Let’s put together what we’ve learned about fetching, sending, parsing, and composing email in a simple but functional command-line console email tool. The script in Example 14-20 implements an interactive email session—users may type commands to read, send, and delete email messages.
Example 14-20. PP3EInternetEmailpymail.py
#!/usr/local/bin/python
##########################################################################
# pymail - a simple console email interface client in Python; uses Python
# POP3 mail interface module to view POP email account messages; uses
# email package modules to extract mail message headers (not rfc822);
##########################################################################
import poplib, smtplib, email.Utils
from email.Parser import Parser
from email.Message import Message
def inputmessage( ):
import sys
From = raw_input('From? ').strip( )
To = raw_input('To? ').strip( ) # datetime hdr set auto
To = To.split(';')
Subj = raw_input('Subj? ').strip( )
print 'Type message text, end with line="."'
text = ''
while True:
line = sys.stdin.readline( )
if line == '.
': break
text += line
return From, To, Subj, text
def sendmessage( ):
From, To, Subj, text = inputmessage( )
msg = Message( )
msg['From'] = From
msg['To'] = ';'.join(To)
msg['Subject'] = Subj
msg['Date'] = email.Utils.formatdate( ) # curr datetime, rfc2822
msg.set_payload(text)
server = smtplib.SMTP(mailconfig.smtpservername)
try:
failed = server.sendmail(From, To, str(msg)) # may also raise exc
except:
print 'Error - send failed'
else:
if failed: print 'Failed:', failed
def connect(servername, user, passwd):
print 'Connecting...'
server = poplib.POP3(servername)
server.user(user) # connect, log in to mail server
server.pass_(passwd) # pass is a reserved word
print server.getwelcome( ) # print returned greeting message
return server
def loadmessages(servername, user, passwd, loadfrom=1):
server = connect(servername, user, passwd)
try: print server.list( )
(msgCount, msgBytes) = server.stat( )
print 'There are', msgCount, 'mail messages in', msgBytes, 'bytes'
print 'Retrieving:',
msgList = []
for i in range(loadfrom, msgCount+1): # empty if low >= high
print i, # fetch mail now
(hdr, message, octets) = server.retr(i) # save text on list
msgList.append('
'.join(message)) # leave mail on server
print
finally:
server.quit( ) # unlock the mail box
assert len(msgList) == (msgCount - loadfrom) + 1 # msg nums start at 1
return msgList
def deletemessages(servername, user, passwd, toDelete, verify=1):
print 'To be deleted:', toDelete
if verify and raw_input('Delete?')[:1] not in ['y', 'Y']:
print 'Delete cancelled.'
else:
server = connect(servername, user, passwd)
try:
print 'Deleting messages from server.'
for msgnum in toDelete: # reconnect to delete mail
server.dele(msgnum) # mbox locked until quit( )
finally:
server.quit( )
def showindex(msgList):
count = 0 # show some mail headers
for msgtext in msgList:
msghdrs = Parser( ).parsestr(msgtext, headersonly=True)
count = count + 1
print '%d: %d bytes' % (count, len(msgtext))
for hdr in ('From', 'Date', 'Subject'):
try:
print ' %s=>%s' % (hdr, msghdrs[hdr])
except KeyError:
print ' %s=>(unknown)' % hdr
#print '
%s=>%s' % (hdr, msghdrs.get(hdr, '(unknown)')
if count % 5 == 0:
raw_input('[Press Enter key]') # pause after each 5
def showmessage(i, msgList):
if 1 <= i <= len(msgList):
print '-'*80
msg = Parser( ).parsestr(msgList[i-1])
print msg.get_payload( ) # prints payload: string, or [Messages]
#print msgList[i-1] # old: prints entire mail--hdrs+text
print '-'*80 # to get text only, call file.read( )
else: # after rfc822.Message reads hdr lines
print 'Bad message number'
def savemessage(i, mailfile, msgList):
if 1 <= i <= len(msgList):
open(mailfile, 'a').write('
' + msgList[i-1] + '-'*80 + '
')
else:
print 'Bad message number'
def msgnum(command):
try:
return int(command.split( )[1])
except:
return -1 # assume this is bad
helptext = """
Available commands:
i - index display
l n? - list all messages (or just message n)
d n? - mark all messages for deletion (or just message n)
s n? - save all messages to a file (or just message n)
m - compose and send a new mail message
q - quit pymail
? - display this help text
"""
def interact(msgList, mailfile):
showindex(msgList)
toDelete = []
while 1:
try:
command = raw_input('[Pymail] Action? (i, l, d, s, m, q, ?) ')
except EOFError:
command = 'q'
# quit
if not command or command == 'q':
break
# index
elif command[0] == 'i':
showindex(msgList)
# list
elif command[0] == 'l':
if len(command) == 1:
for i in range(1, len(msgList)+1):
showmessage(i, msgList)
else:
showmessage(msgnum(command), msgList)
# save
elif command[0] == 's':
if len(command) == 1:
for i in range(1, len(msgList)+1):
