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'Release_2_1-maint'.

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diff --git a/Mailman/Handlers/MimeDel.py b/Mailman/Handlers/MimeDel.py
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+# Copyright (C) 2002 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+"""MIME-stripping filter for Mailman.
+
+This module scans a message for MIME content, removing those sections whose
+MIME types match one of a list of matches.  multipart/alternative sections are
+replaced by the first non-empty component, and multipart/mixed sections
+wrapping only single sections after other processing are replaced by their
+contents.
+"""
+
+import os
+import errno
+import tempfile
+
+from email.Iterators import typed_subpart_iterator
+
+from Mailman import mm_cfg
+from Mailman import Errors
+from Mailman.Message import UserNotification
+from Mailman.Queue.sbcache import get_switchboard
+from Mailman.Logging.Syslog import syslog
+from Mailman.Version import VERSION
+from Mailman.i18n import _
+
+
+
+def process(mlist, msg, msgdata):
+    # Short-circuits
+    if not mlist.filter_content:
+        return
+    if msgdata.get('isdigest'):
+        return
+    # We also don't care about our own digests or plaintext
+    ctype = msg.get_content_type()
+    mtype = msg.get_content_maintype()
+    # Check to see if the outer type matches one of the filter types
+    filtertypes = mlist.filter_mime_types
+    passtypes = mlist.pass_mime_types
+    if ctype in filtertypes or mtype in filtertypes:
+        dispose(mlist, msg, msgdata,
+                _("The message's content type was explicitly disallowed"))
+    # Check to see if there is a pass types and the outer type doesn't match
+    # one of these types
+    if passtypes and not (ctype in passtypes or mtype in passtypes):
+        dispose(mlist, msg, msgdata,
+                _("The message's content type was not explicitly allowed"))
+    numparts = len([subpart for subpart in msg.walk()])
+    # If the message is a multipart, filter out matching subparts
+    if msg.is_multipart():
+        # Recursively filter out any subparts that match the filter list
+        prelen = len(msg.get_payload())
+        filter_parts(msg, filtertypes, passtypes)
+        # If the outer message is now an empty multipart (and it wasn't
+        # before!) then, again it gets discarded.
+        postlen = len(msg.get_payload())
+        if postlen == 0 and prelen > 0:
+            dispose(mlist, msg, msgdata,
+                    _("After content filtering, the message was empty"))
+    # Now replace all multipart/alternatives with just the first non-empty
+    # alternative.  BAW: We have to special case when the outer part is a
+    # multipart/alternative because we need to retain most of the outer part's
+    # headers.  For now we'll move the subpart's payload into the outer part,
+    # and then copy over its Content-Type: and Content-Transfer-Encoding:
+    # headers (any others?).
+    collapse_multipart_alternatives(msg)
+    if ctype == 'multipart/alternative':
+        firstalt = msg.get_payload(0)
+        reset_payload(msg, firstalt)
+    # If we removed some parts, make note of this
+    changedp = 0
+    if numparts <> len([subpart for subpart in msg.walk()]):
+        changedp = 1
+    # Now perhaps convert all text/html to text/plain
+    if mlist.convert_html_to_plaintext and mm_cfg.HTML_TO_PLAIN_TEXT_COMMAND:
+        changedp += to_plaintext(msg)
+    # If we're left with only two parts, an empty body and one attachment,
+    # recast the message to one of just that part
+    if msg.is_multipart() and len(msg.get_payload()) == 2:
+        if msg.get_payload(0).get_payload() == '':
+            useful = msg.get_payload(1)
+            reset_payload(msg, useful)
+            changedp = 1
+    if changedp:
+        msg['X-Content-Filtered-By'] = 'Mailman/MimeDel %s' % VERSION
+
+
+
+def reset_payload(msg, subpart):
