mirror of https://github.com/python/cpython
251 lines
9.6 KiB
ReStructuredText
251 lines
9.6 KiB
ReStructuredText
:mod:`smtpd` --- SMTP Server
|
|
============================
|
|
|
|
.. module:: smtpd
|
|
:synopsis: A SMTP server implementation in Python.
|
|
|
|
.. moduleauthor:: Barry Warsaw <barry@python.org>
|
|
.. sectionauthor:: Moshe Zadka <moshez@moshez.org>
|
|
|
|
**Source code:** :source:`Lib/smtpd.py`
|
|
|
|
--------------
|
|
|
|
This module offers several classes to implement SMTP (email) servers.
|
|
|
|
Several server implementations are present; one is a generic
|
|
do-nothing implementation, which can be overridden, while the other two offer
|
|
specific mail-sending strategies.
|
|
|
|
Additionally the SMTPChannel may be extended to implement very specific
|
|
interaction behaviour with SMTP clients.
|
|
|
|
The code supports :RFC:`5321`, plus the :rfc:`1870` SIZE and :rfc:`6531`
|
|
SMTPUTF8 extensions.
|
|
|
|
|
|
SMTPServer Objects
|
|
------------------
|
|
|
|
|
|
.. class:: SMTPServer(localaddr, remoteaddr, data_size_limit=33554432,\
|
|
map=None, enable_SMTPUTF8=False, decode_data=True)
|
|
|
|
Create a new :class:`SMTPServer` object, which binds to local address
|
|
*localaddr*. It will treat *remoteaddr* as an upstream SMTP relayer. It
|
|
inherits from :class:`asyncore.dispatcher`, and so will insert itself into
|
|
:mod:`asyncore`'s event loop on instantiation.
|
|
|
|
*data_size_limit* specifies the maximum number of bytes that will be
|
|
accepted in a ``DATA`` command. A value of ``None`` or ``0`` means no
|
|
limit.
|
|
|
|
*enable_SMTPUTF8* determins whether the ``SMTPUTF8`` extension (as defined
|
|
in :RFC:`6531`) should be enabled. The default is ``False``. If
|
|
*enable_SMTPUTF* is set to ``True``, the :meth:`process_smtputf8_message`
|
|
method must be defined. A :exc:`ValueError` is raised if both
|
|
*enable_SMTPUTF8* and *decode_data* are set to ``True`` at the same time.
|
|
|
|
A dictionary can be specified in *map* to avoid using a global socket map.
|
|
|
|
*decode_data* specifies whether the data portion of the SMTP transaction
|
|
should be decoded using UTF-8. The default is ``True`` for backward
|
|
compatibility reasons, but will change to ``False`` in Python 3.6. Specify
|
|
the keyword value explicitly to avoid the :exc:`DeprecationWarning`.
|
|
|
|
.. method:: process_message(peer, mailfrom, rcpttos, data)
|
|
|
|
Raise a :exc:`NotImplementedError` exception. Override this in subclasses to
|
|
do something useful with this message. Whatever was passed in the
|
|
constructor as *remoteaddr* will be available as the :attr:`_remoteaddr`
|
|
attribute. *peer* is the remote host's address, *mailfrom* is the envelope
|
|
originator, *rcpttos* are the envelope recipients and *data* is a string
|
|
containing the contents of the e-mail (which should be in :rfc:`5321`
|
|
format).
|
|
|
|
If the *decode_data* constructor keyword is set to ``True``, the *data*
|
|
argument will be a unicode string. If it is set to ``False``, it
|
|
will be a bytes object.
|
|
|
|
Return ``None`` to request a normal ``250 Ok`` response; otherwise
|
|
return the desired response string in :RFC:`5321` format.
|
|
|
|
.. method:: process_smtputf8_message(peer, mailfrom, rcpttos, data)
|
|
|
|
Raise a :exc:`NotImplementedError` exception. Override this in
|
|
subclasses to do something useful with messages when *enable_SMTPUTF8*
|
|
has been set to ``True`` and the SMTP client requested ``SMTPUTF8``,
|
|
since this method is called rather than :meth:`process_message` when the
|
|
client actively requests ``SMTPUTF8``. The *data* argument will always
|
|
be a bytes object, and any non-``None`` return value should conform to
|
|
:rfc:`6531`; otherwise, the API is the same as for
|
|
:meth:`process_message`.
|
|
|
|
.. attribute:: channel_class
|
|
|
|
Override this in subclasses to use a custom :class:`SMTPChannel` for
|
|
managing SMTP clients.
|
|
|
|
.. versionchanged:: 3.4
|
|
The *map* argument was added.
|
|
|
|
.. versionchanged:: 3.5
|
|
*localaddr* and *remoteaddr* may now contain IPv6 addresses.
|
|
|
|
.. versionadded:: 3.5
|
|
the *decode_data* and *enable_SMTPUTF8* constructor arguments, and the
|
|
:meth:`process_smtputf8_message` method.
|
|
|
|
|
|
DebuggingServer Objects
|
|
-----------------------
|
|
|
|
|
|
.. class:: DebuggingServer(localaddr, remoteaddr)
|
|
|
|
Create a new debugging server. Arguments are as per :class:`SMTPServer`.
|
|
Messages will be discarded, and printed on stdout.
|
|
|
|
|
|
PureProxy Objects
|
|
-----------------
|
|
|
|
|
|
.. class:: PureProxy(localaddr, remoteaddr)
|
|
|
|
Create a new pure proxy server. Arguments are as per :class:`SMTPServer`.
|
|
Everything will be relayed to *remoteaddr*. Note that running this has a good
|
|
chance to make you into an open relay, so please be careful.
