6 files changed, 330 insertions, 248 deletions

diff --git a/Mailman/Handlers/Approve.py b/Mailman/Handlers/Approve.py
deleted file mode 100644
index 1198e6ea7..000000000
--- a/Mailman/Handlers/Approve.py
+++ /dev/null
@@ -1,116 +0,0 @@
-# Copyright (C) 1998-2007 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.
-
-"""Determine whether the message is pre-approved for delivery."""
-
-import re
-
-from email.Iterators import typed_subpart_iterator
-
-from Mailman import Errors
-from Mailman.configuration import config
-
-EMPTYSTRING = ''
-
-
-
-def process(mlist, msg, msgdata):
-    # Short circuits
-    if msgdata.get('approved'):
-        # Digests, Usenet postings, and some other messages come pre-approved.
-        # XXX we may want to further filter Usenet messages, so the test above
-        # may not be entirely correct.
-        return
-    # See if the message has an Approved or Approve header with a valid
-    # moderator password.  Also look at the first non-whitespace line in the
-    # file to see if it looks like an Approved header.
-    missing = object()
-    password = msg.get('approved', msg.get('approve', missing))
-    if password is missing:
-        # Find the first text/plain part in the message
-        part = None
-        stripped = False
-        for part in typed_subpart_iterator(msg, 'text', 'plain'):
-            break
-        # XXX I'm not entirely sure why, but it is possible for the payload of
-        # the part to be None, and you can't splitlines() on None.
-        if part and part.get_payload() is not None:
-            lines = part.get_payload(decode=True).splitlines(True)
-            for lineno, line in enumerate(lines):
-                if line.strip():
-                    break
-            if ':' in line:
-                header, value = line.split(':', 1)
-                if header.lower() in ('approved', 'approve'):
-                    password = value.strip()
-                    # Now strip the first line from the payload so the
-                    # password doesn't leak.
-                    del lines[lineno]
-                    reset_payload(part, EMPTYSTRING.join(lines))
-                    stripped = True
-        if stripped:
-            # MAS: Bug 1181161 - Now try all the text parts in case it's
-            # multipart/alternative with the approved line in HTML or other
-            # text part.  We make a pattern from the Approved line and delete
-            # it from all text/* parts in which we find it.  It would be
-            # better to just iterate forward, but email compatability for pre
-            # Python 2.2 returns a list, not a true iterator.
-            #
-            # This will process all the multipart/alternative parts in the
-            # message as well as all other text parts.  We shouldn't find the
-            # pattern outside the multipart/alternative parts, but if we do,
-            # it is probably best to delete it anyway as it does contain the
-            # password.
-            #
-            # Make a pattern to delete.  We can't just delete a line because
-            # line of HTML or other fancy text may include additional message
-            # text.  This pattern works with HTML.  It may not work with rtf
-            # or whatever else is possible.
-            pattern = header + ':(\s| )*' + re.escape(password)
-            for part in typed_subpart_iterator(msg, 'text'):
-                if part is not None and part.get_payload() is not None:
-                    lines = part.get_payload(decode=True)
-                    if re.search(pattern, lines):
-                        reset_payload(part, re.sub(pattern, '', lines))
-    if password is not missing and password == mlist.moderator_password:
-        # BAW: should we definitely deny if the password exists but does not
-        # match?  For now we'll let it percolate up for further determination.
-        msgdata['approved'] = True
-        # Used by the Emergency module
-        msgdata['adminapproved'] = True
-    # Has this message already been posted to this list?
-    beentheres = [s.strip().lower() for s in msg.get_all('x-beenthere', [])]
-    if mlist.posting_address in beentheres:
-        raise Errors.LoopError
-
-
-def reset_payload(part, payload):
-    # Set decoded payload maintaining content-type, format and delsp.
-    # TK: Messages with 'charset=' cause trouble.  So, instead of
-    #     part.get_content_charset('us-ascii') ...
-    cset = part.get_content_charset() or 'us-ascii'
-    ctype = part.get_content_type()
-    format = part.get_param('format')
-    delsp = part.get_param('delsp')
-    del part['content-transfer-encoding']
-    del part['content-type']
-    part.set_payload(payload, cset)
-    part.set_type(ctype)
-    if format:
-        part.set_param('Format', format)
-    if delsp:
-        part.set_param('DelSp', delsp)
diff --git a/Mailman/app/rules.py b/Mailman/app/rules.py
index 152694177..37f5d9af4 100644
--- a/Mailman/app/rules.py
+++ b/Mailman/app/rules.py
@@ -17,6 +17,11 @@
 
 """Process all rules defined by entry points."""
 
