How does encoding in email subjects work? (Django/ Python)

I am sending email with EmailMessage object to Gmail box.

The subject of an email looks something like this: u"You got a letter from Daėrius ęėįęėįęįėęįę---reply3_433441"

W开发者_开发技巧hen i receive an email, looking at the message info i can see that Subject line looks like this:

Subject: =?utf-8?b?WW91IGdvdCBhIGxldHRlciBmcm9tIERhxJdyaXVzIMSZxJfEr8SZxJfEr8SZ?= =?utf-8?b?xK/El8SZxK/EmS0tLXJlcGx5M180MzM0NDE=?=

How to decode this subject line?

I have sucesfully decoded email body (tex/plain) with this:

for part in msg.walk():
  if part.get_content_type() == 'text/plain':
    msg_encoding = part.get_content_charset()
    msg_text = part.get_payload().decode('quoted-printable')
msg_text = smart_unicode(msg_text, encoding=msg_encoding, strings_only=False, errors='strict') 

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See RFC 2047 for a complete description of the format of internationalized email headers. The basic format is "=?" charset "?" encoding "?" encoded-text "?=". So in your case, you have a base-64 encoded UTF-8 string.

You can use the email.header.decode_header and str.decode functions to decode it and get a proper Unicode string:

>>> import email.header
>>> x = email.header.decode_header('=?utf-8?b?WW91IGdvdCBhIGxldHRlciBmcm9tIERhxJdyaXVzIMSZxJfEr8SZxJfEr8SZ?=')
>>> x
[('You got a letter from Da\xc4\x97rius \xc4\x99\xc4\x97\xc4\xaf\xc4\x99\xc4\x97\xc4\xaf\xc4\x99', 'utf-8')]
>>> x[0][0].decode(x[0][1])
u'You got a letter from Da\u0117rius \u0119\u0117\u012f\u0119\u0117\u012f\u0119'

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You should look at the email.header module in the Python standard library. In particular, at the end of the documentation, there's a decode_header() function you can use to do most of the hard work for you.

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the subject line is utf8 but you're reading it as ASCII, you're safest reading it all as utf8, as ASCII is effectively only as subset of utf8.