-This module offers several classes to implement SMTP servers. One is a generic
+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.
SMTPServer Objects
------------------
inherits from :class:`asyncore.dispatcher`, and so will insert itself into
:mod:`asyncore`'s event loop on instantiation.
-
.. method:: process_message(peer, mailfrom, rcpttos, data)
Raise :exc:`NotImplementedError` exception. Override this in subclasses to
containing the contents of the e-mail (which should be in :rfc:`2822`
format).
+ .. attribute:: channel_class
+
+ Override this in subclasses to use a custom :class:`SMTPChannel` for
+ managing SMTP clients.
+
DebuggingServer Objects
-----------------------
running this has a good chance to make you into an open relay, so please be
careful.
+SMTPChannel Objects
+-------------------
+
+.. class:: SMTPChannel(server, conn, addr)
+
+ Create a new :class:`SMTPChannel` object which manages the communication
+ between the server and a single SMTP client.
+
+ To use a custom SMTPChannel implementation you need to override the
+ :attr:`SMTPServer.channel_class` of your :class:`SMTPServer`.
+
+ 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
+ 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
+ ``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`.
+ NOOP Takes no action.
+ QUIT Closes the connection cleanly.
+ MAIL Accepts the "MAIL FROM:" syntax and stores the supplied address as
+ :attr:`mailfrom`.
+ 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.
+ ======== ===================================================================
\ No newline at end of file
import socket
import asyncore
import asynchat
+from warnings import warn
__all__ = ["SMTPServer","DebuggingServer","PureProxy","MailmanProxy"]
def __init__(self, server, conn, addr):
asynchat.async_chat.__init__(self, conn)
- self.__server = server
- self.__conn = conn
- self.__addr = addr
- self.__line = []
- self.__state = self.COMMAND
- self.__greeting = 0
- self.__mailfrom = None
- self.__rcpttos = []
- self.__data = ''
- self.__fqdn = socket.getfqdn()
- self.__peer = conn.getpeername()
- print('Peer:', repr(self.__peer), file=DEBUGSTREAM)
- self.push('220 %s %s' % (self.__fqdn, __version__))
+ self.smtp_server = server
+ self.conn = conn
+ self.addr = addr
+ self.received_lines = []
+ self.smtp_state = self.COMMAND
+ self.seen_greeting = ''
+ self.mailfrom = None
+ self.rcpttos = []
+ self.received_data = ''
+ self.fqdn = socket.getfqdn()
+ self.peer = conn.getpeername()
+ print('Peer:', repr(self.peer), file=DEBUGSTREAM)
+ self.push('220 %s %s' % (self.fqdn, __version__))
self.set_terminator(b'\r\n')
+ # properties for backwards-compatibility
+ @property
+ def __server(self):
+ warn("Access to __server attribute on SMTPChannel is deprecated, "
+ "use 'smtp_server' instead", PendingDeprecationWarning, 2)
+ return self.smtp_server
+ @__server.setter
+ def __server(self, value):
+ warn("Setting __server attribute on SMTPChannel is deprecated, "
+ "set 'smtp_server' instead", PendingDeprecationWarning, 2)
+ self.smtp_server = value
+
+ @property
+ def __line(self):
+ warn("Access to __line attribute on SMTPChannel is deprecated, "
+ "use 'received_lines' instead", PendingDeprecationWarning, 2)
+ return self.received_lines
+ @__line.setter
+ def __line(self, value):
+ warn("Setting __line attribute on SMTPChannel is deprecated, "
+ "set 'received_lines' instead", PendingDeprecationWarning, 2)
+ self.received_lines = value
+
+ @property
+ def __state(self):
+ warn("Access to __state attribute on SMTPChannel is deprecated, "
