VirtualMailManager/catchall.py
branchv0.6.x
changeset 504 f180ead60568
child 507 2aae58cddfa9
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/VirtualMailManager/catchall.py	Mon Apr 09 18:10:56 2012 +0200
@@ -0,0 +1,171 @@
+# -*- coding: UTF-8 -*-
+# Copyright (c) 2012 martin f. krafft
+# See COPYING for distribution information.
+"""
+    VirtualMailManager.catchall
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+    Virtual Mail Manager's CatchallAlias class to manage domain catch-all
+    aliases.
+
+    This is heavily based on (more or less a copy of) the Alias class, because
+    fundamentally, catchall aliases are aliases, but without a localpart.
+    While Alias could potentially derive from CatchallAlias to reuse some of
+    the functionality, it's probably not worth it. I found no sensible way to
+    derive CatchallAlias from Alias, or at least none that would harness the
+    powers of polymorphism.
+
+    Yet, we reuse the AliasError exception class, which makes sense.
+"""
+
+from VirtualMailManager.domain import get_gid
+from VirtualMailManager.emailaddress import \
+     EmailAddress, DestinationEmailAddress as DestAddr
+from VirtualMailManager.errors import AliasError as AErr
+from VirtualMailManager.ext.postconf import Postconf
+from VirtualMailManager.pycompat import all
+from VirtualMailManager.constants import \
+     ALIAS_EXCEEDS_EXPANSION_LIMIT, NO_SUCH_ALIAS, NO_SUCH_DOMAIN
+
+
+_ = lambda msg: msg
+cfg_dget = lambda option: None
+
+
+class CatchallAlias(object):
+    """Class to manage domain catch-all aliases."""
+    __slots__ = ('_domain', '_dests', '_gid', '_dbh')
+
+    def __init__(self, dbh, domain):
+        self._domain = domain
+        self._dbh = dbh
+        self._gid = get_gid(self._dbh, self._addr.domain)
+        if not self._gid:
+            raise AErr(_(u"The domain '%s' does not exist.") %
+                       self._addr.domainname, NO_SUCH_DOMAIN)
+        self._dests = []
+
+        self._load_dests()
+
+    def _load_dests(self):
+        """Loads all known destination addresses into the _dests list."""
+        dbc = self._dbh.cursor()
+        dbc.execute('SELECT destination FROM catchall WHERE gid = %s',
+                    self._gid)
+        dests = dbc.fetchall()
+        if dbc.rowcount > 0:
+            self._dests.extend(DestAddr(dest[0], self._dbh) for dest in dests)
+        dbc.close()
+
+    def _check_expansion(self, count_new):
+        """Checks the current expansion limit of the alias."""
+        postconf = Postconf(cfg_dget('bin.postconf'))
+        limit = long(postconf.read('virtual_alias_expansion_limit'))
+        dcount = len(self._dests)
+        failed = False
+        if dcount == limit or dcount + count_new > limit:
+            failed = True
+            errmsg = _(
+u"""Cannot add %(count_new)i new destination(s) to catchall alias for
+domain '%(domain)s'. Currently this alias expands into %(count)i/%(limit)i
+recipients. %(count_new)i additional destination(s) will render this alias
+unusable.
+Hint: Increase Postfix' virtual_alias_expansion_limit""")
+        elif dcount > limit:
+            failed = True
+            errmsg = _(
+u"""Cannot add %(count_new)i new destination(s) to catchall alias for
+domain '%(domain)s'. This alias already exceeds its expansion limit (%(count)i/%(limit)i).
+So its unusable, all messages addressed to this alias will be bounced.
+Hint: Delete some destination addresses.""")
+        if failed:
+            raise AErr(errmsg % {'domain': self._domain, 'count': dcount,
+                                 'limit': limit, 'count_new': count_new},
+                       ALIAS_EXCEEDS_EXPANSION_LIMIT)
+
+    def _delete(self, destination=None):
+        """Deletes a destination from the catchall alias, if ``destination``
+        is not ``None``.  If ``destination`` is None, the catchall alias with
+        all its destination addresses will be deleted.
+
+        """
+        dbc = self._dbh.cursor()
+        if not destination:
+            dbc.execute('DELETE FROM catchall WHERE gid = %s', self._gid)
+        else:
+            dbc.execute('DELETE FROM catchall WHERE gid = %s '
+                        'AND destination = %s', (self._gid, str(destination)))
+        if dbc.rowcount > 0:
+            self._dbh.commit()
+        dbc.close()
+
+    def __len__(self):
+        """Returns the number of destinations of the catchall alias."""
+        return len(self._dests)
+
+    @property
+    def domain(self):
+        """The Alias' domain."""
+        return self._domain
+
+    def add_destinations(self, destinations, warnings=None):
+        """Adds the `EmailAddress`es from *destinations* list to the
+        destinations of the catchall alias.
+
+        Destinations, that are already assigned to the alias, will be
+        removed from *destinations*.  When done, this method will return
+        a set with all destinations, that were saved in the database.
+        """
+        destinations = set(destinations)
+        assert destinations and \
+                all(isinstance(dest, EmailAddress) for dest in destinations)
+        if not warnings is None:
+            assert isinstance(warnings, list)
+        duplicates = destinations.intersection(set(self._dests))
+        if duplicates:
+            destinations.difference_update(set(self._dests))
+            if not warnings is None:
+                warnings.extend(duplicates)
+        if not destinations:
+            return destinations
+        self._check_expansion(len(destinations))
+        dbc = self._dbh.cursor()
+        dbc.executemany("INSERT INTO catchall (gid, destination) "
+                        "VALUES (%d, %%s)" % self._gid,
+                        ((str(destination),) for destination in destinations))
+        self._dbh.commit()
+        dbc.close()
+        self._dests.extend(destinations)
+        return destinations
+
+    def del_destination(self, destination):
+        """Deletes the specified ``destination`` address from the catchall
+        alias."""
+        assert isinstance(destination, EmailAddress)
+        if not self._dests:
+            raise AErr(_(u"There are no catchall aliases defined for "
+                         u"domain '%s'.") % self._domain, NO_SUCH_ALIAS)
+        if not destination in self._dests:
+            raise AErr(_(u"The address '%(addr)s' is not a destination of "
+                         u"the catchall alias for domain '%(domain)s'.")
+                       % {'addr': destination, 'domain': self._domain},
+                       NO_SUCH_ALIAS)
+        self._delete(destination)
+        self._dests.remove(destination)
+
+    def get_destinations(self):
+        """Returns an iterator for all destinations of the catchall alias."""
+        if not self._dests:
+            raise AErr(_(u"There are no catchall aliases defined for "
+                         u"domain '%s'.") % self._domain, NO_SUCH_ALIAS)
+        return iter(self._dests)
+
+    def delete(self):
+        """Deletes all catchall destinations for the domain."""
+        if not self._dests:
+            raise AErr(_(u"There are no catchall aliases defined for "
+                         u"domain '%s'.") % self._domain, NO_SUCH_ALIAS)
+        self._delete()
+        del self._dests[:]
+
+del _, cfg_dget