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databasemime-types

Maximum MIME type length when storing the type in a database

What are people using as the length of a MIME type field in their databases? The longest one we've seen so far is 72 bytes:

application/vnd.openxmlformats-officedocument.wordprocessingml.document

But I'm just waiting for a longer one. We're using 250 now, but has anyone seen a longer MIMEType than that?

Edit

From the accepted answer, 127 for type and sub-type each, so that's 254 max, plus the '/' is a limit of 255 for the combined value.

Solution

  • According to RFC 4288 "Media Type Specifications and Registration Procedures", type (eg. "application") and subtype (eg "vnd...") both can be max 127 characters. So including the slash, the maximum length is 255.

    Edit: Meanwhile, that document has been obsoleted by RFC 6838, which does not alter the maximum size but adds a remark:

    Also note that while this syntax allows names of up to 127 characters, implementation limits may make such long names problematic. For this reason, <type-name> and <subtype-name> SHOULD be limited to 64 characters.