The MIME type registry is located in /usr/gnome/share/mime-info. The MIME type registry contains the following files:
File |
Filename Extension |
---|---|
MIME information file |
.mime |
MIME keys file |
.keys |
The following sections describe MIME information files and MIME keys files.
MIME information files associate MIME types with one or both of the following:
Filename extensions
Filename patterns
When an application searches for the MIME type of a file, the application checks the filename against the MIME information files. If a match for the filename is found, the MIME type associated with the extension or pattern is the MIME type of the file.
In MIME information files, the filename pattern to search for is written as a regular expression.
The format of MIME type entries in MIME information files is as follows:
MIME-type ext[,priority]: list-of-extensions regex[,priority]: list-of-regular-expressions
You can specify a priority value for the filename extension and the regular expression. You can use the priority value to differentiate composite filenames. For example, you can assign a priority of 1 to the .gz extension, and assign a higher priority of 2 to the .tar.gz extension. In this case, the file abc.tar.gz takes the MIME type for .tar.gz.
You must indent the ext field and the regex field with a tab character (\t).
The following MIME type entries are samples from the gnome-vfs.mime MIME information file:
application/x-compressed-tar regex,2: tar\.gz$ ext: tgz audio/x-real-audio ext: rm ra ram image/jpeg ext: jpe jpeg jpg image/png ext: png text/html ext: html htm HTML text/plain ext: asc txt TXT text/x-readme regex: README.*
The file manager reads the MIME information files alphabetically. The alphabetical order determines the order in which MIME types are assigned to filename extensions or regular expressions. For example, if the same file extension is assigned to different MIME types in the files abc.mime and def.mime, the MIME type in abc.mime is used.
MIME keys file provide information about a MIME type that is used in the user interface. For example, the MIME keys file provides a description of a MIME type, and specifies an icon to represent files of that MIME type.
The following is a sample from a MIME keys file:
text/html description=HTML page icon_filename=gnome-text-html default_action_type=application short_list_application_ids_for_novice_user_level=mozilla,netscape,galeon category=Documents/World Wide Web
You must indent the keys in a MIME keys file with a tab character (\t).
Table 4–2 describes the most important keys in MIME keys files. Typically, the description key and the category key are localized.
Table 4–2 Keys in MIME Keys Files
Key |
Description |
---|---|
can_be_executable |
Specifies whether files of this MIME type can be executed. |
description |
Describes the MIME type. This description can be displayed in the file manager and other applications. |
icon_filename |
Specifies the filename of an icon to represent the MIME type. Does not specify the path to the filename, or the filename extension. This icon can be displayed in the file manager and other applications. |
default_action_type |
Specifies the category of action to take when a file of this MIME type is opened by the user. Enter application for this MIME type for most applications. |
short_list_application_ids _for_novice_user_level |
Specifies the application to use when a file of this MIME type is opened by a user. Specify one or more applications, in order of priority. The applications must also be registered in the application registry. |
category |
Specifies a category for the MIME type. The value
of this key determines the location of the MIME type in the |