I have a command as follows:
class AddChatMessages(Command):
arguments = [
('messages', AmpList([('message', Unicode()), ('type', Integer())]))]
And I have a responder for it in a controller:
def add_chat_messages(self, messages):
for i, m in enumerate(messages):
messages[i] = (m['message'], m['type'])
self.main.add_chat_messages(messages)
return {}
commands.AddChatMessages.responder(add_chat_messages)
I am writing a unit test for it. This is my code:
class AddChatMessagesTest(ProtocolTestMixin, unittest.TestCase):
command = commands.AddChatMessages
data = {'messages': [{'message': 'hi', 'type': 'None'}]}
def assert_callback(self, unused):
pass
Where ProtocolMixin is as follows:
class ProtocolTestMixin(object):
def setUp(self):
self.protocol = client.CommandProtocol()
def assert_callback(self, unused):
raise NotImplementedError("Has to be implemented!")
def test_responder(self):
responder = self.protocol.lookupFunction(
self.command.commandName)
d = responder(self.data)
d.addCallback(self.assert_callback)
return d
It works if AmpList is not involved, but when it is - I get following error:
======================================================================
ERROR: test_responder
----------------------------------------------------------------------
Traceback (most recent call last):
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/internet/defer.py", line 139, in maybeDeferred
result = f(*args, **kw)
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/internet/utils.py", line 203, in runWithWarningsSuppressed
reraise(exc_info[1], exc_info[2])
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/internet/utils.py", line 199, in runWithWarningsSuppressed
result = f(*a, **kw)
File "/Users/<username>/Projects/space/tests/client_test.py", line 32, in test_responder
d = responder(self.data)
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/protocols/amp.py", line 1016, in doit
kw = command.parseArguments(box, self)
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/protocols/amp.py", line 1717, in parseArguments
return _stringsToObjects(box, cls.arguments, protocol)
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/protocols/amp.py", line 2510, in _stringsToObjects
argparser.fromBox(argname, myStrings, objects, proto)
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/protocols/amp.py", line 1209, in fromBox
objects[nk] = self.fromStringProto(st, proto)
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/protocols/amp.py", line 1465, in fromStringProto
boxes = parseString(inString)
File "/Users/<username>/Projects/space/env/lib/python2.7/site-packages/twisted/protocols/amp.py", line 2485, in parseString
return cls.parse(StringIO(data))
TypeError: must be string or buffer, not list
Which makes sense, but how do I serialize a list in AddChatMessagesTest.data?
The responder expects to be called with a serialized box. It will then deserialize it, dispatch the objects to application code, take the object the application code returns, serialize it, and then return that serialized form.
For a few AMP types. most notably String, the serialized form is the same as the deserialized form, so it's easy to overlook this.
I think that you'll want to pass your data through Command.makeArguments in order to produce an object suitable to pass to a responder.
For example:
>>> from twisted.protocols.amp import Command, Integer
>>> class Foo(Command):
... arguments = [("bar", Integer())]
...
>>> Foo.makeArguments({"bar": 17}, None)
AmpBox({'bar': '17'})
>>>
If you do this with a Command that uses AmpList I think you'll find makeArguments returns an encoded string for the value of that argument and that the responder is happy to accept and parse that kind of string.