+ "use 'smtp_state' instead", PendingDeprecationWarning, 2)
+ return self.smtp_state
+ @__state.setter
+ def __state(self, value):
+ warn("Setting __state attribute on SMTPChannel is deprecated, "
+ "set 'smtp_state' instead", PendingDeprecationWarning, 2)
+ self.smtp_state = value
+
+ @property
+ def __greeting(self):
+ warn("Access to __greeting attribute on SMTPChannel is deprecated, "
+ "use 'seen_greeting' instead", PendingDeprecationWarning, 2)
+ return self.seen_greeting
+ @__greeting.setter
+ def __greeting(self, value):
+ warn("Setting __greeting attribute on SMTPChannel is deprecated, "
+ "set 'seen_greeting' instead", PendingDeprecationWarning, 2)
+ self.seen_greeting = value
+
+ @property
+ def __mailfrom(self):
+ warn("Access to __mailfrom attribute on SMTPChannel is deprecated, "
+ "use 'mailfrom' instead", PendingDeprecationWarning, 2)
+ return self.mailfrom
+ @__mailfrom.setter
+ def __mailfrom(self, value):
+ warn("Setting __mailfrom attribute on SMTPChannel is deprecated, "
+ "set 'mailfrom' instead", PendingDeprecationWarning, 2)
+ self.mailfrom = value
+
+ @property
+ def __rcpttos(self):
+ warn("Access to __rcpttos attribute on SMTPChannel is deprecated, "
+ "use 'rcpttos' instead", PendingDeprecationWarning, 2)
+ return self.rcpttos
+ @__rcpttos.setter
+ def __rcpttos(self, value):
+ warn("Setting __rcpttos attribute on SMTPChannel is deprecated, "
+ "set 'rcpttos' instead", PendingDeprecationWarning, 2)
+ self.rcpttos = value
+
+ @property
+ def __data(self):
+ warn("Access to __data attribute on SMTPChannel is deprecated, "
+ "use 'received_data' instead", PendingDeprecationWarning, 2)
+ return self.received_data
+ @__data.setter
+ def __data(self, value):
+ warn("Setting __data attribute on SMTPChannel is deprecated, "
+ "set 'received_data' instead", PendingDeprecationWarning, 2)
+ self.received_data = value
+
+ @property
+ def __fqdn(self):
+ warn("Access to __fqdn attribute on SMTPChannel is deprecated, "
+ "use 'fqdn' instead", PendingDeprecationWarning, 2)
+ return self.fqdn
+ @__fqdn.setter
+ def __fqdn(self, value):
+ warn("Setting __fqdn attribute on SMTPChannel is deprecated, "
+ "set 'fqdn' instead", PendingDeprecationWarning, 2)
+ self.fqdn = value
+
+ @property
+ def __peer(self):
+ warn("Access to __peer attribute on SMTPChannel is deprecated, "
+ "use 'peer' instead", PendingDeprecationWarning, 2)
+ return self.peer
+ @__peer.setter
+ def __peer(self, value):
+ warn("Setting __peer attribute on SMTPChannel is deprecated, "
+ "set 'peer' instead", PendingDeprecationWarning, 2)
+ self.peer = value
+
+ @property
+ def __conn(self):
+ warn("Access to __conn attribute on SMTPChannel is deprecated, "
+ "use 'conn' instead", PendingDeprecationWarning, 2)
+ return self.conn
+ @__conn.setter
+ def __conn(self, value):
+ warn("Setting __conn attribute on SMTPChannel is deprecated, "
+ "set 'conn' instead", PendingDeprecationWarning, 2)
+ self.conn = value
+
+ @property
+ def __addr(self):
+ warn("Access to __addr attribute on SMTPChannel is deprecated, "
+ "use 'addr' instead", PendingDeprecationWarning, 2)
+ return self.addr
+ @__addr.setter
+ def __addr(self, value):
+ warn("Setting __addr attribute on SMTPChannel is deprecated, "
+ "set 'addr' instead", PendingDeprecationWarning, 2)
+ self.addr = value
+
# Overrides base class for convenience
def push(self, msg):
asynchat.async_chat.push(self, bytes(msg + '\r\n', 'ascii'))
# Implementation of base class abstract method
def collect_incoming_data(self, data):
- self.__line.append(str(data, "utf8"))
