Tired of sending those drab textual notifications and newsletters to your friend and clients? Ever wanted to send attachments and/or HTML embedded email.

The answer is MIME. The ensuing few pages explain the basics of MIME, creating MIME-compliant messages and then ends with a working class implementation of sending MIME complaint email in PHP. Note that references to calling script, caller etc. denote the script that uses the class we are about to develop and client/MUA etc. denote a mail reading client or mail user agent.

MIME stand for Multipurpose Internet Mail Extensions. MIME extends the basic text-oriented Internet mail system in order that messages can contain binary attachments.

MIME takes advantage of the fact that RFC 822 places little restriction on the message body content: the only stipulation is that plain ASCII text be used. Thus, MIME messages consist of normal Internet text mail with some special RFC 822 compliant headers and formatted bodies (with the attachments represented in a subset of ASCII). These MIME headers give a special meaning to the presence of attachments in your mail.

An ordinary text e-mail message contains a header portion (To: From: Subject: etc.) and a body portion (Hello Mr., etc.). In a MIME compliant message, there are also headers involved and not surprisingly, parts of the email called MIME parts, prefixed by special headers also. A MIME mail is just an extension of the RFC 822 based email. It however has its own set of RFCs.

MIME headers are broadly classified as MIME Message Headers and MIME Part Headers, based on their placement in an email packet.

The MIME Message Headers are:

MIME part headers (headers that appear in the actual MIME "attachment" part), can have any of the above except the MIME-Version header. If a MIME header is part of the message block, it applies to the entire message. E.g., if Content-Transfer-Encoding appears in the Message header, it applies to the entire message body, but if it appears under a MIME part, it is applicable to only that part.