3 files changed, 34 insertions, 1 deletions

diff --git a/src/mailman/rest/post_moderation.py b/src/mailman/rest/post_moderation.py
index fc38af359..ee31e8694 100644
--- a/src/mailman/rest/post_moderation.py
+++ b/src/mailman/rest/post_moderation.py
@@ -71,7 +71,13 @@ class _HeldMessageBase(_ModerationBase):
         # resource.  XXX See LP: #967954
         key = resource.pop('key')
         msg = getUtility(IMessageStore).get_message_by_id(key)
-        resource['msg'] = msg.as_string()
+        try:
+            resource['msg'] = msg.as_string()
+        except KeyError:
+            # If the message can't be parsed, return a generic message instead
+            # of raising an error.
+            # See http://bugs.python.org/issue27321 and #256
+            resource['msg'] = 'this message is defective'
         # Some of the _mod_* keys we want to rename and place into the JSON
         # resource.  Others we can drop.  Since we're mutating the dictionary,
         # we need to make a copy of the keys.  When you port this to Python 3,
diff --git a/src/mailman/rest/tests/data/bad_email b/src/mailman/rest/tests/data/bad_email
new file mode 100644
index 000000000..83f9337dd
--- /dev/null
+++ b/src/mailman/rest/tests/data/bad_email
@@ -0,0 +1,8 @@
+To: <test@example.com>
+Subject: =?koi8-r?B?UF9AX/NfQ1/5X+xfS1/p?=
+From: =?koi8-r?B?8sXL0sXB1MnXzs/FIMHHxc7U09TXzw==?=
+Content-Type: text/plain; charset=koi8-r
+Message-Id: <20160614102505.9OFQ19L1C>
+
+ώτο ταλοε ςελμανξαρ ςασσωμλα?
+λΑΛΟΚ ΟΤΛΜΙΛ ΦΔΑΤΨ ΟΤ άΤΟΗΟ ΝΕΤΟΔΑ ΠΟΙΣΛΑ ΛΜΙΕΞΤΟΧ?
diff --git a/src/mailman/rest/tests/test_moderation.py b/src/mailman/rest/tests/test_moderation.py
index e0c3f1ccf..03d52dfc4 100644
--- a/src/mailman/rest/tests/test_moderation.py
+++ b/src/mailman/rest/tests/test_moderation.py
@@ -17,8 +17,10 @@
 
 """REST moderation tests."""
 
+import os
 import unittest
 
+from email import message_from_binary_file
 from mailman.app.lifecycle import create_list
 from mailman.app.moderator import hold_message
 from mailman.database.transaction import transaction
@@ -206,6 +208,23 @@ class TestSubscriptionModeration(unittest.TestCase):
         emails = set(json['email'] for json in content['entries'])
         self.assertEqual(emails, {'anne@example.com', 'bart@example.com'})
 
+    def test_view_malformed_held_message(self):
+        # Opening a bad (i.e. bad structure) email and holding it.
+        pwd = os.path.dirname(os.path.realpath(__file__))
+        email_path = os.path.join(pwd, 'data/bad_email')
+        msg = message_from_binary_file(open(email_path, 'rb'))
+        msg.sender = 'bogussender@example.com'
+        with transaction():
+            hold_message(self._mlist, msg)
+        # Now trying to access held messages from REST API should not give
+        # 500 server error if one of the messages can't be parsed properly.
+        content, response = call_api(
+            'http://localhost:9001/3.0/lists/ant@example.com/held')
+        self.assertEqual(response.status, 200)
+        self.assertEqual(len(content['entries']), 1)
+        self.assertEqual(content['entries'][0]['msg'],
+                         'this message is defective')
+
     def test_individual_request(self):
         # We can view an individual request.
         with transaction():