+    # Reset payload of msg to contents of subpart, and fix up content headers
+    payload = subpart.get_payload()
+    msg.set_payload(payload)
+    del msg['content-type']
+    del msg['content-transfer-encoding']
+    del msg['content-disposition']
+    del msg['content-description']
+    msg['Content-Type'] = subpart.get('content-type', 'text/plain')
+    cte = subpart.get('content-transfer-encoding')
+    if cte:
+        msg['Content-Transfer-Encoding'] = cte
+    cdisp = subpart.get('content-disposition')
+    if cdisp:
+        msg['Content-Disposition'] = cdisp
+    cdesc = subpart.get('content-description')
+    if cdesc:
+        msg['Content-Description'] = cdesc
+
+
+
+def filter_parts(msg, filtertypes, passtypes):
+    # Look at all the message's subparts, and recursively filter
+    if not msg.is_multipart():
+        return 1
+    payload = msg.get_payload()
+    prelen = len(payload)
+    newpayload = []
+    for subpart in payload:
+        keep = filter_parts(subpart, filtertypes, passtypes)
+        if not keep:
+            continue
+        ctype = subpart.get_content_type()
+        mtype = subpart.get_content_maintype()
+        if ctype in filtertypes or mtype in filtertypes:
+            # Throw this subpart away
+            continue
+        if passtypes and not (ctype in passtypes or mtype in passtypes):
+            # Throw this subpart away
+            continue
+        newpayload.append(subpart)
+    # Check to see if we discarded all the subparts
+    postlen = len(newpayload)
+    msg.set_payload(newpayload)
+    if postlen == 0 and prelen > 0:
+        # We threw away everything
+        return 0
+    return 1
+
+
+
+def collapse_multipart_alternatives(msg):
+    if not msg.is_multipart():
+        return
+    newpayload = []
+    for subpart in msg.get_payload():
+        if subpart.get_content_type() == 'multipart/alternative':
+            try:
+                firstalt = subpart.get_payload(0)
+                newpayload.append(firstalt)
+            except IndexError:
+                pass
+        else:
+            newpayload.append(subpart)
+    msg.set_payload(newpayload)
+
+
+
+def to_plaintext(msg):
+    changedp = 0
+    for subpart in typed_subpart_iterator(msg, 'text', 'html'):
+        filename = tempfile.mktemp('.html')
+        fp = open(filename, 'w')
+        try:
+            fp.write(subpart.get_payload())
+            fp.close()
+            cmd = os.popen(mm_cfg.HTML_TO_PLAIN_TEXT_COMMAND %
+                           {'filename': filename})
+            plaintext = cmd.read()
+            rtn = cmd.close()
+            if rtn:
+                syslog('error', 'HTML->text/plain error: %s', rtn)
+        finally:
+            try:
+                os.unlink(filename)
+            except OSError, e:
+                if e.errno <> errno.ENOENT: raise
+        # Now replace the payload of the subpart and twiddle the Content-Type:
+        subpart.set_payload(plaintext)
+        subpart.set_type('text/plain')
+        changedp = 1
+    return changedp
+
+
+
+def dispose(mlist, msg, msgdata, why):
+    # filter_action == 0 just discards, see below
+    if mlist.filter_action == 1:
+        # Bounce the message to the original author
+        raise Errors.RejectMessage, why
+    if mlist.filter_action == 2:
+        # Forward it on to the list owner
+        listname = mlist.internal_name()
+        mlist.ForwardMessage(
+            msg,
+            text=_("""\
+The attached message matched the %(listname)s mailing list's content filtering
+rules and was prevented from being forwarded on to the list membership.  You
+are receiving the only remaining copy of the discarded message.
+
+"""),
+            subject=_('Content filtered message notification'))
+    if mlist.filter_action == 3 and \
+           mm_cfg.OWNERS_CAN_PRESERVE_FILTERED_MESSAGES:
+        badq = get_switchboard(mm_cfg.BADQUEUE_DIR)
+        badq.enqueue(msg, msgdata)
+    # Most cases also discard the message
+    raise Errors.DiscardMessage