Content Types

Every part has a content type, which identifies the type of content that is stored in the part. Content types define a media type, a subtype, and an optional set of parameters. Package implementers shall only create and only recognize parts with a content type; format designers shall specify a content type for each part included in the format. Content types for package parts shall fit the definition and syntax for media types as specified in RFC 2616, §3.7. [M1.13] This definition is as follows:

media-type = type "/" subtype *( ";" parameter )

where parameter is expressed as

attribute "=" value

The type, subtype, and parameter attribute names are case-insensitive. Parameter values may be case-sensitive, depending on the semantics of the parameter attribute name.

Content types shall not use linear white space either between the type and subtype or between an attribute and its value. Content types also shall not have leading or trailing white spaces. Package implementers shall create only such content types and shall require such content types when retrieving a part from a package; format designers shall specify only such content types for inclusion in the format. [M1.14]

The package implementer shall require a content type that does not include comments and the format designer shall specify such a content type. [M1.15]

Format designers might restrict the usage of parameters for content types. [O1.2]

Content types for package-specific parts are defined in Annex F, “Standard Namespaces and Content Types.”