+__all__ = [
+    'find_rule',
+    'process',
+    ]
+
 from Mailman.app.plugins import get_plugins
 
 
@@ -24,8 +29,7 @@ from Mailman.app.plugins import get_plugins
 def process(mlist, msg, msgdata, rule_set=None):
     """Default rule processing plugin.
 
-    Rules are processed in random order so a rule should not permanently alter
-    a message or the message metadata.
+    Rules are processed in random order.
 
     :param msg: The message object.
     :param msgdata: The message metadata.
@@ -44,3 +48,17 @@ def process(mlist, msg, msgdata, rule_set=None):
         if rule.check(mlist, msg, msgdata):
             rule_matches.add(rule.name)
     return rule_matches
+
+
+
+def find_rule(rule_name):
+    """Find the named rule.
+
+    :param rule_name: The name of the rule to find.
+    :return: The named rule, or None if no such rule exists.
+    """
+    for rule_set_class in get_plugins('mailman.rules'):
+        rule = rule_set_class().get(rule_name)
+        if rule is not None:
+            return rule
+    return None
diff --git a/Mailman/docs/approve.txt b/Mailman/docs/approve.txt
index 56afc1dd4..ea07058f8 100644
--- a/Mailman/docs/approve.txt
+++ b/Mailman/docs/approve.txt
@@ -13,98 +13,72 @@ approval queue.  This has several use cases:
 In order to support this, a mailing list can be given a 'moderator password'
 which is shared among all the administrators.
 
-    >>> from Mailman.Handlers.Approve import process
     >>> from Mailman.configuration import config
     >>> mlist = config.db.list_manager.create(u'_xtest@example.com')
+    >>> mlist.moderator_password = u'abcxyz'
+
+The 'approved' rule determines whether the message contains the proper
+approval or not.
 
+    >>> from Mailman.app.rules import find_rule
+    >>> rule = find_rule('approved')
+    >>> rule.name
+    'approved'
 
-Short circuiting
-----------------
 
-The message may have been approved by some other means, as evident in the
-message metadata.  In this case, the handler returns immediately.
+No approval
+-----------
+
+If the message has no Approve or Approved header, then the rule does not
+match.
 
     >>> msg = message_from_string(u"""\
     ... From: aperson@example.com
     ...
     ... An important message.
     ... """)
-    >>> msgdata = {'approved': True}
-    >>> process(mlist, msg, msgdata)
-    >>> print msg.as_string()
-    From: aperson@example.com
-    <BLANKLINE>
-    An important message.
-    <BLANKLINE>
-    >>> msgdata
-    {'approved': True}
+    >>> rule.check(mlist, msg, {})
+    False
 
+If the message has an Approve or Approved header with a value that does not
+match the moderator password, then the rule does not match.  However, the
+header is still removed.
 
-The Approved header
--------------------
+    >>> msg['Approve'] = u'12345'
+    >>> rule.check(mlist, msg, {})
+    False
+    >>> print msg['approve']
+    None
 
-If the moderator password is given in an Approved header, then the message
-gets sent through with no further posting moderation.  The Approved header is
-not stripped in this handler module, but instead in the Cleanse module.  This
-ensures that no moderator approval password in the headers will leak out.
+    >>> del msg['approve']
+    >>> msg['Approved'] = u'12345'
+    >>> rule.check(mlist, msg, {})
+    False
+    >>> print msg['approved']
+    None
 
-    >>> mlist.moderator_password = u'abcxyz'
-    >>> msg['Approved'] = u'abcxyz'
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
-    >>> print msg.as_string()
-    From: aperson@example.com
-    Approved: abcxyz
-    <BLANKLINE>
-    An important message.
-    <BLANKLINE>
-    >>> sorted(msgdata.items())
-    [('adminapproved', True), ('approved', True)]
+    >>> del msg['approved']
 
-But if the wrong password is given, then the message is not marked as being
-approved.  The header is still removed though.
 
