email_mirror: Ignore stream_name part of receiving address.

To prepare for changing how the stream name gets encoded into mirror
email addresses while making sure old addresses keep working, we ignore
the stream_name part when receiving emails into the mirror and we only
look at the email_token to identify into which stream to mirror the
email.

zerver/lib/actions.py

@@ -4480,9 +4480,9 @@ def get_email_gateway_message_string_from_address(address: str) -> Optional[str]
 
     return msg_string
 
-def decode_email_address(email: str) -> Optional[Tuple[str, str, bool]]:
+def decode_email_address(email: str) -> Optional[Tuple[str, bool]]:
     # Perform the reverse of encode_email_address. Returns a tuple of
-    # (streamname, email_token, show_sender)
+    # (email_token, show_sender)
     msg_string = get_email_gateway_message_string_from_address(email)
     if msg_string is None:
         return None
@@ -4500,8 +4500,7 @@ def decode_email_address(email: str) -> Optional[Tuple[str, str, bool]]:
     else:
         encoded_stream_name, token = msg_string.split('+')
 
-    stream_name = re.sub(r"%\d{4}", lambda x: chr(int(x.group(0)[1:])), encoded_stream_name)
-    return stream_name, token, show_sender
+    return token, show_sender
 
 SubHelperT = Tuple[List[Dict[str, Any]], List[Dict[str, Any]], List[Dict[str, Any]]]
 

zerver/lib/email_mirror.py

@@ -208,13 +208,6 @@ def send_zulip(sender: str, stream: Stream, topic: str, content: str) -> None:
         truncate_body(content),
         email_gateway=True)
 
-def valid_stream(stream_name: str, token: str) -> bool:
-    try:
-        stream = Stream.objects.get(email_token=token)
-        return stream.name.lower() == stream_name.lower()
-    except Stream.DoesNotExist:
-        return False
-
 def get_message_part_by_type(message: message.Message, content_type: str) -> Optional[str]:
     charsets = message.get_charsets()
 
@@ -298,12 +291,14 @@ def extract_and_validate(email: str) -> Tuple[Stream, bool]:
     temp = decode_email_address(email)
     if temp is None:
         raise ZulipEmailForwardError("Malformed email recipient " + email)
-    stream_name, token, show_sender = temp
+    token, show_sender = temp
 
-    if not valid_stream(stream_name, token):
+    try:
+        stream = Stream.objects.get(email_token=token)
+    except Stream.DoesNotExist:
         raise ZulipEmailForwardError("Bad stream token from email recipient " + email)
 
-    return Stream.objects.get(email_token=token), show_sender
+    return stream, show_sender
 
 def find_emailgateway_recipient(message: message.Message) -> str:
     # We can't use Delivered-To; if there is a X-Gm-Original-To

zerver/tests/test_email_mirror.py

@@ -57,9 +57,8 @@ class TestEncodeDecode(ZulipTestCase):
         self.assertTrue(email_address.endswith('@testserver'))
         tup = decode_email_address(email_address)
         assert tup is not None
-        (decoded_stream_name, token, show_sender) = tup
+        token, show_sender = tup
         self.assertFalse(show_sender)
-        self.assertEqual(decoded_stream_name, stream_name)
         self.assertEqual(token, stream.email_token)
 
         parts = email_address.split('@')
@@ -67,25 +66,22 @@ class TestEncodeDecode(ZulipTestCase):
         email_address_show = '@'.join(parts)
         tup = decode_email_address(email_address_show)
         assert tup is not None
-        (decoded_stream_name, token, show_sender) = tup
+        token, show_sender = tup
         self.assertTrue(show_sender)
-        self.assertEqual(decoded_stream_name, stream_name)
         self.assertEqual(token, stream.email_token)
 
         email_address_dots = email_address.replace('+', '.')
         tup = decode_email_address(email_address_dots)
         assert tup is not None
-        (decoded_stream_name, token, show_sender) = tup
+        token, show_sender = tup
         self.assertFalse(show_sender)
-        self.assertEqual(decoded_stream_name, stream_name)
         self.assertEqual(token, stream.email_token)
 
         email_address_dots_show = email_address_show.replace('+', '.')
         tup = decode_email_address(email_address_dots_show)
         assert tup is not None
-        (decoded_stream_name, token, show_sender) = tup
+        token, show_sender = tup
         self.assertTrue(show_sender)
-        self.assertEqual(decoded_stream_name, stream_name)
         self.assertEqual(token, stream.email_token)
 
         email_address = email_address.replace('@testserver', '@zulip.org')
@@ -96,20 +92,29 @@ class TestEncodeDecode(ZulipTestCase):
         with self.settings(EMAIL_GATEWAY_EXTRA_PATTERN_HACK='@zulip.org'):
             tup = decode_email_address(email_address)
             assert tup is not None
-            (decoded_stream_name, token, show_sender) = tup
+            token, show_sender = tup
             self.assertFalse(show_sender)
-            self.assertEqual(decoded_stream_name, stream_name)
             self.assertEqual(token, stream.email_token)
 
             tup = decode_email_address(email_address_show)
             assert tup is not None
-            (decoded_stream_name, token, show_sender) = tup
+            token, show_sender = tup
             self.assertTrue(show_sender)
-            self.assertEqual(decoded_stream_name, stream_name)
             self.assertEqual(token, stream.email_token)
 
         self.assertEqual(decode_email_address('bogus'), None)
 
+    def test_decode_ignores_stream_name(self) -> None:
+        stream = get_stream("Denmark", get_realm("zulip"))
+        stream_to_address = encode_email_address(stream)
+        stream_to_address = stream_to_address.replace("Denmark", "Some_name")
+
+        # get the email_token:
+        tup = decode_email_address(stream_to_address)
+        assert tup is not None
+        token = tup[0]
+        self.assertEqual(token, stream.email_token)
+
 class TestEmailMirrorLibrary(ZulipTestCase):
     def test_get_missed_message_token(self) -> None:
 
@@ -643,7 +648,11 @@ class TestEmailMirrorTornadoView(ZulipTestCase):
     def test_error_to_stream_with_wrong_address(self) -> None:
         stream = get_stream("Denmark", get_realm("zulip"))
         stream_to_address = encode_email_address(stream)
-        stream_to_address = stream_to_address.replace("Denmark", "Wrong_stream")
+        # get the email_token:
+        tup = decode_email_address(stream_to_address)
+        assert tup is not None
+        token = tup[0]
+        stream_to_address = stream_to_address.replace(token, "Wrong_token")
 
         result = self.send_offline_message(stream_to_address, self.example_email('hamlet'))
         self.assert_json_error(
@@ -651,6 +660,14 @@ class TestEmailMirrorTornadoView(ZulipTestCase):
             "5.1.1 Bad destination mailbox address: "
             "Please use the address specified in your Streams page.")
 
+    def test_success_to_stream_with_good_token_wrong_stream_name(self) -> None:
+        stream = get_stream("Denmark", get_realm("zulip"))
+        stream_to_address = encode_email_address(stream)
+        stream_to_address = stream_to_address.replace("Denmark", "Wrong_name")
+
+        result = self.send_offline_message(stream_to_address, self.example_email('hamlet'))
+        self.assert_json_success(result)
+
     def test_success_to_private(self) -> None:
         mm_address = self.send_private_message()
         result = self.send_offline_message(mm_address, self.example_email('cordelia'))