server config, virtual host, directory, .htaccess
Override:FileInfo
Status:Base
Module:mod_mime

The AddLanguage directive maps the given filename extension to the specified content language. Files with the filename extension are assigned an HTTP Content-Language value of language-tag corresponding to the language identifiers defined by RFC 3066. This directive overrides 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-gb .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. Filenames may have multiple extensions and the extension argument will be compared against each of them.

See also

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AddOutputFilter Directive

Description:Maps filename extensions to the filters that will process responses from the server
Syntax:AddOutputFilter filter[;filter...] extension [extension] ...
Context:server config, virtual host, directory, .htaccess
Override:FileInfo
Status:Base
Module:mod_mime

The AddOutputFilter directive maps the filename extension 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 SetOutputFilter and AddOutputFilterByType directive. This mapping is merged over any already in force, overriding any mappings that already exist for the same extension.

For example, the following configuration will process all .shtml files for server-side includes and will then compress the output using mod_deflate.

AddOutputFilter INCLUDES;DEFLATE shtml

If more than one filter is specified, they must be separated by semicolons in the order in which they should process the content. The filter argument is case-insensitive.

The extension argument is case-insensitive and can be specified with or without a leading dot. Filenames may have multiple extensions and the extension argument will be compared against each of them.

Note that when defining a set of filters using the AddOutputFilter directive, any definition made will replace any previous definition made by the AddOutputFilter directive.

# Effective filter "DEFLATE"
AddOutputFilter DEFLATE shtml
<Location "/foo">
  # Effective filter "INCLUDES", replacing "DEFLATE"
  AddOutputFilter INCLUDES shtml
</Location>
<Location "/bar">
  # Effective filter "INCLUDES;DEFLATE", replacing "DEFLATE"
  AddOutputFilter INCLUDES;DEFLATE shtml
</Location>
<Location "/bar/baz">
  # Effective filter "BUFFER", replacing "INCLUDES;DEFLATE"
  AddOutputFilter BUFFER shtml
</Location>
<Location "/bar/baz/buz">
  # No effective filter, replacing "BUFFER"
  RemoveOutputFilter shtml
</Location>

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AddType Directive

Description:Maps the given filename extensions onto the specified content type
Syntax:AddType media-type extension [extension] ...
Context:server config, virtual host, directory, .htaccess
Override:FileInfo
Status:Base
Module:mod_mime

The AddType directive maps the given filename extensions onto the specified content type. media-type is the media 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.

It is recommended that new media types be added using the AddType directive rather than changing the TypesConfig file.

Example

AddType image/gif .gif

Or, to specify multiple file extensions in one directive:

Example

AddType image/jpeg jpeg jpg jpe

The extension argument is case-insensitive and can be specified with or without a leading dot. Filenames may have multiple extensions and the extension argument will be compared against each of them.

A similar effect to mod_negotiation's LanguagePriority can be achieved by qualifying a media-type with qs:

Example

AddType application/rss+xml;qs=0.8 .xml

This is useful in situations, e.g. when a client requesting Accept: */* can not actually processes the content returned by the server.

This directive primarily configures the content types generated for static files served out of the filesystem. For resources other than static files, where the generator of the response typically specifies a Content-Type, this directive has no effect.

Note

If no handler is explicitly set for a request, the specified content type will also be used as the handler name.

When explicit directives such as SetHandler or AddHandler do not apply to the current request, the internal handler name normally set by those directives is instead set to the content type specified by this directive.

This is a historical behavior that may be used by some third-party modules (such as mod_php) for taking responsibility for the matching request.

Configurations that rely on such "synthetic" types should be avoided. Additionally, configurations that restrict access to SetHandler or AddHandler should restrict access to this directive as well.

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DefaultLanguage Directive

Description:Defines a default language-tag to be sent in the Content-Language header field for all resources in the current context that have not been assigned a language-tag by some other means.
Syntax:DefaultLanguage language-tag
Context:server config, virtual host, directory, .htaccess
Override:FileInfo
Status:Base
Module:mod_mime

The DefaultLanguage directive tells Apache that all resources in the directive's scope (e.g.,