-    >>> del msg['Approved']
-    >>> msg['Approved'] = u'123456'
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
-    >>> print msg.as_string()
-    From: aperson@example.com
-    Approved: 123456
-    <BLANKLINE>
-    An important message.
-    <BLANKLINE>
-    >>> msgdata
-    {}
+Using an approval header
+------------------------
 
-In the spirit of being liberal in what you accept, using an Approve header is
-completely synonymous.
+If the moderator password is given in an Approve header, then the rule
+matches, and the Approve header is stripped.
 
-    >>> del msg['Approved']
     >>> msg['Approve'] = u'abcxyz'
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
-    >>> print msg.as_string()
-    From: aperson@example.com
-    Approve: abcxyz
-    <BLANKLINE>
-    An important message.
-    <BLANKLINE>
-    >>> sorted(msgdata.items())
-    [('adminapproved', True), ('approved', True)]
+    >>> rule.check(mlist, msg, {})
+    True
+    >>> print msg['approve']
+    None
 
-    >>> del msg['Approve']
-    >>> msg['Approve'] = u'123456'
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
-    >>> print msg.as_string()
-    From: aperson@example.com
-    Approve: 123456
-    <BLANKLINE>
-    An important message.
-    <BLANKLINE>
-    >>> msgdata
-    {}
+Similarly, for the Approved header.
+
+    >>> msg['Approved'] = u'abcxyz'
+    >>> rule.check(mlist, msg, {})
+    True
+    >>> print msg['approved']
+    None
 
 
 Using a pseudo-header
@@ -113,17 +87,20 @@ Using a pseudo-header
 Different mail user agents have varying degrees to which they support custom
 headers like Approve and Approved.  For this reason, Mailman also supports
 using a 'pseudo-header', which is really just the first non-whitespace line in
-the payload of the message of the message.  If this pseudo-header looks like a
-matching Approve or Approved header, the message is similarly allowed to pass.
+the payload of the message.  If this pseudo-header looks like a matching
+Approve or Approved header, the message is similarly allowed to pass.
 
     >>> msg = message_from_string(u"""\
     ... From: aperson@example.com
     ...
-    ... Approved: abcxyz
+    ... Approve: abcxyz
     ... An important message.
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    True
+
+The pseudo-header is removed.
+
     >>> print msg.as_string()
     From: aperson@example.com
     Content-Transfer-Encoding: 7bit
@@ -132,17 +109,18 @@ matching Approve or Approved header, the message is similarly allowed to pass.
     <BLANKLINE>
     An important message.
     <BLANKLINE>
-    >>> sorted(msgdata.items())
-    [('adminapproved', True), ('approved', True)]
+
+Similarly for the Approved header.
 
     >>> msg = message_from_string(u"""\
     ... From: aperson@example.com
     ...
-    ... Approve: abcxyz
+    ... Approved: abcxyz
     ... An important message.
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    True
+
     >>> print msg.as_string()
     From: aperson@example.com
     Content-Transfer-Encoding: 7bit
@@ -151,8 +129,6 @@ matching Approve or Approved header, the message is similarly allowed to pass.
     <BLANKLINE>
     An important message.
     <BLANKLINE>
-    >>> sorted(msgdata.items())
-    [('adminapproved', True), ('approved', True)]
 
 As before, a mismatch in the pseudo-header does not approve the message, but
 the pseudo-header line is still removed.
@@ -160,11 +136,12 @@ the pseudo-header line is still removed.
     >>> msg = message_from_string(u"""\
     ... From: aperson@example.com
     ...
-    ... Approved: 123456
+    ... Approve: 123456
     ... An important message.
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    False
+
     >>> print msg.as_string()
     From: aperson@example.com
     Content-Transfer-Encoding: 7bit
@@ -173,17 +150,18 @@ the pseudo-header line is still removed.
     <BLANKLINE>
     An important message.
     <BLANKLINE>
-    >>> msgdata
-    {}
+
+Similarly for the Approved header.
 
