1 files changed, 151 insertions, 0 deletions
diff --git a/mailman/chains/headers.py b/mailman/chains/headers.py
new file mode 100644
index 000000000..cda1ea959
--- /dev/null
+++ b/mailman/chains/headers.py
@@ -0,0 +1,151 @@
+# Copyright (C) 2007-2008 by the Free Software Foundation, Inc.
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+# USA.
+
+"""The header-matching chain."""
+
+__all__ = ['HeaderMatchChain']
+__metaclass__ = type
+
+
+import re
+import logging
+import itertools
+
+from zope.interface import implements
+
+from mailman.interfaces import IChainIterator, IRule, LinkAction
+from mailman.chains.base import Chain, Link
+from mailman.i18n import _
+from mailman.configuration import config
+
+
+log = logging.getLogger('mailman.vette')
+
+
+
+def make_link(entry):
+    """Create a Link object.
+
+    :param entry: a 2- or 3-tuple describing a link.  If a 2-tuple, it is a
+        header and a pattern, and a default chain of 'hold' will be used.  If
+        a 3-tuple, the third item is the chain name to use.
+    :return: an ILink.
+    """
+    if len(entry) == 2:
+        header, pattern = entry
+        chain_name = 'hold'
+    elif len(entry) == 3:
+        header, pattern, chain_name = entry
+        # We don't assert that the chain exists here because the jump
+        # chain may not yet have been created.
+    else:
+        raise AssertionError('Bad link description: %s' % entry)
+    rule = HeaderMatchRule(header, pattern)
+    chain = config.chains[chain_name]
+    return Link(rule, LinkAction.jump, chain)
+
+
+
+class HeaderMatchRule:
+    """Header matching rule used by header-match chain."""
+    implements(IRule)
+
+    # Sequential rule counter.
+    _count = 1
+
+    def __init__(self, header, pattern):
+        self._header = header
+        self._pattern = pattern
+        self.name = 'header-match-%002d' % HeaderMatchRule._count
+        HeaderMatchRule._count += 1
+        self.description = u'%s: %s' % (header, pattern)
+        # XXX I think we should do better here, somehow recording that a
+        # particular header matched a particular pattern, but that gets ugly
+        # with RFC 2822 headers.  It also doesn't match well with the rule
+        # name concept.  For now, we just record the rather useless numeric
+        # rule name.  I suppose we could do the better hit recording in the
+        # check() method, and set self.record = False.
+        self.record = True
+
+    def check(self, mlist, msg, msgdata):
+        """See `IRule`."""
+        for value in msg.get_all(self._header, []):
+            if re.search(self._pattern, value, re.IGNORECASE):
+                return True
+        return False
+
+
+
+class HeaderMatchChain(Chain):
+    """Default header matching chain.
+
+    This could be extended by header match rules in the database.
+    """
+
+    def __init__(self):
+        super(HeaderMatchChain, self).__init__(
+            'header-match', _('The built-in header matching chain'))
+        # The header match rules are not global, so don't register them.
+        # These are the only rules that the header match chain can execute.
+        self._links = []
+        # Initialize header check rules with those from the global
+        # HEADER_MATCHES variable.
+        for entry in config.HEADER_MATCHES:
+            self._links.append(make_link(entry))
+        # Keep track of how many global header matching rules we've seen.
+        # This is so the flush() method will only delete those that were added
+        # via extend() or append_link().
+        self._permanent_link_count = len(self._links)
+
+    def extend(self, header, pattern, chain_name='hold'):
+        """Extend the existing header matches.
+
+        :param header: The case-insensitive header field name.
+        :param pattern: The pattern to match the header's value again.  The
+            match is not anchored and is done case-insensitively.
+        :param chain: Option chain to jump to if the pattern matches any of
+            the named header values.  If not given, the 'hold' chain is used.
+        """
+        self._links.append(make_link((header, pattern, chain_name)))
+
+    def flush(self):
+        """See `IMutableChain`."""
+        del self._links[self._permanent_link_count:]
+
+    def get_links(self, mlist, msg, msgdata):
+        """See `IChain`."""
+        list_iterator = HeaderMatchIterator(mlist)
+        return itertools.chain(iter(self._links), iter(list_iterator))
+
+    def __iter__(self):
+        for link in self._links:
+            yield link
+
+
+
+class HeaderMatchIterator:
+    """An iterator of both the global and list-specific chain links."""
+
+    implements(IChainIterator)
+
+    def __init__(self, mlist):
+        self._mlist = mlist
+
+    def __iter__(self):
+        """See `IChainIterator`."""
+        for entry in self._mlist.header_matches:
+            yield make_link(entry)