+ self.received_lines.append(str(data, "utf8"))
# Implementation of base class abstract method
def found_terminator(self):
- line = EMPTYSTRING.join(self.__line)
+ line = EMPTYSTRING.join(self.received_lines)
print('Data:', repr(line), file=DEBUGSTREAM)
- self.__line = []
- if self.__state == self.COMMAND:
+ self.received_lines = []
+ if self.smtp_state == self.COMMAND:
if not line:
self.push('500 Error: bad syntax')
return
method(arg)
return
else:
- if self.__state != self.DATA:
+ if self.smtp_state != self.DATA:
self.push('451 Internal confusion')
return
# Remove extraneous carriage returns and de-transparency according
data.append(text[1:])
else:
data.append(text)
- self.__data = NEWLINE.join(data)
- status = self.__server.process_message(self.__peer,
- self.__mailfrom,
- self.__rcpttos,
- self.__data)
- self.__rcpttos = []
- self.__mailfrom = None
- self.__state = self.COMMAND
+ self.received_data = NEWLINE.join(data)
+ status = self.__server.process_message(self.peer,
+ self.mailfrom,
+ self.rcpttos,
+ self.received_data)
+ self.rcpttos = []
+ self.mailfrom = None
+ self.smtp_state = self.COMMAND
self.set_terminator(b'\r\n')
if not status:
self.push('250 Ok')
if not arg:
self.push('501 Syntax: HELO hostname')
return
- if self.__greeting:
+ if self.seen_greeting:
self.push('503 Duplicate HELO/EHLO')
else:
- self.__greeting = arg
- self.push('250 %s' % self.__fqdn)
+ self.seen_greeting = arg
+ self.push('250 %s' % self.fqdn)
def smtp_NOOP(self, arg):
if arg:
if not address:
self.push('501 Syntax: MAIL FROM:<address>')
return
- if self.__mailfrom:
+ if self.mailfrom:
self.push('503 Error: nested MAIL command')
return
- self.__mailfrom = address
- print('sender:', self.__mailfrom, file=DEBUGSTREAM)
+ self.mailfrom = address
+ print('sender:', self.mailfrom, file=DEBUGSTREAM)
self.push('250 Ok')
def smtp_RCPT(self, arg):
print('===> RCPT', arg, file=DEBUGSTREAM)
- if not self.__mailfrom:
+ if not self.mailfrom:
self.push('503 Error: need MAIL command')
return
address = self.__getaddr('TO:', arg) if arg else None
if not address:
self.push('501 Syntax: RCPT TO: <address>')
return
- self.__rcpttos.append(address)
- print('recips:', self.__rcpttos, file=DEBUGSTREAM)
+ self.rcpttos.append(address)
+ print('recips:', self.rcpttos, file=DEBUGSTREAM)
self.push('250 Ok')
def smtp_RSET(self, arg):
self.push('501 Syntax: RSET')
return
# Resets the sender, recipients, and data, but not the greeting
- self.__mailfrom = None
- self.__rcpttos = []
- self.__data = ''
- self.__state = self.COMMAND
+ self.mailfrom = None
+ self.rcpttos = []
+ self.received_data = ''
+ self.smtp_state = self.COMMAND
self.push('250 Ok')
def smtp_DATA(self, arg):
- if not self.__rcpttos:
+ if not self.rcpttos:
self.push('503 Error: need RCPT command')
return
if arg:
self.push('501 Syntax: DATA')
return
- self.__state = self.DATA
+ self.smtp_state = self.DATA
self.set_terminator(b'\r\n.\r\n')
self.push('354 End data with <CR><LF>.<CR><LF>')
\f
class SMTPServer(asyncore.dispatcher):
+ # SMTPChannel class to use for managing client connections
+ channel_class = SMTPChannel
+
def __init__(self, localaddr, remoteaddr):
self._localaddr = localaddr
self._remoteaddr = remoteaddr
def handle_accept(self):
conn, addr = self.accept()
print('Incoming connection from %s' % repr(addr), file=DEBUGSTREAM)
- channel = SMTPChannel(self, conn, addr)
+ channel = self.channel_class(self, conn, addr)
# API for "doing something useful with the message"
def process_message(self, peer, mailfrom, rcpttos, data):
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