The last trick that we should cover regarding MIME messages is decoding headers that may have been
encoded with foreign languages. The function decode_header() takes a single header and returns a list of
pieces of the header; each piece is a binary string together with its encoding (named as a string if it is
something besides 7-bit ASCII, else the value None):
>>> x = '=?iso-8859-1?q?Michael_M=FCller?= <[email protected]>'
>>> import email.header
>>> pieces = email.header.decode_header(x)
>>> print pieces
[('Michael M\xfcller', 'iso-8859-1'), ('<[email protected]>', None)]
Of course, this raw information is likely to be of little use to you. To instead see the actual text inside
the encoding, use the decode() function of each binary string in the list (falling back to an ‘ascii’
encoding if None was returned) and paste the result together with spaces:
>>> print ' '.join( s.decode(enc or 'ascii') for s,enc in pieces )
Michael Müller <mmueller@example.com>
It is always good practice to use decode_header() on any of the “big three” headers —From, To, and
Subject —before displaying them to the user. If no special encoding was used, then the result will simply
be a one-element list containing the header string with a None encoding.