Add controllers module with a handle_receive method to pass a payload to a protocol.

Suitable protocol will be identified via protocol identify_payload methods.

federation/controllers.py

@@ -0,0 +1,23 @@
+import importlib
+
+from federation.exceptions import NoSuitableProtocolFoundError
+
+
+PROTOCOLS = (
+    "diaspora",
+)
+
+
+def handle_receive(payload, user=None):
+    """Takes a payload and passes it to the correct protocol."""
+    protocol = None
+    for protocol_name in PROTOCOLS:
+        protocol = importlib.import_module("federation.protocols.%s.protocol" % protocol_name)
+        if protocol.identify_payload(payload):
+            break
+
+    if protocol:
+        proto_obj = protocol.Protocol()
+        return proto_obj.receive(payload, user)
+    else:
+        raise NoSuitableProtocolFoundError()

federation/exceptions.py

@@ -1,5 +1,3 @@
-
-
 class EncryptedMessageError(Exception):
     pass
 
@@ -10,3 +8,7 @@ class NoHeaderInMessageError(Exception):
 
 class NoSenderKeyFoundError(Exception):
     pass
+
+
+class NoSuitableProtocolFoundError(Exception):
+    pass

federation/protocols/base.py

@@ -1,6 +1,18 @@
 import logging
 
 
+def identify_payload(payload):
+    """Each protocol module should define an 'identify_payload' method.
+
+    Args:
+        payload (str) - Payload blob
+
+    Returns:
+        True or False - A boolean whether the payload matches this protocol.
+    """
+    raise NotImplementedError("Implement in protocol module")
+
+
 class BaseProtocol(object):
 
     # Should be implemented by subclasses

federation/protocols/diaspora/protocol.py

@@ -12,7 +12,15 @@ from federation.exceptions import EncryptedMessageError, NoHeaderInMessageError,
 from federation.protocols.base import BaseProtocol
 
 
-class DiasporaProtocol(BaseProtocol):
+def identify_payload(payload):
+    try:
+        xml = unquote_plus(payload)
+        return xml.find(identify_str = '<diaspora xmlns="%s"' % Protocol.protocol_ns) > -1
+    except Exception:
+        return False
+
+
+class Protocol(BaseProtocol):
     """Diaspora protocol parts
 
     Mostly taken from Pyaspora (https://github.com/lukeross/pyaspora).
@@ -22,7 +30,7 @@ class DiasporaProtocol(BaseProtocol):
     user_agent = 'social-federation/diaspora/0.1'
 
     def __init__(self, contact_key_fetcher=None, *args, **kwargs):
-        super(DiasporaProtocol, self).__init__()
+        super(Protocol, self).__init__()
         self.get_contact_key = contact_key_fetcher
 
     def receive(self, payload, user=None, *args, **kwargs):

federation/tests/protocols/diaspora/test_diaspora.py

@@ -1,9 +1,9 @@
 from base64 import urlsafe_b64decode
 from lxml import etree
 import pytest
-from federation.exceptions import EncryptedMessageError, NoSenderKeyFoundError
 
-from federation.protocols.diaspora.protocol import DiasporaProtocol
+from federation.exceptions import EncryptedMessageError, NoSenderKeyFoundError
+from federation.protocols.diaspora.protocol import Protocol
 
 
 UNENCRYPTED_DOCUMENT = """<?xml version='1.0'?>
@@ -97,7 +97,7 @@ class TestDiasporaProtocol():
         assert body == urlsafe_b64decode("{data}".encode("ascii"))
 
     def init_protocol(self, contact_key_fetcher=None):
-        return DiasporaProtocol(contact_key_fetcher=contact_key_fetcher)
+        return Protocol(contact_key_fetcher=contact_key_fetcher)
 
     def get_unencrypted_doc(self):
         return etree.fromstring(UNENCRYPTED_DOCUMENT)