     >>> msg = message_from_string(u"""\
     ... From: aperson@example.com
     ...
-    ... Approve: 123456
+    ... Approved: 123456
     ... An important message.
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    False
+
     >>> print msg.as_string()
     From: aperson@example.com
     Content-Transfer-Encoding: 7bit
@@ -192,8 +170,6 @@ the pseudo-header line is still removed.
     <BLANKLINE>
     An important message.
     <BLANKLINE>
-    >>> msgdata
-    {}
 
 
 MIME multipart support
@@ -211,18 +187,21 @@ used with MIME documents.
     ... --AAA
     ... Content-Type: application/x-ignore
     ...
-    ... Approved: 123456
+    ... Approve: 123456
     ... The above line will be ignored.
     ...
     ... --AAA
     ... Content-Type: text/plain
     ...
-    ... Approved: abcxyz
+    ... Approve: abcxyz
     ... An important message.
     ... --AAA--
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    True
+
+Like before, the pseudo-header is removed, but only from the text parts.
+
     >>> print msg.as_string()
     From: aperson@example.com
     MIME-Version: 1.0
@@ -231,7 +210,7 @@ used with MIME documents.
     --AAA
     Content-Type: application/x-ignore
     <BLANKLINE>
-    Approved: 123456
+    Approve: 123456
     The above line will be ignored.
     <BLANKLINE>
     --AAA
@@ -242,8 +221,8 @@ used with MIME documents.
     An important message.
     --AAA--
     <BLANKLINE>
-    >>> sorted(msgdata.items())
-    [('adminapproved', True), ('approved', True)]
+
+The same goes for the Approved message.
 
     >>> msg = message_from_string(u"""\
     ... From: aperson@example.com
@@ -253,18 +232,21 @@ used with MIME documents.
     ... --AAA
     ... Content-Type: application/x-ignore
     ...
-    ... Approve: 123456
+    ... Approved: 123456
     ... The above line will be ignored.
     ...
     ... --AAA
     ... Content-Type: text/plain
     ...
-    ... Approve: abcxyz
+    ... Approved: abcxyz
     ... An important message.
     ... --AAA--
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    True
+
+And the header is removed.
+
     >>> print msg.as_string()
     From: aperson@example.com
     MIME-Version: 1.0
@@ -273,7 +255,7 @@ used with MIME documents.
     --AAA
     Content-Type: application/x-ignore
     <BLANKLINE>
-    Approve: 123456
+    Approved: 123456
     The above line will be ignored.
     <BLANKLINE>
     --AAA
@@ -284,8 +266,6 @@ used with MIME documents.
     An important message.
     --AAA--
     <BLANKLINE>
-    >>> sorted(msgdata.items())
-    [('adminapproved', True), ('approved', True)]
 
 Here, the correct password is in the non-text/plain part, so it is ignored.
 
@@ -307,8 +287,11 @@ Here, the correct password is in the non-text/plain part, so it is ignored.
     ... An important message.
     ... --AAA--
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    False
+
+And yet the pseudo-header is still stripped.
+
     >>> print msg.as_string()
     From: aperson@example.com
     MIME-Version: 1.0
@@ -327,8 +310,8 @@ Here, the correct password is in the non-text/plain part, so it is ignored.
     <BLANKLINE>
     An important message.
     --AAA--
-    >>> msgdata
-    {}
+
+As before, the same goes for the Approved header.
 
     >>> msg = message_from_string(u"""\
     ... From: aperson@example.com
@@ -338,18 +321,21 @@ Here, the correct password is in the non-text/plain part, so it is ignored.
     ... --AAA
     ... Content-Type: application/x-ignore
     ...
-    ... Approve: abcxyz
+    ... Approved: abcxyz
     ... The above line will be ignored.
     ...
     ... --AAA
     ... Content-Type: text/plain
     ...
-    ... Approve: 123456
+    ... Approved: 123456
     ... An important message.
     ... --AAA--
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    False
+
+And the pseudo-header is removed.
+
     >>> print msg.as_string()
     From: aperson@example.com
     MIME-Version: 1.0
@@ -358,7 +344,7 @@ Here, the correct password is in the non-text/plain part, so it is ignored.
     --AAA
     Content-Type: application/x-ignore
     <BLANKLINE>
-    Approve: abcxyz
+    Approved: abcxyz
     The above line will be ignored.
     <BLANKLINE>
     --AAA
@@ -368,8 +354,14 @@ Here, the correct password is in the non-text/plain part, so it is ignored.
     <BLANKLINE>
     An important message.
     --AAA--
-    >>> msgdata
-    {}
+
+
+Stripping text/html parts
+-------------------------
+
+Because some mail readers will include both a text/plain part and a text/html
+alternative, the 'approved' rule has to search the alternatives and strip
+anything that looks like an Approve or Approved headers.
 