savemessage(i, mailfile, msgList)
else:
savemessage(msgnum(command), mailfile, msgList)
# delete
elif command[0] == 'd':
if len(command) == 1:
toDelete = range(1, len(msgList)+1) # delete all later
else:
delnum = msgnum(command)
if (1 <= delnum <= len(msgList)) and (delnum not in toDelete):
toDelete.append(delnum)
else:
print 'Bad message number'
# mail
elif command[0] == 'm': # send a new mail via SMTP
sendmessage( )
#execfile('smtpmail.py', {}) # alt: run file in own namespace
elif command[0] == '?':
print helptext
else:
print 'What? -- type "?" for commands help'
return toDelete
if _ _name_ _ == '_ _main_ _':
import getpass, mailconfig
mailserver = mailconfig.popservername # ex: 'starship.python.net'
mailuser = mailconfig.popusername # ex: 'lutz'
mailfile = mailconfig.savemailfile # ex: r'c:stuffsavemail'
mailpswd = getpass.getpass('Password for %s?' % mailserver)
print '[Pymail email client]'
msgList = loadmessages(mailserver, mailuser, mailpswd) # load all
toDelete = interact(msgList, mailfile)
if toDelete: deletemessages(mailserver, mailuser, mailpswd, toDelete)
print 'Bye.'There isn’t much new here—just a combination of user-interface logic and tools we’ve already met, plus a handful of new techniques:
- Loads
This client loads all email from the server into an in-memory Python list only once, on startup; you must exit and restart to reload newly arrived email.
- Saves
On demand,
pymailsaves the raw text of a selected message into a local file, whose name you place in themailconfigmodule.- Deletions
We finally support on-request deletion of mail from the server here: in
pymail, mails are selected for deletion by number, but are still only physically removed from your server on exit, and then only if you verify the operation. By deleting only on exit, we avoid changing mail message numbers during a session—under POP, deleting a mail not at the end of the list decrements the number assigned to all mails following the one deleted. Since mail is cached in memory bypymail, future operations on the numbered messages in memory may be applied to the wrong mail if deletions were done immediately.[*]- Parsing and composing messages
pymailnow displays just the payload of a message on listing commands, not the entire raw text, and the mail index listing only displays selected headers parsed out of each message. Python’semailpackage is used to extract headers and content from a message, as shown in the prior section. Similarly, we useemailto compose a message and ask for its string to ship as a mail.
By now, I expect that you know enough Python to read this script
for a deeper look, so instead of saying more about its design here,
let’s jump into an interactive pymail session to see how it works.
Let’s start up pymail to read and delete email at our
mail server and send new messages. pymail runs on any machine with Python and
sockets, fetches mail from any email server with a POP interface on
which you have an account, and sends mail via the SMTP server you’ve
named in the mailconfig
module.
Here it is in action running on my Windows laptop machine; its
operation is identical on other machines. First, we start the
script, supply a POP password (remember, SMTP servers require no
password), and wait for the pymail email list index to appear; as is,
this version loads the full text of all mails in the inbox on
startup:
C:...PP3EInternetEmail>python pymail.pyPassword for pop.earthlink.net? [Pymail email client] Connecting... +OK NGPopper vEL_6_10 at earthlink.net ready <[email protected]... ('+OK', ['1 876', '2 800', '3 818', '4 770', '5 819'], 35) There are 5 mail messages in 4083 bytes Retrieving: 1 2 3 4 5 1: 1019 bytes From=>[email protected] Date=>Wed, 08 Feb 2006 05:23:13 -0000 Subject=>I'm a Lumberjack, and I'm Okay 2: 883 bytes From=>[email protected] Date=>Wed, 08 Feb 2006 05:24:06 -0000 Subject=>testing 3: 967 bytes From=>[email protected] Date=>Tue Feb 07 22:51:08 2006 Subject=>A B C D E F G 4: 854 bytes From=>[email protected] Date=>Tue Feb 07 23:19:51 2006 Subject=>testing smtpmail 5: 968 bytes From=>[email protected] Date=>Tue Feb 07 23:34:23 2006 Subject=>a b c d e f g [Press Enter key] [Pymail] Action? (i, l, d, s, m, q, ?)l 5-------------------------------------------------------------------------------- Spam; Spam and eggs; Spam, spam, and spam -------------------------------------------------------------------------------- [Pymail] Action? (i, l, d, s, m, q, ?)l 3-------------------------------------------------------------------------------- Fiddle de dum, Fiddle de dee, Eric the half a bee. -------------------------------------------------------------------------------- [Pymail] Action? (i, l, d, s, m, q, ?)
