Erle Robotics Python Networking Gitbook Free


Fortunately, a popular and battle-tested IMAP library for Python does exist, and is available for easy installation from the Python Package Index. The IMAPClient package is written by a friendly Python programmer named Menno Smits, and in fact uses the Standard Library Once installed, you can use the python interpreter in the virtual environment to run the program shown in

import getpass, sys
from imapclient import IMAPClient

    hostname, username = sys.argv[1:]
except ValueError:
    print 'usage: %s hostname username' % sys.argv[0]

c = IMAPClient(hostname, ssl=True)
    c.login(username, getpass.getpass())
except c.Error, e:
    print 'Could not log in:', e

print 'Capabilities:', c.capabilities()
print 'Listing mailboxes:'
data = c.list_folders()
for flags, delimiter, folder_name in data:
    print '  %-30s%s %s' % (' '.join(flags), delimiter, folder_name)

You can see immediately from the code that more details of the protocol exchange are now being handled on our behalf. For example, we no longer get a status code back that we have to check every time we run a command; instead, the library is doing that check for us and will raise an exception to stop us in our tracks if anything goes wrong. Second, you can see that each result from the LIST command—which in this library is offered as the list_folders() method instead of the list() method offered by imaplib—has already been parsed into Python data types for us. Each line of data comes back as a tuple giving us the folder flags, folder name delimiter, and folder name, and the flags themselves are a sequence of strings. Take a look at the code below,for what the output of this second script looks like:

Listing mailboxes:
\HasNoChildren / INBOX
\HasNoChildren / Personal
\HasNoChildren / Receipts
\HasNoChildren / Travel
\HasNoChildren / Work
\Noselect \HasChildren / [Gmail]
\HasChildren \HasNoChildren / [Gmail]/All Mail
\HasNoChildren / [Gmail]/Drafts
\HasChildren \HasNoChildren / [Gmail]/Sent Mail
\HasNoChildren / [Gmail]/Spam
\HasNoChildren / [Gmail]/Starred
\HasChildren \HasNoChildren / [Gmail]/Trash

The standard flags listed for each folder may be zero or more of the following:

  • \Noinferiors: This means that the folder does not contain any sub-folders and that it is not possible for it to contain sub-folders in the future. Your IMAP client will receive an error if it tries to create a sub-folder under this folder.
  • \Noselect: This means that it is not possible to run select_folder() on this folder—that is, this folder does not and cannot contain any messages. (Perhaps it exists just to allow sub-folders beneath it, as one possibility.)
  • \Marked: This means that the server considers this box to be interesting in some way; generally, this indicates that new messages have been delivered since the last time the folder was selected. However, the absence of \Marked does not guarantee that the folder does not contain new messages; some servers simply do not implement \Marked at all.
  • \Unmarked: This guarantees that the folder doesn’t contain new messages.