Apache Module mod_mime
Description: | Associates the requested filename's extensions with the file's behavior (handlers and filters) and content (mime-type, language, character set and encoding) |
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Status: | Base |
ModuleIdentifier: | mime_module |
SourceFile: | 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.
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>
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
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.
AddCharset Directive
Description: | Maps the given filename extensions to the specified content charset |
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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.
See also
AddEncoding Directive
Description: | Maps the given filename extensions to the specified encoding type |
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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.
AddHandler Directive
Description: | Maps the filename extensions to the specified handler |
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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 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. Filenames may have multiple extensions and the extension argument will be compared against each of them.
See also
AddInputFilter Directive
Description: | Maps filename extensions to the filters that will process client requests |
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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
AddLanguage Directive
Description: | Maps the given filename extension to the specified content language |
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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
AddOutputFilter Directive
Description: | Maps filename extensions to the filters that will process responses from the server |
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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>
See also
AddType Directive
Description: | Maps the given filename extensions onto the specified content type |
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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.
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 simmilar 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.
See also
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. |
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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., all resources 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 assigned a Content-Language of language-tag. This allows entire directory trees 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 no Content-Language header field will be generated.
Example
DefaultLanguage en
See also
ModMimeUsePathInfo Directive
Description: | Tells mod_mime to treat path_info components as part of the filename |
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Syntax: | ModMimeUsePathInfo On|Off |
Default: | ModMimeUsePathInfo Off |
Context: | directory |
Status: | Base |
Module: | mod_mime |
The ModMimeUsePathInfo
directive is used to combine the filename with the path_info
URL component to apply mod_mime
's directives to the request. The default value is Off
- therefore, the path_info
component is ignored.
This directive is recommended when you have a virtual filesystem.
Example
ModMimeUsePathInfo On
If you have a request for /index.php/foo.shtml
mod_mime
will now treat the incoming request as /index.php/foo.shtml
and directives like AddOutputFilter INCLUDES .shtml
will add the INCLUDES
filter to the request. If ModMimeUsePathInfo
is not set, the INCLUDES
filter will not be added. This will work analogously for virtual paths, such as those defined by <Location>
See also
MultiviewsMatch Directive
Description: | The types of files that will be included when searching for a matching file with MultiViews |
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Syntax: | MultiviewsMatch Any|NegotiatedOnly|Filters|Handlers [Handlers|Filters] |
Default: | MultiviewsMatch NegotiatedOnly |
Context: | server config, virtual host, directory, .htaccess |
Override: | FileInfo |
Status: | Base |
Module: | mod_mime |
MultiviewsMatch
permits three different behaviors for mod_negotiation's Multiviews feature. Multiviews allows a request for a file, e.g. index.html
, to match any negotiated extensions following the base request, e.g. index.html.en
, index.html.fr
, or index.html.gz
.
The NegotiatedOnly
option provides that every extension following the base name must correlate to a recognized mod_mime
extension for content negotiation, e.g. Charset, Content-Type, Language, or Encoding. This is the strictest implementation with the fewest unexpected side effects, and is the default behavior.
To include extensions associated with Handlers and/or Filters, set the MultiviewsMatch
directive to either Handlers
, Filters
, or both option keywords. If all other factors are equal, the smallest file will be served, e.g. in deciding between index.html.cgi
of 500 bytes and index.html.pl
of 1000 bytes, the .cgi
file would win in this example. Users of .asis
files might prefer to use the Handler option, if .asis
files are associated with the asis-handler
.
You may finally allow Any
extensions to match, even if mod_mime
doesn't recognize the extension. This can cause unpredictable results, such as serving .old or .bak files the webmaster never expected to be served.
For example, the following configuration will allow handlers and filters to participate in Multviews, but will exclude unknown files:
MultiviewsMatch Handlers Filters
MultiviewsMatch
is not allowed in a <Location>
or <LocationMatch>
section.
See also
RemoveCharset Directive
Description: | Removes any character set associations for a set of file extensions |
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Syntax: | RemoveCharset extension [extension] ... |
Context: | virtual host, directory, .htaccess |
Override: | FileInfo |
Status: | Base |
Module: | mod_mime |
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.
Example
RemoveCharset .html .shtml
RemoveEncoding Directive
Description: | Removes any content encoding associations for a set of file extensions |
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Syntax: | RemoveEncoding extension [extension] ... |
Context: | virtual host, directory, .htaccess |
Override: | FileInfo |
Status: | Base |
Module: | mod_mime |
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.
RemoveHandler Directive
Description: | Removes any handler associations for a set of file extensions |
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Syntax: | RemoveHandler extension [extension] ... |
Context: | virtual host, directory, .htaccess |
Override: | FileInfo |
Status: | Base |
Module: | mod_mime |
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.
RemoveInputFilter Directive
Description: | Removes any input filter associations for a set of file extensions |
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Syntax: | RemoveInputFilter extension [extension] ... |
Context: | virtual host, directory, .htaccess |
Override: | FileInfo |
Status: | Base |
Module: | mod_mime |
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.
See also
RemoveLanguage Directive
Description: | Removes any language associations for a set of file extensions |
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Syntax: | RemoveLanguage extension [extension] ... |
Context: | virtual host, directory, .htaccess |
Override: | FileInfo |
Status: | Base |
Module: | mod_mime |
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.
RemoveOutputFilter Directive
Description: | Removes any output filter associations for a set of file extensions |
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Syntax: | RemoveOutputFilter extension [extension] ... |
Context: | virtual host, directory, .htaccess |
Override: | FileInfo |
Status: | Base |
Module: | mod_mime |
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.
Example
RemoveOutputFilter shtml
See also
RemoveType Directive
Description: | Removes any content type associations for a set of file extensions |
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Syntax: | RemoveType extension [extension] ... |
Context: | virtual host, directory, .htaccess |
Override: | FileInfo |
Status: | Base |
Module: | mod_mime |
The RemoveType
directive removes any media 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 responses containing those files to omit the HTTP Content-Type header field.
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 Directive
Description: | The location of the mime.types file |
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Syntax: | TypesConfig file-path |
Default: | TypesConfig conf/mime.types |
Context: | server config |
Status: | Base |
Module: | mod_mime |
The TypesConfig
directive sets the location of the media types configuration file. File-path is relative to the ServerRoot
. This file sets the default list of mappings from filename extensions to content types. Most administrators use the mime.types
file provided by their OS, which associates common filename extensions with the official list of IANA registered media types maintained at http://www.iana.org/assignments/media-types/index.html as well as a large number of unofficial types. This simplifies the httpd.conf
file by providing the majority of media-type definitions, and may be overridden by AddType
directives as needed. You should not edit the mime.types
file, because it may be replaced when you upgrade your server.
The file contains lines in the format of the arguments to an AddType
directive:
media-type [extension] ...
The case of the extension does not matter. Blank lines, and lines beginning with a hash character (#
) are ignored. Empty lines are there for completeness (of the mime.types file). Apache httpd can still determine these types with mod_mime_magic
.
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.
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