     >>> msg = message_from_string(u"""\
     ... From: aperson@example.com
@@ -377,30 +369,100 @@ Here, the correct password is in the non-text/plain part, so it is ignored.
     ... Content-Type: multipart/mixed; boundary="AAA"
     ...
     ... --AAA
-    ... Content-Type: application/x-ignore
+    ... Content-Type: text/html
+    ...
+    ... <html>
+    ... <head></head>
+    ... <body>
+    ... <b>Approved: abcxyz</b>
+    ... <p>The above line will be ignored.
+    ... </body>
+    ... </html>
+    ...
+    ... --AAA
+    ... Content-Type: text/plain
     ...
     ... Approved: abcxyz
-    ... The above line will be ignored.
+    ... An important message.
+    ... --AAA--
+    ... """)
+    >>> rule.check(mlist, msg, {})
+    True
+
+And the header-like text in the text/html part was stripped.
+
+    >>> print msg.as_string()
+    From: aperson@example.com
+    MIME-Version: 1.0
+    Content-Type: multipart/mixed; boundary="AAA"
+    <BLANKLINE>
+    --AAA
+    Content-Transfer-Encoding: 7bit
+    MIME-Version: 1.0
+    Content-Type: text/html; charset="us-ascii"
+    <BLANKLINE>
+    <html>
+    <head></head>
+    <body>
+    <b></b>
+    <p>The above line will be ignored.
+    </body>
+    </html>
+    <BLANKLINE>
+    --AAA
+    Content-Transfer-Encoding: 7bit
+    MIME-Version: 1.0
+    Content-Type: text/plain; charset="us-ascii"
+    <BLANKLINE>
+    An important message.
+    --AAA--
+    <BLANKLINE>
+
+This is true even if the rule does not match.
+
+    >>> msg = message_from_string(u"""\
+    ... From: aperson@example.com
+    ... MIME-Version: 1.0
+    ... Content-Type: multipart/mixed; boundary="AAA"
+    ...
+    ... --AAA
+    ... Content-Type: text/html
+    ...
+    ... <html>
+    ... <head></head>
+    ... <body>
+    ... <b>Approve: 123456</b>
+    ... <p>The above line will be ignored.
+    ... </body>
+    ... </html>
     ...
     ... --AAA
     ... Content-Type: text/plain
     ...
-    ... Approved: 123456
+    ... Approve: 123456
     ... An important message.
     ... --AAA--
     ... """)
-    >>> msgdata = {}
-    >>> process(mlist, msg, msgdata)
+    >>> rule.check(mlist, msg, {})
+    False
+
     >>> print msg.as_string()
     From: aperson@example.com
     MIME-Version: 1.0
     Content-Type: multipart/mixed; boundary="AAA"
     <BLANKLINE>
     --AAA
-    Content-Type: application/x-ignore
+    Content-Transfer-Encoding: 7bit
+    MIME-Version: 1.0
+    Content-Type: text/html; charset="us-ascii"
     <BLANKLINE>
-    Approved: abcxyz
-    The above line will be ignored.
+    <html>
+    <head></head>
+    <body>
+    <b></b>
+    <p>The above line will be ignored.
+    </body>
+    </html>
     <BLANKLINE>
     --AAA
     Content-Transfer-Encoding: 7bit
@@ -410,5 +472,3 @@ Here, the correct password is in the non-text/plain part, so it is ignored.
     An important message.
     --AAA--
     <BLANKLINE>
-    >>> msgdata
-    {}
diff --git a/Mailman/interfaces/rules.py b/Mailman/interfaces/rules.py
index 5ef741852..13edcf481 100644
--- a/Mailman/interfaces/rules.py
+++ b/Mailman/interfaces/rules.py
@@ -35,6 +35,7 @@ class IRule(Interface):
     def check(mlist, msg, msgdata):
         """Run the rule.
 
+        :param mlist: The mailing list object.
         :param msg: The message object.
         :param msgdata: The message metadata.
         :return: A boolean specifying whether the rule was matched or not.
@@ -45,7 +46,7 @@ class IRule(Interface):
 class IRuleSet(Interface):
     """A rule processor."""
 
