Echo_bot: prevent loops when decrypting/encrypting

Signed-off-by: Maxime “pep” Buquet <pep@bouah.net>

examples/echo_client.py

@@ -88,6 +88,7 @@ class EchoBot(ClientXMPP):
             encrypted = msg['omemo_encrypted']
             body = self['xep_0384'].decrypt_message(encrypted, mfrom, allow_untrusted)
             await self.encrypted_reply(msg, 'Thanks for sending\n%s' % body.decode("utf8"))
+            return None
         except (MissingOwnKey,):
             # The message is missing our own key, it was not encrypted for
             # us, and we can't decrypt it.
@@ -95,6 +96,7 @@ class EchoBot(ClientXMPP):
                 msg,
                 'I can\'t decrypt this message as it is not encrypted for me.',
             )
+            return None
         except (NoAvailableSession,) as exn:
             # We received a message from that contained a session that we
             # don't know about (deleted session storage, etc.). We can't
@@ -107,6 +109,7 @@ class EchoBot(ClientXMPP):
                 'I can\'t decrypt this message as it uses an encrypted '
                 'session I don\'t know about.',
             )
+            return None
         except (UndecidedException, UntrustedException) as exn:
             # We received a message from an untrusted device. We can
             # choose to decrypt the message nonetheless, with the
@@ -122,11 +125,13 @@ class EchoBot(ClientXMPP):
             )
             # We resend, setting the `allow_untrusted` parameter to True.
             await self.message(msg, allow_untrusted=True)
+            return None
         except (EncryptionPrepareException,):
             # Slixmpp tried its best, but there were errors it couldn't
             # resolve. At this point you should have seen other exceptions
             # and given a chance to resolve them already.
             await self.plain_reply(msg, 'I was not able to decrypt the message.')
+            return None
         except (Exception,) as exn:
             await self.plain_reply(msg, 'An error occured while attempting decryption.\n%r' % exn)
             raise