poplib — POP3 protocol client¶Source code: Lib/poplib.py
This module defines a class, POP3, which encapsulates a connection to a
POP3 server and implements the protocol as defined in RFC 1939. The
POP3 class supports both the minimal and optional command sets from
RFC 1939. The POP3 class also supports the STLS command introduced
in RFC 2595 to enable encrypted communication on an already established connection.
Additionally, this module provides a class POP3_SSL, which provides
support for connecting to POP3 servers that use SSL as an underlying protocol
layer.
Note that POP3, though widely supported, is obsolescent. The implementation
quality of POP3 servers varies widely, and too many are quite poor. If your
mailserver supports IMAP, you would be better off using the
imaplib.IMAP4 class, as IMAP servers tend to be better implemented.
The poplib module provides two classes:
poplib.POP3(host, port=POP3_PORT[, timeout])¶This class implements the actual POP3 protocol. The connection is created when the instance is initialized. If port is omitted, the standard POP3 port (110) is used. The optional timeout parameter specifies a timeout in seconds for the connection attempt (if not specified, the global default timeout setting will be used).
poplib.POP3_SSL(host, port=POP3_SSL_PORT, keyfile=None, certfile=None, timeout=None, context=None)¶This is a subclass of POP3 that connects to the server over an SSL
encrypted socket. If port is not specified, 995, the standard POP3-over-SSL
port is used. timeout works as in the POP3 constructor.
context is an optional ssl.SSLContext object which allows
bundling SSL configuration options, certificates and private keys into a
single (potentially long-lived) structure. Please read Security considerations
for best practices.
keyfile and certfile are a legacy alternative to context - they can point to PEM-formatted private key and certificate chain files, respectively, for the SSL connection.
Changed in version 3.2: context parameter added.
Changed in version 3.4: The class now supports hostname check with
ssl.SSLContext.check_hostname and Server Name Indication (see
ssl.HAS_SNI).
Deprecated since version 3.6: keyfile and certfile are deprecated in favor of context.
Please use ssl.SSLContext.load_cert_chain() instead, or let
ssl.create_default_context() select the system’s trusted CA
certificates for you.
One exception is defined as an attribute of the poplib module:
poplib.error_proto¶Exception raised on any errors from this module (errors from socket
module are not caught). The reason for the exception is passed to the
constructor as a string.
See also
imaplibAll POP3 commands are represented by methods of the same name, in lower-case; most return the response text sent by the server.
An POP3 instance has the following methods:
POP3.set_debuglevel(level)¶Set the instance’s debugging level. This controls the amount of debugging
output printed. The default, 0, produces no debugging output. A value of
1 produces a moderate amount of debugging output, generally a single line
per request. A value of 2 or higher produces the maximum amount of
debugging output, logging each line sent and received on the control connection.
POP3.getwelcome()¶Returns the greeting string sent by the POP3 server.
POP3.capa()¶Query the server’s capabilities as specified in RFC 2449.
Returns a dictionary in the form {'name': ['param'...]}.
New in version 3.4.
POP3.user(username)¶Send user command, response should indicate that a password is required.
POP3.pass_(password)¶Send password, response includes message count and mailbox size. Note: the
mailbox on the server is locked until quit() is called.
POP3.apop(user, secret)¶Use the more secure APOP authentication to log into the POP3 server.
POP3.rpop(user)¶Use RPOP authentication (similar to UNIX r-commands) to log into POP3 server.
POP3.stat()¶Get mailbox status. The result is a tuple of 2 integers: (message count,
mailbox size).
POP3.list([which])¶Request message list, result is in the form (response, ['mesg_num octets',
...], octets). If which is set, it is the message to list.
POP3.retr(which)¶Retrieve whole message number which, and set its seen flag. Result is in form
(response, ['line', ...], octets).
POP3.dele(which)¶Flag message number which for deletion. On most servers deletions are not actually performed until QUIT (the major exception is Eudora QPOP, which deliberately violates the RFCs by doing pending deletes on any disconnect).
POP3.rset()¶Remove any deletion marks for the mailbox.
POP3.noop()¶Do nothing. Might be used as a keep-alive.
POP3.quit()¶Signoff: commit changes, unlock mailbox, drop connection.
POP3.top(which, howmuch)¶Retrieves the message header plus howmuch lines of the message after the
header of message number which. Result is in form (response, ['line', ...],
octets).
The POP3 TOP command this method uses, unlike the RETR command, doesn’t set the message’s seen flag; unfortunately, TOP is poorly specified in the RFCs and is frequently broken in off-brand servers. Test this method by hand against the POP3 servers you will use before trusting it.
POP3.uidl(which=None)¶Return message digest (unique id) list. If which is specified, result contains
the unique id for that message in the form 'response mesgnum uid, otherwise
result is list (response, ['mesgnum uid', ...], octets).
POP3.utf8()¶Try to switch to UTF-8 mode. Returns the server response if successful,
raises error_proto if not. Specified in RFC 6856.
New in version 3.5.
POP3.stls(context=None)¶Start a TLS session on the active connection as specified in RFC 2595. This is only allowed before user authentication
context parameter is a ssl.SSLContext object which allows
bundling SSL configuration options, certificates and private keys into
a single (potentially long-lived) structure. Please read Security considerations
for best practices.
This method supports hostname checking via
ssl.SSLContext.check_hostname and Server Name Indication (see
ssl.HAS_SNI).
New in version 3.4.
Instances of POP3_SSL have no additional methods. The interface of this
subclass is identical to its parent.
Here is a minimal example (without error checking) that opens a mailbox and retrieves and prints all messages:
import getpass, poplib
M = poplib.POP3('localhost')
M.user(getpass.getuser())
M.pass_(getpass.getpass())
numMessages = len(M.list()[1])
for i in range(numMessages):
for j in M.retr(i+1)[1]:
print(j)
At the end of the module, there is a test section that contains a more extensive example of usage.