How do you extract multiple email addresses from an RFC 2822 mail header in python?

Question

Python's email module is great for parsing headers. However, the To: header can have multiple recipients, and there may be multiple To: headers. So how do I split out each of the email addresses? I can't split on the comma, since the comma can be quoted. Is there a way to do this?

Demo code:

msg="""To: user1@company1.com, "User Two" <user2@company2.com", "Three, User <user3@company3.com>                               
From: anotheruser@user.com                                                                                                      
Subject: This is a subject                                                                                                      

This is the message.                                                                                                            
"""

import email

msg822 = email.message_from_string(msg)
for to in msg822.get_all("To"):
    print("To:",to)

Current output:

$ python x.py
To: user1@company1.com, "User Two" <user2@company2.com", "Three, User <user3@company3.com>
$ 

Answer 1

Pass all of the To lines through email.utils.getaddresses():

msg="""To: user1@company1.com, John Doe <user2@example.com>, "Public, John Q." <user3@example.com>
From: anotheruser@user.com
Subject: This is a subject

This is the message.
"""

import email

msg822 = email.message_from_string(msg)
for to in email.utils.getaddresses(msg822.get_all("To", [])):
    print("To:",to)

Note that I rewrote your To line. I believe your example wasn't a valid format.

Reference: https://docs.python.org/2/library/email.util.html#email.utils.getaddresses