MIME Types Overview

A Multipurpose Internet Mail Extension (MIME) type identifies the format of a file. Applications such as Internet browsers and email applications use the MIME type of a file to determine the actions to perform on the file.

For example, the file manager needs to know the MIME type of a file to perform the following tasks:

• Open the file in an appropriate application

• Display a string that describes the type of file

• Display an appropriate icon to represent the file

• Display a list of other applications that can open the file

MIME types were originally proposed as a standard for identifying the message body of an email message. Many systems use MIME types to identify the format of arbitrary files on the file system.

MIME types are composed of a top-level media type followed by a subtype identifier, separated by a forward slash character (/). An example of a MIME type is image/jpeg. The media type in this example is image and the subtype identifier is jpeg. The top-level media type is a general categorization about the content of the file, while the subtype identifer specifically identifies the format of the file. For more information about the supported media types and the corresponding subtypes, see MIME Media Types at the IANA web site.

The implementation of MIME types in the Oracle Solaris Desktop follows the XDG shared mime info specification. This specification provides the following advantages:

• Standard locations for all MIME related files

• Standard way for applications to register information about a new MIME type

• Standard way to retrieve the MIME type for a file

• Standard way to retrieve information about a MIME type

The following sections in this chapter describe the files and directories that make up the MIME database, details about source XML files, how to create or modify MIME types, how to register applications as handlers for certain MIME types, and how to add an application to the Oracle Solaris Desktop.