Port the maximum message size check to a rule. Add doctest.

Rename the implicit.txt doctest.

specialized_message_from_string(): Mimic the way the text->message parser will
include the size of the original text as an attribute on the message object.
The maximum message size rule will use this information.

8 files changed, 110 insertions, 41 deletions

diff --git a/Mailman/Handlers/Hold.py b/Mailman/Handlers/Hold.py
index 12bab8a8b..81dab3189 100644
--- a/Mailman/Handlers/Hold.py
+++ b/Mailman/Handlers/Hold.py
@@ -165,22 +165,6 @@ def process(mlist, msg, msgdata):
             # message because the info would also go to the sender
             hold_for_approval(mlist, msg, msgdata, SuspiciousHeaders)
             # no return
-    #
-    # Is the message too big?
-    if mlist.max_message_size > 0:
-        bodylen = 0
-        for line in email.Iterators.body_line_iterator(msg):
-            bodylen += len(line)
-        for part in msg.walk():
-            if part.preamble:
-                bodylen += len(part.preamble)
-            if part.epilogue:
-                bodylen += len(part.epilogue)
-        if bodylen/1024.0 > mlist.max_message_size:
-            hold_for_approval(mlist, msg, msgdata,
-                              MessageTooBig(bodylen, mlist.max_message_size))
-            # no return
-    #
     # Are we gatewaying to a moderated newsgroup and is this list the
     # moderator's address for the group?
     if mlist.news_moderation == 2:
diff --git a/Mailman/docs/hold.txt b/Mailman/docs/hold.txt
index ed3fabdf0..16948331f 100644
--- a/Mailman/docs/hold.txt
+++ b/Mailman/docs/hold.txt
@@ -96,28 +96,6 @@ Just a bit of clean up.
     >>> mlist.bounce_matching_headers = None
 
 
-Message size
-------------
-
-Mailman can hold messages that are bigger than a given size.  Generally this
-is used to prevent huge attachments from getting posted to the list.  This
-value is calculated in terms of KB (1024 bytes).
-
-    >>> mlist.max_message_size = 1
-    >>> one_line = 'x' * 79
-    >>> big_body = '\n'.join([one_line] * 15)
-    >>> msg = message_from_string("""\
-    ... From: aperson@example.com
-    ... To: _xtest@example.com
-    ...
-    ... """ + big_body)
-    >>> process(mlist, msg, {})
-    Traceback (most recent call last):
-    ...
-    MessageTooBig
-    >>> clear()
-
-
 X Hold Notifications
 X ------------------
 X 
diff --git a/Mailman/docs/implicit.txt b/Mailman/docs/implicit-dest.txt
index 967ddc8c7..b6fed2769 100644
--- a/Mailman/docs/implicit.txt
+++ b/Mailman/docs/implicit-dest.txt
@@ -11,7 +11,7 @@ not explicitly mentioned in the set of message recipients.
     >>> rule.name
     'implicit-dest'
 
-Mailman will hold messages that have implicit destination, meaning that the
+This rule matches messages that have implicit destination, meaning that the
 mailing list's posting address isn't included in the explicit recipients.
 
