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      1 :mod:`poplib` --- POP3 protocol client
      2 ======================================
      3 
      4 .. module:: poplib
      5    :synopsis: POP3 protocol client (requires sockets).
      6 .. sectionauthor:: Andrew T. Csillag
      7 .. revised by ESR, January 2000
      8 
      9 .. index:: pair: POP3; protocol
     10 
     11 **Source code:** :source:`Lib/poplib.py`
     12 
     13 --------------
     14 
     15 This module defines a class, :class:`POP3`, which encapsulates a connection to a
     16 POP3 server and implements the protocol as defined in :rfc:`1725`.  The
     17 :class:`POP3` class supports both the minimal and optional command sets.
     18 Additionally, this module provides a class :class:`POP3_SSL`, which provides
     19 support for connecting to POP3 servers that use SSL as an underlying protocol
     20 layer.
     21 
     22 Note that POP3, though widely supported, is obsolescent.  The implementation
     23 quality of POP3 servers varies widely, and too many are quite poor. If your
     24 mailserver supports IMAP, you would be better off using the
     25 :class:`imaplib.IMAP4` class, as IMAP servers tend to be better implemented.
     26 
     27 The :mod:`poplib` module provides two classes:
     28 
     29 
     30 .. class:: POP3(host[, port[, timeout]])
     31 
     32    This class implements the actual POP3 protocol.  The connection is created when
     33    the instance is initialized. If *port* is omitted, the standard POP3 port (110)
     34    is used. The optional *timeout* parameter specifies a timeout in seconds for the
     35    connection attempt (if not specified, the global default timeout setting will
     36    be used).
     37 
     38    .. versionchanged:: 2.6
     39       *timeout* was added.
     40 
     41 
     42 .. class:: POP3_SSL(host[, port[, keyfile[, certfile]]])
     43 
     44    This is a subclass of :class:`POP3` that connects to the server over an SSL
     45    encrypted socket.  If *port* is not specified, 995, the standard POP3-over-SSL
     46    port is used.  *keyfile* and *certfile* are also optional - they can contain a
     47    PEM formatted private key and certificate chain file for the SSL connection.
     48 
     49    .. versionadded:: 2.4
     50 
     51 One exception is defined as an attribute of the :mod:`poplib` module:
     52 
     53 
     54 .. exception:: error_proto
     55 
     56    Exception raised on any errors from this module (errors from :mod:`socket`
     57    module are not caught). The reason for the exception is passed to the
     58    constructor as a string.
     59 
     60 
     61 .. seealso::
     62 
     63    Module :mod:`imaplib`
     64       The standard Python IMAP module.
     65 
     66    `Frequently Asked Questions About Fetchmail <http://www.catb.org/~esr/fetchmail/fetchmail-FAQ.html>`_
     67       The FAQ for the :program:`fetchmail` POP/IMAP client collects information on
     68       POP3 server variations and RFC noncompliance that may be useful if you need to
     69       write an application based on the POP protocol.
     70 
     71 
     72 .. _pop3-objects:
     73 
     74 POP3 Objects
     75 ------------
     76 
     77 All POP3 commands are represented by methods of the same name, in lower-case;
     78 most return the response text sent by the server.
     79 
     80 An :class:`POP3` instance has the following methods:
     81 
     82 
     83 .. method:: POP3.set_debuglevel(level)
     84 
     85    Set the instance's debugging level.  This controls the amount of debugging
     86    output printed.  The default, ``0``, produces no debugging output.  A value of
     87    ``1`` produces a moderate amount of debugging output, generally a single line
     88    per request.  A value of ``2`` or higher produces the maximum amount of
     89    debugging output, logging each line sent and received on the control connection.
     90 
     91 
     92 .. method:: POP3.getwelcome()
     93 
     94    Returns the greeting string sent by the POP3 server.
     95 
     96 
     97 .. method:: POP3.user(username)
     98 
     99    Send user command, response should indicate that a password is required.
    100 
    101 
    102 .. method:: POP3.pass_(password)
    103 
    104    Send password, response includes message count and mailbox size. Note: the
    105    mailbox on the server is locked until :meth:`~poplib.quit` is called.
    106 
    107 
    108 .. method:: POP3.apop(user, secret)
    109 
    110    Use the more secure APOP authentication to log into the POP3 server.
    111 
    112 
    113 .. method:: POP3.rpop(user)
    114 
    115    Use RPOP authentication (similar to UNIX r-commands) to log into POP3 server.
    116 
    117 
    118 .. method:: POP3.stat()
    119 
    120    Get mailbox status.  The result is a tuple of 2 integers: ``(message count,
    121    mailbox size)``.
    122 
    123 
    124 .. method:: POP3.list([which])
    125 
    126    Request message list, result is in the form ``(response, ['mesg_num octets',
    127    ...], octets)``. If *which* is set, it is the message to list.
    128 
    129 
    130 .. method:: POP3.retr(which)
    131 
    132    Retrieve whole message number *which*, and set its seen flag. Result is in form
    133    ``(response, ['line', ...], octets)``.
    134 
    135 
    136 .. method:: POP3.dele(which)
    137 
    138    Flag message number *which* for deletion.  On most servers deletions are not
    139    actually performed until QUIT (the major exception is Eudora QPOP, which
    140    deliberately violates the RFCs by doing pending deletes on any disconnect).
    141 
    142 
    143 .. method:: POP3.rset()
    144 
    145    Remove any deletion marks for the mailbox.
    146 
    147 
    148 .. method:: POP3.noop()
    149 
    150    Do nothing.  Might be used as a keep-alive.
    151 
    152 
    153 .. method:: POP3.quit()
    154 
    155    Signoff:  commit changes, unlock mailbox, drop connection.
    156 
    157 
    158 .. method:: POP3.top(which, howmuch)
    159 
    160    Retrieves the message header plus *howmuch* lines of the message after the
    161    header of message number *which*. Result is in form ``(response, ['line', ...],
    162    octets)``.
    163 
    164    The POP3 TOP command this method uses, unlike the RETR command, doesn't set the
    165    message's seen flag; unfortunately, TOP is poorly specified in the RFCs and is
    166    frequently broken in off-brand servers. Test this method by hand against the
    167    POP3 servers you will use before trusting it.
    168 
    169 
    170 .. method:: POP3.uidl([which])
    171 
    172    Return message digest (unique id) list. If *which* is specified, result contains
    173    the unique id for that message in the form ``'response mesgnum uid``, otherwise
    174    result is list ``(response, ['mesgnum uid', ...], octets)``.
    175 
    176 Instances of :class:`POP3_SSL` have no additional methods. The interface of this
    177 subclass is identical to its parent.
    178 
    179 
    180 .. _pop3-example:
    181 
    182 POP3 Example
    183 ------------
    184 
    185 Here is a minimal example (without error checking) that opens a mailbox and
    186 retrieves and prints all messages::
    187 
    188    import getpass, poplib
    189 
    190    M = poplib.POP3('localhost')
    191    M.user(getpass.getuser())
    192    M.pass_(getpass.getpass())
    193    numMessages = len(M.list()[1])
    194    for i in range(numMessages):
    195        for j in M.retr(i+1)[1]:
    196            print j
    197 
    198 At the end of the module, there is a test section that contains a more extensive
    199 example of usage.
    200 
    201