Erle Robotics Python Networking Gitbook Free

Summary Information

When you first select a folder, the IMAP server provides some summary information about it—about the folder itself and also about its messages. The summary is returned by IMAPClient as a dictionary. Here are the keys that most IMAP servers will return when you run select_folder():

• EXISTS: An integer giving the number of messages in the folder.

• FLAGS: A list of the flags that can be set on messages in this folder.

• RECENT: Specifies the server’s approximation of the number of messages that have appeared in the folder since the last time an IMAP client ran select_folder() on it.

• PERMANENTFLAGS: Specifies the list of custom flags that can be set on messages; this is usually empty.

• UIDNEXT: The server’s guess about the UID that will be assigned to the next incoming (or uploaded) message

• UIDVALIDITY: A string that can be used by clients to verify that the UID numbering has not changed; if you come back to a folder and this is a different value than the last time you connected, then the UID number has started over and your stored UID values are no longer valid.

• UNSEEN: Specifies the message number of the first unseen message (one without the \Seen flag) in the folder.

Of these flags, servers are only required to return FLAGS, EXISTS, and RECENT, though most will include at least UIDVALIDITY as well.

folder_info.pyshows an example program that reads and displays the summary information of my INBOX mail folder:

import getpass, sys
from imapclient import IMAPClient

try:
    hostname, username = sys.argv[1:]
except ValueError:
    print 'usage: %s hostname username' % sys.argv[0]
    sys.exit(2)

c = IMAPClient(hostname, ssl=True)
try:
    c.login(username, getpass.getpass())
except c.Error, e:
    print 'Could not log in:', e
    sys.exit(1)
else:
    select_dict = c.select_folder('INBOX', readonly=True)
    for k, v in select_dict.items():
        print '%s: %r' % (k, v)
    c.logout()

When run, this program displays results such as this:

```

root@erlerobot:~/Python_files# python folder_info.py imap.example.com [email protected] Password: EXISTS: 3 PERMANENTFLAGS: ('\Answered', '\Flagged', '\Draft', '\Deleted', '\Seen', '\*') READ-WRITE: True UIDNEXT: 2626 FLAGS: ('\Answered', '\Flagged', '\Draft', '\Deleted', '\Seen') UIDVALIDITY: 1 RECENT: 0

```

That shows that my INBOX folder contains three messages, none of which have arrived since I last checked. If your program is interested in using UIDs that it stored during previous sessions, remember to compare the UIDVALIDITY to a stored value from a previous session.