IMAPClient - How to get subject and sender?

I'm trying to make a simple program to check and show unread messages, but I have problem while trying to get subject and sender adress. For sender I've tried this method:

import email
m = server.fetch([a], ['RFC822']) 
#a is variable with email id
msg = email.message_from_string(m[a], ['RFC822'])
print msg['from']
from email.utils import parseaddr
print parseaddr(msg['from'])

But it didn't work. I was getting this error:

Traceback (most recent call last):
File "C:/Users/ExampleUser/AppData/Local/Programs/Python/Python35-32/myprogram.py", line 20, in <module>
msg = email.message_from_string(m[a], ['RFC822'])
File "C:\Users\ExampleUser\AppData\Local\Programs\Python\Python35-32\lib\email\__init__.py", line 38, in message_from_string
return Parser(*args, **kws).parsestr(s)
File "C:\Users\ExampleUser\AppData\Local\Programs\Python\Python35-32\lib\email\parser.py", line 68, in parsestr
return self.parse(StringIO(text), headersonly=headersonly)
TypeError: initial_value must be str or None, not dict

I also used this:

print(server.fetch([a], ['BODY[HEADER.FIELDS (FROM)]']))

but the result was like:

defaultdict(<class 'dict'>, {410: {b'BODY[HEADER.FIELDS ("FROM")]': b'From: "=?utf-8?q?senderexample?=" <[email protected]>\r\n\r\n', b'SEQ': 357}, 357: {b'SEQ': 357, b'FLAGS': (b'\\Seen',)}})

Is there a way to repair the first method, or make the result of second look like:

Sender Example <[email protected]>

? And I also don't know how to get email subject. But I guess it's the same as sender, but with other arguments. So the only thing I need are these arguments.

Solution

You should start by reviewing various IMAP libraries which are available for Python and use one which fits your needs. There are multiple ways of fetching the data you need in IMAP (the protocol), and by extension also in Python (and its libraries).

For example, the most straightforward way of getting the data you need in IMAP the protocol is through fetching the ENVELOPE object. You will still have to perform decoding of RFC2047 encoding of the non-ASCII data (that's that =?utf-8?q?... bit that you're seeing), but at least it would save you from parsing RFC5322 header structure with multiple decades of compatibility syntax rules.