     >>> mlist.require_explicit_destination = True
diff --git a/Mailman/docs/max-size.txt b/Mailman/docs/max-size.txt
new file mode 100644
index 000000000..b477ecd2b
--- /dev/null
+++ b/Mailman/docs/max-size.txt
@@ -0,0 +1,41 @@
+Message size
+============
+
+The 'message-size' rule matches when the posted message is bigger than a
+specified maximum.  Generally this is used to prevent huge attachments from
+getting posted to the list.  This value is calculated in terms of KB (1024
+bytes).
+
+    >>> from Mailman.configuration import config
+    >>> mlist = config.db.list_manager.create(u'_xtest@example.com')
+    >>> from Mailman.app.rules import find_rule
+    >>> rule = find_rule('max-size')
+    >>> rule.name
+    'max-size'
+
+For example, setting the maximum message size to 1 means that any message
+bigger than that will match the rule.
+
+    >>> mlist.max_message_size = 1 # 1024 bytes
+    >>> one_line = u'x' * 79
+    >>> big_body = u'\n'.join([one_line] * 15)
+    >>> msg = message_from_string(u"""\
+    ... From: aperson@example.com
+    ... To: _xtest@example.com
+    ...
+    ... """ + big_body)
+    >>> rule.check(mlist, msg, {})
+    True
+
+Setting the maximum message size to zero means no size check is performed.
+
+    >>> mlist.max_message_size = 0
+    >>> rule.check(mlist, msg, {})
+    False
+
+Of course, if the maximum size is larger than the message's size, then it's
+still okay.
+
+    >>> mlist.max_message_size = msg.original_size/1024.0 + 1
+    >>> rule.check(mlist, msg, {})
+    False
diff --git a/Mailman/queue/__init__.py b/Mailman/queue/__init__.py
index c415834ba..6a1873d60 100644
--- a/Mailman/queue/__init__.py
+++ b/Mailman/queue/__init__.py
@@ -140,7 +140,13 @@ class Switchboard:
             msg = cPickle.load(fp)
             data = cPickle.load(fp)
         if data.get('_parsemsg'):
+            # Calculate the original size of the text now so that we won't
+            # have to generate the message later when we do size restriction
+            # checking.
+            original_size = len(msg)
             msg = email.message_from_string(msg, Message.Message)
+            msg.original_size = original_size
+            data['original_size'] = original_size
         return msg, data
 
     def finish(self, filebase, preserve=False):
diff --git a/Mailman/rules/implicit_dest.py b/Mailman/rules/implicit_dest.py
index 8c9ba8899..e056a2e9e 100644
--- a/Mailman/rules/implicit_dest.py
+++ b/Mailman/rules/implicit_dest.py
@@ -23,7 +23,6 @@ __metaclass__ = type
 
 import re
 from email.utils import getaddresses
-from itertools import chain
 from zope.interface import implements
 
 from Mailman.i18n import _
diff --git a/Mailman/rules/max_size.py b/Mailman/rules/max_size.py
new file mode 100644
index 000000000..1e62b2ad8
--- /dev/null
+++ b/Mailman/rules/max_size.py
@@ -0,0 +1,49 @@
+# 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.
+
+"""The maximum message size rule."""
+
+__all__ = ['max_size']
+__metaclass__ = type
+
+
+from zope.interface import implements
+
+from Mailman.i18n import _
+from Mailman.interfaces import IRule
+
+
+
+class MaximumSize:
+    """The implicit destination rule."""
+    implements(IRule)
+
+    name = 'max-size'
+    description = _('Catch messages that are bigger than a specified maximum.')
+
+    def check(self, mlist, msg, msgdata):
+        """See `IRule`."""
+        if mlist.max_message_size == 0:
+            return False
+        assert hasattr(msg, 'original_size'), (
+            'Message was not sized on initial parsing.')
+        # The maximum size is specified in 1024 bytes.
+        return msg.original_size / 1024.0 > mlist.max_message_size
+
+
+
+max_size = MaximumSize()
diff --git a/Mailman/tests/test_documentation.py b/Mailman/tests/test_documentation.py
index 390ba6a66..36b3c7ecb 100644
--- a/Mailman/tests/test_documentation.py
+++ b/Mailman/tests/test_documentation.py
@@ -36,7 +36,19 @@ COMMASPACE = ', '
 
 
 def specialized_message_from_string(text):
-    return message_from_string(text, Message)
+    """Parse text into a message object.
+
+    This is specialized in the sense that an instance of Mailman's own Message
+    object is returned, and this message object has an attribute
+    `original_size` which is the pre-calculated size in bytes of the message's
+    text representation.
+    """
+    # This mimic what Switchboard.dequeue() does when parsing a message from
+    # text into a Message instance.
+    original_size = len(text)
+    message = message_from_string(text, Message)
+    message.original_size = original_size
+    return message
 
 
 def setup(testobj):