POP and IMAP - Post Office Protocol and Internet Message Access Protocol

 POP and IMAP - Post Office Protocol and Internet Message Access Protocol

 用来从 SMTP Server 上下载邮件的协议.

     POP - The Post Office Protocol
         通过 poplib 链接服务器,
         例子,
             import sys
             import poplib, email
             host = ''
             userid = 'userid'
             PW = 'PW'
             storedir = '' # email stored directory(the mailbox)
             P = poplib.POP3(host)
             try:
                 P.user(userid)
                 P.pass_(PW)
             except poplib.error_proto as e:
                 print("Login failed: ", e)
                 sys.exit()

             maillist = P.list()[1]   # the list of message in the mailbox
             print(" %d mails." % len(maillist))
             dellist = []

             for item in maillist:   # email download
                 number, octets = item.split(' ')
                 print("Start downloading mail %s (%S Bytes)" % (number, octets))
                 lines = P.retr(number)[1]  # retrieve the 'number'th email
                 msg = email.message_from_string("\n".join(lines)) #  email object
                 with open(storedir) as FH:
                     FH.write(msg.as_string(unixfrom=1) + "\n")
                 dellist.append(number)
                 print("Downloaded mail %s (%S Bytes)" % (number, octets))

             counter = 0
             for num in dellist:   # delete email
                 counter += 1
                 print("Deleting mail %d of %d" %(counter, len(dellist)))
                 P.dele(number) # delete mail

             print("%d emails were deleted from server" % counter)
             P.quit() # logout from server

     IMAP - Internet Message Access Protocol
         相比于 POP 协议  IMAP 更加完善,且功能更加强大
         例子, opens a mailbox and retrieves and prints all messages:

             import getpass, imaplib
             M = imaplib.IMAP4()
             M.login(getpass.getuser(), getpass.getpass())
             M.select()
             typ, data = M.search(None, 'ALL')
             for num in data[0].split():
                 typ, data = M.fetch(num, '(RFC822)')
                 print('Message %s\n%s\n' % (num, data[0][1]))
             M.close()
             M.logout()

 Reference,
     python doc,
         https://docs.python.org/3/library/imaplib.html