Once pymail downloads your
email to a Python list on the local client machine, you type command
letters to process it. The l
command lists (prints) the contents of a given mail number; here, we
used it to list the two emails we wrote with the smtpmail script in the preceding
section.
pymail also lets us get
command help, delete messages (deletions actually occur at the
server on exit from the program), and save messages away in a local
text file whose name is listed in the mailconfig module we saw earlier:
[Pymail] Action? (i, l, d, s, m, q, ?)?Available commands: i - index display l n? - list all messages (or just message n) d n? - mark all messages for deletion (or just message n) s n? - save all messages to a file (or just message n) m - compose and send a new mail message q - quit pymail ? - display this help text [Pymail] Action? (i, l, d, s, m, q, ?)d 1[Pymail] Action? (i, l, d, s, m, q, ?)s 4
Now, let’s pick the m mail
compose option—pymail inputs the
mail parts, builds mail text with email, and ships it off with smtplib. Because the mail is sent by SMTP,
you can use arbitrary “From” addresses here; but again, you
generally shouldn’t do that (unless, of course, you’re trying to
come up with interesting examples for a book):
[Pymail] Action? (i, l, d, s, m, q, ?)mFrom?[email protected]To?[email protected]Subj?Among our weapons are these:Type message text, end with line="."Nobody Expects the Spanish Inquisition!.[Pymail] Action? (i, l, d, s, m, q, ?)qTo be deleted: [1] Delete?yConnecting... +OK NGPopper vEL_6_10 at earthlink.net ready <[email protected]... Deleting messages from server. Bye.
As mentioned, deletions really happen only on exit. When we
quit pymail with the q command, it tells us which messages are
queued for deletion, and verifies the request. Once verified,
pymail finally contacts the mail
server again and issues POP calls to delete the selected mail
messages. Because deletions change message numbers in the server’s
inbox, postponing deletion until exit simplifies the handling of
already loaded email.
Because pymail downloads
mail from your server into a local Python list only once at startup,
though, we need to start pymail
again to refetch mail from the server if we want to see the result
of the mail we sent and the deletion we made. Here, our new mail
shows up as number 5, and the original mail assigned number 1 is
gone:
C:...PP3EInternetEmail>pymail.pyPassword for pop.earthlink.net? [Pymail email client] Connecting... +OK NGPopper vEL_6_10 at earthlink.net ready <[email protected]... ('+OK', ['1 800', '2 818', '3 770', '4 819', '5 841'], 35) There are 5 mail messages in 4048 bytes Retrieving: 1 2 3 4 5 1: 883 bytes From=>[email protected] Date=>Wed, 08 Feb 2006 05:24:06 -0000 Subject=>testing 2: 967 bytes From=>[email protected] Date=>Tue Feb 07 22:51:08 2006 Subject=>A B C D E F G 3: 854 bytes From=>[email protected] Date=>Tue Feb 07 23:19:51 2006 Subject=>testing smtpmail 4: 968 bytes From=>[email protected] Date=>Tue Feb 07 23:34:23 2006 Subject=>a b c d e f g 5: 989 bytes From=>[email protected] Date=>Wed, 08 Feb 2006 08:58:27 -0000 Subject=>Among our weapons are these: [Press Enter key] [Pymail] Action? (i, l, d, s, m, q, ?)l 5-------------------------------------------------------------------------------- Nobody Expects the Spanish Inquisition! -------------------------------------------------------------------------------- [Pymail] Action? (i, l, d, s, m, q, ?)qBye.
Finally, if you are running this live, you will also find the
mail save file on your machine, containing the one message we asked
to be saved in the prior session; it’s simply the raw text of saved
emails, with separator lines. This is both human and
machine-readable—in principle, another script could load saved mail
from this file into a Python list by calling the string object’s
split method on the file’s text
with the separator line as a delimiter.
[*] There will be more on POP message numbers when we
study mailtools later in
this chapter. Interestingly, the list of message numbers to
be deleted need not be sorted; they remain valid for the
duration of the delete connection, so deletions earlier in
the list don’t change numbers of messages later in the list
while you are still connected to the POP server. We’ll also
see that some subtle issues may arise if mails in the server
inbox are deleted without pymail’s knowledge (e.g., by your
ISP or another email client); although very rare, suffice it to
say for now that deletions in this script are not guaranteed
to be accurate.