|
|
|
|
|
|
MailmanProxy Objects
|
|
--------------------
|
|
|
|
|
|
.. class:: MailmanProxy(localaddr, remoteaddr)
|
|
|
|
Create a new pure proxy server. Arguments are as per :class:`SMTPServer`.
|
|
Everything will be relayed to *remoteaddr*, unless local mailman configurations
|
|
knows about an address, in which case it will be handled via mailman. Note that
|
|
running this has a good chance to make you into an open relay, so please be
|
|
careful.
|
|
|
|
SMTPChannel Objects
|
|
-------------------
|
|
|
|
.. class:: SMTPChannel(server, conn, addr, data_size_limit=33554432,\
|
|
map=None, enable_SMTPUTF8=False, decode_data=True)
|
|
|
|
Create a new :class:`SMTPChannel` object which manages the communication
|
|
between the server and a single SMTP client.
|
|
|
|
*conn* and *addr* are as per the instance variables described below.
|
|
|
|
*data_size_limit* specifies the maximum number of bytes that will be
|
|
accepted in a ``DATA`` command. A value of ``None`` or ``0`` means no
|
|
limit.
|
|
|
|
*enable_SMTPUTF8* determins whether the ``SMTPUTF8`` extension (as defined
|
|
in :RFC:`6531`) should be enabled. The default is ``False``. A
|
|
:exc:`ValueError` is raised if both *enable_SMTPUTF8* and *decode_data* are
|
|
set to ``True`` at the same time.
|
|
|
|
A dictionary can be specified in *map* to avoid using a global socket map.
|
|
|
|
*decode_data* specifies whether the data portion of the SMTP transaction
|
|
should be decoded using UTF-8. The default is ``True`` for backward
|
|
compatibility reasons, but will change to ``False`` in Python 3.6. Specify
|
|
the keyword value explicitly to avoid the :exc:`DeprecationWarning`.
|
|
|
|
To use a custom SMTPChannel implementation you need to override the
|
|
:attr:`SMTPServer.channel_class` of your :class:`SMTPServer`.
|
|
|
|
.. versionchanged:: 3.5
|
|
the *decode_data* and *enable_SMTPUTF8* arguments were added.
|
|
|
|
The :class:`SMTPChannel` has the following instance variables:
|
|
|
|
.. attribute:: smtp_server
|
|
|
|
Holds the :class:`SMTPServer` that spawned this channel.
|
|
|
|
.. attribute:: conn
|
|
|
|
Holds the socket object connecting to the client.
|
|
|
|
.. attribute:: addr
|
|
|
|
Holds the address of the client, the second value returned by
|
|
:func:`socket.accept <socket.socket.accept>`
|
|
|
|
.. attribute:: received_lines
|
|
|
|
Holds a list of the line strings (decoded using UTF-8) received from
|
|
the client. The lines have their ``"\r\n"`` line ending translated to
|
|
``"\n"``.
|
|
|
|
.. attribute:: smtp_state
|
|
|
|
Holds the current state of the channel. This will be either
|
|
:attr:`COMMAND` initially and then :attr:`DATA` after the client sends
|
|
a "DATA" line.
|
|
|
|
.. attribute:: seen_greeting
|
|
|
|
Holds a string containing the greeting sent by the client in its "HELO".
|
|
|
|
.. attribute:: mailfrom
|
|
|
|
Holds a string containing the address identified in the "MAIL FROM:" line
|
|
from the client.
|
|
|
|
.. attribute:: rcpttos
|
|
|
|
Holds a list of strings containing the addresses identified in the
|
|
"RCPT TO:" lines from the client.
|
|
|
|
.. attribute:: received_data
|
|
|
|
Holds a string containing all of the data sent by the client during the
|
|
DATA state, up to but not including the terminating ``"\r\n.\r\n"``.
|
|
|
|
.. attribute:: fqdn
|
|
|
|
Holds the fully-qualified domain name of the server as returned by
|
|
:func:`socket.getfqdn`.
|
|
|
|
.. attribute:: peer
|
|
|
|
Holds the name of the client peer as returned by ``conn.getpeername()``
|
|
where ``conn`` is :attr:`conn`.
|
|
|
|
The :class:`SMTPChannel` operates by invoking methods named ``smtp_<command>``
|
|
upon reception of a command line from the client. Built into the base
|
|
:class:`SMTPChannel` class are methods for handling the following commands
|
|
(and responding to them appropriately):
|
|
|
|
======== ===================================================================
|
|
Command Action taken
|
|
======== ===================================================================
|
|
HELO Accepts the greeting from the client and stores it in
|
|
:attr:`seen_greeting`. Sets server to base command mode.
|
|
EHLO Accepts the greeting from the client and stores it in
|
|
:attr:`seen_greeting`. Sets server to extended command mode.
|
|
NOOP Takes no action.
|
|
QUIT Closes the connection cleanly.
|
|
MAIL Accepts the "MAIL FROM:" syntax and stores the supplied address as
|
|
:attr:`mailfrom`. In extended command mode, accepts the
|
|
:rfc:`1870` SIZE attribute and responds appropriately based on the
|
|
value of *data_size_limit*.
|
|
RCPT Accepts the "RCPT TO:" syntax and stores the supplied addresses in
|
|
the :attr:`rcpttos` list.
|
|
RSET Resets the :attr:`mailfrom`, :attr:`rcpttos`, and
|
|
:attr:`received_data`, but not the greeting.
|
|
DATA Sets the internal state to :attr:`DATA` and stores remaining lines
|
|
from the client in :attr:`received_data` until the terminator
|
|
``"\r\n.\r\n"`` is received.
|
|
HELP Returns minimal information on command syntax
|
|
VRFY Returns code 252 (the server doesn't know if the address is valid)
|
|
EXPN Reports that the command is not implemented.
|
|
======== ===================================================================
|