diff options
| -rw-r--r-- | Doc/library/smtpd.rst | 100 | ||||
| -rwxr-xr-x | Lib/smtpd.py | 210 |
2 files changed, 266 insertions, 44 deletions
diff --git a/Doc/library/smtpd.rst b/Doc/library/smtpd.rst index 276751634d..df67de9433 100644 --- a/Doc/library/smtpd.rst +++ b/Doc/library/smtpd.rst @@ -10,10 +10,14 @@ -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 ------------------ @@ -26,7 +30,6 @@ 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 @@ -37,6 +40,11 @@ SMTPServer Objects 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 ----------------------- @@ -71,3 +79,91 @@ MailmanProxy 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 diff --git a/Lib/smtpd.py b/Lib/smtpd.py index d7c5c93814..dd8398836f 100755 --- a/Lib/smtpd.py +++ b/Lib/smtpd.py @@ -78,6 +78,7 @@ import time import socket import asyncore import asynchat +from warnings import warn __all__ = ["SMTPServer","DebuggingServer","PureProxy","MailmanProxy"] @@ -111,35 +112,157 @@ class SMTPChannel(asynchat.async_chat): 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 @@ -158,7 +281,7 @@ class SMTPChannel(asynchat.async_chat): 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 @@ -169,14 +292,14 @@ class SMTPChannel(asynchat.async_chat): 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') @@ -188,11 +311,11 @@ class SMTPChannel(asynchat.async_chat): 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: @@ -225,24 +348,24 @@ class SMTPChannel(asynchat.async_chat): 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): @@ -250,26 +373,29 @@ class SMTPChannel(asynchat.async_chat): 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>') 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 @@ -291,7 +417,7 @@ class SMTPServer(asyncore.dispatcher): 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): |