"""Support for aliases(5) configuration files
API Stability: Unstable
@author: U{Jp Calderone<exarkun@twistedmatrix.com>}
TODO: Monitor files for reparsing
Handle non-local alias targets
Handle maildir alias targets
"""
import os
import tempfile
from twisted.protocols import smtp
from twisted.internet import protocol
from twisted.internet import defer
from twisted.internet import error
from twisted.python import components
from twisted.python import failure
from twisted.python import log
def handle(result, line, filename, lineNo):
parts = [p.strip() for p in line.split(':', 1)]
if len(parts) != 2:
fmt = "Invalid format on line %d of alias file %s."
arg = (lineNo, filename)
log.err(fmt % arg)
else:
user, alias = parts
result.setdefault(user.strip(), []).extend(map(str.strip, alias.split(',')))
def loadAliasFile(domains, filename=None, fp=None):
"""Load a file containing email aliases.
Lines in the file should be formatted like so:
username: alias1,alias2,...,aliasN
Aliases beginning with a | will be treated as programs, will be run, and
the message will be written to their stdin.
Aliases without a host part will be assumed to be addresses on localhost.
If a username is specified multiple times, the aliases for each are joined
together as if they had all been on one line.
@type domains: C{dict} of implementor of C{IDomain}
@param domains: The domains to which these aliases will belong.
@type filename: C{str}
@param filename: The filename from which to load aliases.
@type fp: Any file-like object.
@param fp: If specified, overrides C{filename}, and aliases are read from
it.
@rtype: C{dict}
@return: A dictionary mapping usernames to C{AliasGroup} objects.
"""
result = {}
if fp is None:
fp = file(filename)
else:
filename = getattr(fp, 'name', '<unknown>')
i = 0
prev = ''
for line in fp:
i += 1
line = line.rstrip()
if line.lstrip().startswith('#'):
continue
elif line.startswith(' ') or line.startswith('\t'):
prev = prev + line
else:
if prev:
handle(result, prev, filename, i)
prev = line
if prev:
handle(result, prev, filename, i)
for (u, a) in result.items():
addr = smtp.Address(u)
result[u] = AliasGroup(a, domains, u)
return result
class IAlias(components.Interface):
def createMessageReceiver(self):
pass
class AliasBase:
def __init__(self, domains, original):
self.domains = domains
self.original = smtp.Address(original)
def domain(self):
return self.domains[self.original.domain]
def resolve(self, aliasmap, memo=None):
if memo is None:
memo = {}
if str(self) in memo:
return None
memo[str(self)] = None
return self.createMessageReceiver()
class AddressAlias(AliasBase):
"""The simplest alias, translating one email address into another."""
__implements__ = (IAlias,)
def __init__(self, alias, *args):
AliasBase.__init__(self, *args)
self.alias = smtp.Address(alias)
def __str__(self):
return '<Address %s>' % (self.alias,)
def createMessageReceiver(self):
return self.domain().startMessage(str(self.alias))
def resolve(self, aliasmap, memo=None):
if memo is None:
memo = {}
if str(self) in memo:
return None
memo[str(self)] = None
try:
return self.domain().exists(smtp.User(self.alias, None, None, None), memo)()
except smtp.SMTPBadRcpt:
pass
if self.alias.local in aliasmap:
return aliasmap[self.alias.local].resolve(aliasmap, memo)
return None
class FileWrapper:
__implements__ = (smtp.IMessage,)
def __init__(self, filename):
self.fp = tempfile.TemporaryFile()
self.finalname = filename
def lineReceived(self, line):
self.fp.write(line + '\n')
def eomReceived(self):
self.fp.seek(0, 0)
try:
f = file(self.finalname, 'a')
except:
return defer.fail(failure.Failure())
f.write(self.fp.read())
self.fp.close()
f.close()
return defer.succeed(self.finalname)
def connectionLost(self):
self.fp.close()
self.fp = None
def __str__(self):
return '<FileWrapper %s>' % (self.finalname,)
class FileAlias(AliasBase):
__implements__ = (IAlias,)
def __init__(self, filename, *args):
AliasBase.__init__(self, *args)
self.filename = filename
def __str__(self):
return '<File %s>' % (self.filename,)
def createMessageReceiver(self):
return FileWrapper(self.filename)
class MessageWrapper:
__implements__ = (smtp.IMessage,)
done = False
def __init__(self, protocol, process=None):
self.processName = process
self.protocol = protocol
self.completion = defer.Deferred()
self.protocol.onEnd = self.completion
self.completion.addCallback(self._processEnded)
def _processEnded(self, result, err=0):
self.done = True
if err:
raise result.value
def lineReceived(self, line):
if self.done:
return
self.protocol.transport.write(line + '\n')
def eomReceived(self):
if not self.done:
self.protocol.transport.loseConnection()
self.completion.setTimeout(60)
return self.completion
def connectionLost(self):
pass
def __str__(self):
return '<ProcessWrapper %s>' % (self.processName,)
class ProcessAliasProtocol(protocol.ProcessProtocol):
def processEnded(self, reason):
if reason.check(error.ProcessDone):
self.onEnd.callback("Complete")
else:
self.onEnd.errback(reason)
class ProcessAlias(AliasBase):
"""An alias for a program."""
__implements__ = (IAlias,)
def __init__(self, path, *args):
AliasBase.__init__(self, *args)
self.path = path.split()
self.program = self.path[0]
def __str__(self):
return '<Process %s>' % (self.path,)
def createMessageReceiver(self):
from twisted.internet import reactor
p = ProcessAliasProtocol()
m = MessageWrapper(p, self.program)
fd = reactor.spawnProcess(p, self.program, self.path)
return m
class MultiWrapper:
"""Wrapper to deliver a single message to multiple recipients"""
__implements__ = (smtp.IMessage,)
def __init__(self, objs):
self.objs = objs
def lineReceived(self, line):
for o in self.objs:
o.lineReceived(line)
def eomReceived(self):
return defer.DeferredList([
o.eomReceived() for o in self.objs
])
def connectionLost(self):
for o in self.objs:
o.connectionLost()
def __str__(self):
return '<GroupWrapper %r>' % (map(str, self.objs),)
class AliasGroup(AliasBase):
"""An alias which points to more than one recipient"""
__implements__ = (IAlias,)
def __init__(self, items, *args):
AliasBase.__init__(self, *args)
self.aliases = []
while items:
addr = items.pop().strip()
if addr.startswith(':'):
try:
f = file(addr[1:])
except:
log.err("Invalid filename in alias file %r" % (addr[1:],))
else:
addr = ' '.join([l.strip() for l in f])
items.extend(addr.split(','))
elif addr.startswith('|'):
self.aliases.append(ProcessAlias(addr[1:], *args))
elif addr.startswith('/'):
if os.path.isdir(addr):
log.err("Directory delivery not supported")
else:
self.aliases.append(FileAlias(addr, *args))
else:
self.aliases.append(AddressAlias(addr, *args))
def __len__(self):
return len(self.aliases)
def __str__(self):
return '<AliasGroup [%s]>' % (', '.join(map(str, self.aliases)))
def createMessageReceiver(self):
return MultiWrapper([a.createMessageReceiver() for a in self.aliases])
def resolve(self, aliasmap, memo=None):
if memo is None:
memo = {}
r = []
for a in self.aliases:
r.append(a.resolve(aliasmap, memo))
return MultiWrapper(filter(None, r))