# 12.19 `mimify` -- MIME processing of mail messages

The mimify module defines two functions to convert mail messages to and from MIME format. The mail message can be either a simple message or a so-called multipart message. Each part is treated separately. Mimifying (a part of) a message entails encoding the message as quoted-printable if it contains any characters that cannot be represented using 7-bit ASCII. Unmimifying (a part of) a message entails undoing the quoted-printable encoding. Mimify and unmimify are especially useful when a message has to be edited before being sent. Typical use would be:

      unmimify message
      edit message
      mimify message
      send message

The modules defines the following user-callable functions and user-settable variables:

`mimify` (infile, outfile)
  Copy the message in infile to outfile, converting parts to quoted-printable and adding MIME mail headers when necessary. infile and outfile can be file objects (actually, any object that has a `readline()` method (for infile) or a `write()` method (for outfile)) or strings naming the files. If infile and outfile are both strings, they may have the same value.

`unmimify` (infile, outfile[, decode_base64])
  Copy the message in infile to outfile, decoding all quoted-printable parts. infile and outfile can be file objects (actually, any object that has a `readline()` method (for infile) or a `write()` method (for outfile)) or strings naming the files. If infile and outfile are both strings, they may have the same value. If the decode_base64 argument is provided and tests true, any parts that are coded in the base64 encoding are decoded as well.

`mime_decode_header` (line)
  Return a decoded version of the encoded header line in line.

`mime_encode_header` (line)
  Return a MIME-encoded version of the header line in line.

`MAXLEN`
  By default, a part will be encoded as quoted-printable when it contains any non-ASCII characters (i.e., characters with the 8th bit set), or if there are any lines longer than `MAXLEN` characters (default value 200).

`CHARSET`
  When not specified in the mail headers, a character set must be filled in. The string used is stored in `CHARSET`, and the default value is ISO-8859-1 (also known as Latin1 (latin-one)).

This module can also be used from the command line. Usage is as follows:

      mimify.py -e [-l length] [infile [outfile]]
      mimify.py -d [-b] [infile [outfile]]

to encode (mimify) and decode (unmimify) respectively. infile defaults to standard input, outfile defaults to standard output. The same file can be specified for input and output.

If the -l option is given when encoding, if there are any lines longer than the specified length, the containing part will be encoded.

If the -b option is given when decoding, any base64 parts will be decoded as well.