1 files changed, 47 insertions, 0 deletions
diff --git a/Mailman/rules/loop.py b/Mailman/rules/loop.py
new file mode 100644
index 000000000..77cedb0a6
--- /dev/null
+++ b/Mailman/rules/loop.py
@@ -0,0 +1,47 @@
+# Copyright (C) 2007 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.
+
+"""Look for a posting loop."""
+
+__all__ = ['loop_rule']
+__metaclass__ = type
+
+
+from zope.interface import implements
+
+from Mailman.i18n import _
+from Mailman.interfaces import IRule
+
+
+
+class Loop:
+    """Look for a posting loop."""
+    implements(IRule)
+
+    name = 'loop'
+    description = _("""Look for a posting loop, via the X-BeenThere header.""")
+
+    def check(self, mlist, msg, msgdata):
+        """See `IRule`."""
+        # Has this message already been posted to this list?
+        been_theres = [value.strip().lower()
+                       for value in msg.get_all('x-beenthere', [])]
+        return mlist.posting_address in been_theres
+
+
+
+loop_rule = Loop()