-    rules = Attribute('The set of all rules this processor knows about')
+    rules = Attribute('The set of all rules this processor knows about.')
 
     def __getitem__(rule_name):
         """Return the named rule.
diff --git a/Mailman/rules/approved.py b/Mailman/rules/approved.py
new file mode 100644
index 000000000..e5c13f770
--- /dev/null
+++ b/Mailman/rules/approved.py
@@ -0,0 +1,119 @@
+# 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 matching Approve header."""
+
+__all__ = ['approve_rule']
+__metaclass__ = type
+
+
+import re
+from email.iterators import typed_subpart_iterator
+from zope.interface import implements
+
+from Mailman.i18n import _
+from Mailman.interfaces import IRule
+
+
+EMPTYSTRING = u''
+
+
+
+class Approved:
+    implements(IRule)
+
+    name = 'approved'
+    description = _('The message has a matching Approve or Approved header.')
+
+    def check(self, mlist, msg, msgdata):
+        """See `IRule`."""
+        # See if the message has an Approved or Approve header with a valid
+        # moderator password.  Also look at the first non-whitespace line in
+        # the file to see if it looks like an Approved header.
+        missing = object()
+        password = msg.get('approved', msg.get('approve', missing))
+        if password is missing:
+            # Find the first text/plain part in the message
+            part = None
+            stripped = False
+            for part in typed_subpart_iterator(msg, 'text', 'plain'):
+                break
+            payload = part.get_payload(decode=True)
+            if payload is not None:
+                lines = payload.splitlines(True)
+                for lineno, line in enumerate(lines):
+                    if line.strip() <> '':
+                        break
+                if ':' in line:
+                    header, value = line.split(':', 1)
+                    if header.lower() in ('approved', 'approve'):
+                        password = value.strip()
+                        # Now strip the first line from the payload so the
+                        # password doesn't leak.
+                        del lines[lineno]
+                        reset_payload(part, EMPTYSTRING.join(lines))
+                        stripped = True
+            if stripped:
+                # Now try all the text parts in case it's
+                # multipart/alternative with the approved line in HTML or
+                # other text part.  We make a pattern from the Approved line
+                # and delete it from all text/* parts in which we find it.  It
+                # would be better to just iterate forward, but email
+                # compatability for pre Python 2.2 returns a list, not a true
+                # iterator.
+                #
+                # This will process all the multipart/alternative parts in the
+                # message as well as all other text parts.  We shouldn't find
+                # the pattern outside the multipart/alternative parts, but if
+                # we do, it is probably best to delete it anyway as it does
+                # contain the password.
+                #
+                # Make a pattern to delete.  We can't just delete a line
+                # because line of HTML or other fancy text may include
+                # additional message text.  This pattern works with HTML.  It
+                # may not work with rtf or whatever else is possible.
+                pattern = header + ':(\s|&nbsp;)*' + re.escape(password)
+                for part in typed_subpart_iterator(msg, 'text'):
+                    payload = part.get_payload(decode=True)
+                    if payload is not None:
+                        if re.search(pattern, payload):
+                            reset_payload(part, re.sub(pattern, '', payload))
+        else:
+            del msg['approved']
+            del msg['approve']
+        return password is not missing and password == mlist.moderator_password
+
+
+
+def reset_payload(part, payload):
+    # Set decoded payload maintaining content-type, charset, format and delsp.
+    charset = part.get_content_charset() or 'us-ascii'
+    content_type = part.get_content_type()
+    format = part.get_param('format')
+    delsp = part.get_param('delsp')
+    del part['content-transfer-encoding']
+    del part['content-type']
+    part.set_payload(payload, charset)
+    part.set_type(content_type)
+    if format:
+        part.set_param('Format', format)
+    if delsp:
+        part.set_param('DelSp', delsp)
+
+
+
+approve_rule = Approved()
diff --git a/Mailman/rules/emergency.py b/Mailman/rules/emergency.py
index 088ba4ec8..16cb0db8a 100644
--- a/Mailman/rules/emergency.py
+++ b/Mailman/rules/emergency.py
@@ -17,7 +17,7 @@
 
 """The emergency hold rule."""
 
-__all__ = ['Emergency']
+__all__ = ['emergency_rule']
 __metaclass__ = type