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This lesson covers protocols for MIME.
MIME
- Multi-Purpose Internet Mail Extensions
- Internet standard that extends the format of email messages to support text in character sets other than ASCII, as well as attachments of audio, video, images, and application programs.
- Message bodies may consist of multiple parts, and header information may be specified in non-ASCII character sets.
- Email messages with MIME formatting are typically transmitted with standard protocols, such as
- Simple Mail Transfer Protocol (SMTP)
- Post Office Protocol (POP), and
- Internet Message Access Protocol (IMAP).
- In the HyperText Transfer Protocol (HTTP) for the World Wide Web, servers insert a MIME header field at the beginning of any Web transmission.
- Clients use the content type or media type header to select an appropriate viewer application for the type of data indicated.
- MIME header fields
- MIME-Version: 1.0
- Content-Type: text/plain
- text/html, image/jpeg, audio/mp3, video/mp4, and application/msword
- https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
- Content-Disposition: attachment; filename=genome.jpeg; modification-date=”Wed, 12 Feb 1997 16:29:51 -0500”;
- an inline content disposition
- automatically displayed when the message is displayed, or
- an attachment content disposition
- not displayed automatically and requires some form of action from the user to open it
- Some mail user agents did not follow this fully
- an inline content disposition
- Content-Transfer-Encoding
- set of methods for representing binary data in formats other than ASCII text format
- It indicates whether or not a binary-to-text encoding scheme has been used on top of the original encoding as specified within the Content-Type header:
- If such a binary-to-text encoding method has been used, it states which one.
- If not, it provides a descriptive label for the format of content, with respect to the presence of 8-bit or binary content.