MimeCheck

You need Java to use MimeCheck.

MIME is also a way of specifying the format of web documents and attached email documents. The webserver gives two hints to the browser what sort of data it is sending it: the extension in the filename, and the MIME type in the HTTP header. The web server usually derives the MIME type by looking at a table of file extensions. If the web server fails to do this, often the file contents are just displayed as gibberish rather than properly acted on. In Novell Servers there is only one such extension-to-MIME translation table per server, not one per website hosted. Just send an email to your ISP telling them the extensions you need to support and the corresponding MIME types. In particular, you must tell your ISP to set up associations from extension to MIME type for all the Java file types such as .class, .java, .jar, .jnlp, .jardiff and .ser.

MIME types are referred to in the RFC 1945 HTTP 1.0 specification as media types. The content-type and content-encoding fields in the HTTP header together give a hint to the receiver what kind of data has just been handed to it.

IANA is responsible for assigning new MIME types. Unfortunately naming is even more chaotic than the extensions, often with several conflicting MIME types for each extension. Unfortunately, MIME has made the problem it was intended to solve even worse. It matters not what the official name is, but the MIME name configured in the majority of the world’s browsers is. I have found Filext.com the most useful source.

The Printable Problem

• 7bit (unencoded, case-insensitive, the data are all represented as short lines of US-ASCII data)
• quoted-printable (best used when message is mostly plain text with a few strange characters)
• base64
• uuencode
• 8bit (unencoded, the lines are short, but there may be non-ASCII characters)
• binary (unencoded, any characters, lines may be long) not used in practice.
• x-token

Eventually this printable encoding will be dropped. Base64 encoding, for example, adds 33% overhead to the transmitted message size. The Internet is now almost completely converted to 8-bit, so it should not usually be necessary.

MIME Types For A Java Website

HTML forms use application/x-www-form-urlencoded, though there is no filename.

MIME Hate

• The whole MIME scheme is disorganised. What determines how your browser displays, executes or downloads any given URL depends on its extension, the MIME type the website assigned that extension, the MIME type your browser assigned that extension, and the MIME type your operating system assigned that extension, the program your browser assigned to that MIME type and the program your operating system assigned to that MIME type, and probably the current phase of the moon.
• There is no way to attach a MIME type to a file. It has to be generated from the extension anyway with tables maintained on the server. There is no way to deal with files with different MIME types but the same extension anyway. MIME fails in its primary objective.
• Some websites ignore MIMEs entirely and call everything text/plain.
• There are duplicate MIME names for the same file type.
• There is no official list of MIME names anywhere.
• There is no one in charge of assigning MIME names. IANA supposedly is, but they don’t seem to keep properly formatted records about MIME names, their extensions and uses, they don’t assign names to avoid duplicates.
• There are many file types without assigned MIME names.
• MIME names are long-winded.
• MIME 7-bit encoding wastes bandwidth.
• MIME types are mapped from extensions to MIME types on a global, one-size-fits-all website-wide basis. The whole point of MIME types was to resolve the ambiguity of the same extension being used for two different purposes. To work properly MIME types need to be attached to files, just the way their human names are.

MIME Sources

You can get the MIME type for a given file using java.net.FileNameMap.getContentTypeFor(filename)

Here is one offial source for MIME types: The definitive IANA list however it has only a fraction of the total is use. Lantech List with some descriptions.

Configuring the Server

Programs To Handle Video and Audio Streams

Video Links Legend
streaming or downloadable
Click corresponding icon to download player.
Apple QuickTime
BitTorrent
DivX
DVD
Flash animations
Google
Microsoft Media Player
Microsoft Power Point
mp3
mp4
Real Player
VHS tape
transcript
unknown
You Tube

Audio Links Legend
streaming or downloadable
Click corresponding icon to download player.
Real Audio
compressed mp3
super compressed mp4
Microsoft Media Player
MIDI music files
uncompressed au
Microsoft uncompressed wav
unknown
transcript

JAF built-in MIME Types

1. Programmatically added entries to the MimetypesFileTypeMap instance.
2. The file .mime.types in the user’s home directory.
3. The file C:\Program Files\java\jre1.6.0_06/lib/mime.types.
4. The resource named META-INF/mime.types.
5. The resource named META-INF/mimetypes.default in the activation.jar file.

Learning More

• RFC 1521 (obsolete): MIME part 1
• RFC 1522 (obsolete): MIME part 2, non ASCII
• RFC 2045 MIME Part One: Format of Internet Message Bodies, specifies the various headers used to describe the structure of MIME messages.
• RFC 2046 MIME Part Two: Media Types, describes the general structure of the MIME media typing system and defines an initial set of media types.
• RFC 2047 MIME Part Three: Message Header Extensions for non-ASCII text
• RFC 2048 MIME Part Four: Registration Procedures
• RFC 2049 MIME Part Five: Conformance Criteria and Examples, Provides some illustrative examples of MIME message formats