Multipurpose Internet Mail Extensions
lastmod 2022-10-05created 2015-03-1212 edits
MIME (Multipurpose Internet Mail Extensions) is an Internet standard format for email. Because email is transmitted using 7-bit ASCII characters, characters that use codes of 8 bits or more and binary files are converted to the MIME format and sent over SMTP. In practice, most email sent over SMTP is in MIME format. The content types defined in the MIME standard are used in communication protocols such as HTTP, and their importance is steadily growing.
Categories
- MIME:List - List of MIME Types.
- MIME:Python - Implementing MIME in Python.
Overview
By default, SMTP, the Internet email transfer protocol, supports only 7-bit ASCII characters. This means that email written in languages other than English that cannot be represented in 7-bit ASCII cannot be transmitted properly. MIME defines a way to send email in languages other than English using non-ASCII character encodings. It also makes it possible to send 8-bit binary files such as pictures, music, movies, and computer programs by email. MIME is also a basic component of communication protocols such as HTTP that use messages in a format similar to email. Converting messages to MIME format is done automatically by the email program or on the server.
The basic format of email is defined in RFC 2821. This document replaces RFC 822. It specifies the format of the header and body of text email, including the familiar headers such as "To:", "Subject:", "From:", and "Date:". MIME defines additional email headers such as content-type, which indicates the kind of message, and content-transfer-encoding, which indicates how the message is encoded. MIME also specifies how non-ASCII characters can be used in email headers.
MIME is extensible. The MIME standard defines a way to register new content-types and other MIME attribute values.
One of MIME's explicit goals is compatibility with existing email systems. Non-MIME messages can be displayed properly in clients that support MIME, and conversely, simple MIME messages can be displayed in clients that do not support MIME.
About MIME (ver.naver)
As computing environments expanded from text-based to multimedia environments, email systems were also extended to accommodate new kinds of data. In particular, extending the functionality is essential for transmitting the languages of various countries that 7-bit ASCII code does not support, as well as data such as executable files in binary format, images, and audio. MIME (Multipurpose Internet Mail Extensions) was introduced to meet this need and is used universally in today's email environment.
Troubleshooting
Is a form like */jpeg valid?
- Stackoverflow - Is '*' a valid wildcard for a content type according to HTTP spec?
- Stackoverflow - Wildcard MIME subtype
Is it valid to specify type and subtype like */jpeg, using a Wildcard (*) for type?
Not sure yet. See the media type wiki. Needs more research.