Move handle_send protocol identification to federation module root

Add also "identify by id" function.

federation/__init__.py

@@ -1 +1,30 @@
+import importlib
+
+from federation.exceptions import NoSuitableProtocolFoundError
+
 __version__ = "0.18.0-dev"
+
+PROTOCOLS = (
+    "activitypub",
+    "diaspora",
+)
+
+
+def identify_protocol(method: str, value: str):
+    """
+    Loop through protocols, import the protocol module and try to identify the id or payload.
+    """
+    for protocol_name in PROTOCOLS:
+        protocol = importlib.import_module(f"federation.protocols.{protocol_name}.protocol")
+        if getattr(protocol, f"identify_{method}")(value):
+            return protocol
+    else:
+        raise NoSuitableProtocolFoundError()
+
+
+def identify_protocol_by_id(id: str):
+    return identify_protocol('id', id)
+
+
+def identify_protocol_by_payload(payload: str):
+    return identify_protocol('payload', payload)

federation/inbound.py

@@ -2,16 +2,11 @@ import importlib
 import logging
 from typing import Tuple, List, Callable
 
-from federation.exceptions import NoSuitableProtocolFoundError
+from federation import identify_protocol_by_payload
 from federation.types import UserType
 
 logger = logging.getLogger("federation")
 
-PROTOCOLS = (
-    "activitypub",
-    "diaspora",
-)
-
 
 def handle_receive(
         payload: str,
@@ -36,24 +31,15 @@ def handle_receive(
     :arg sender_key_fetcher: Function that accepts sender handle and returns public key (optional)
     :arg skip_author_verification: Don't verify sender (test purposes, false default)
     :returns: Tuple of sender id, protocol name and list of entity objects
-    :raises NoSuitableProtocolFound: When no protocol was identified to pass message to
     """
     logger.debug("handle_receive: processing payload: %s", payload)
-    found_protocol = None
-    for protocol_name in PROTOCOLS:
-        protocol = importlib.import_module("federation.protocols.%s.protocol" % protocol_name)
-        if protocol.identify_payload(payload):
-            found_protocol = protocol
-            break
+    found_protocol = identify_protocol_by_payload(payload)
 
-    if found_protocol:
-        logger.debug("handle_receive: using protocol %s", found_protocol.PROTOCOL_NAME)
-        protocol = found_protocol.Protocol()
-        sender, message = protocol.receive(
-            payload, user, sender_key_fetcher, skip_author_verification=skip_author_verification)
-        logger.debug("handle_receive: sender %s, message %s", sender, message)
-    else:
-        raise NoSuitableProtocolFoundError()
+    logger.debug("handle_receive: using protocol %s", found_protocol.PROTOCOL_NAME)
+    protocol = found_protocol.Protocol()
+    sender, message = protocol.receive(
+        payload, user, sender_key_fetcher, skip_author_verification=skip_author_verification)
+    logger.debug("handle_receive: sender %s, message %s", sender, message)
 
     mappers = importlib.import_module("federation.entities.%s.mappers" % found_protocol.PROTOCOL_NAME)
     entities = mappers.message_to_objects(message, sender, sender_key_fetcher, user)

federation/protocols/diaspora/protocol.py

@@ -13,7 +13,7 @@ from federation.protocols.diaspora.encrypted import EncryptedPayload
 from federation.protocols.diaspora.magic_envelope import MagicEnvelope
 from federation.types import UserType
 from federation.utils.diaspora import fetch_public_key
-from federation.utils.text import decode_if_bytes, encode_if_text
+from federation.utils.text import decode_if_bytes, encode_if_text, validate_handle
 
 logger = logging.getLogger("federation")
 
@@ -22,6 +22,13 @@ PROTOCOL_NS = "https://joindiaspora.com/protocol"
 MAGIC_ENV_TAG = "{http://salmon-protocol.org/ns/magic-env}env"
 
 
+def identify_id(id: str) -> bool:
+    """
+    Try to identify if this ID is a Diaspora ID.
+    """
+    return validate_handle(id)
+
+
 def identify_payload(payload):
     """Try to identify whether this is a Diaspora payload.
 

federation/tests/test_inbound.py

@@ -8,7 +8,7 @@ from federation.protocols.diaspora.protocol import Protocol
 from federation.tests.fixtures.payloads import DIASPORA_PUBLIC_PAYLOAD
 
 
-class TestHandleReceiveProtocolIdentification():
+class TestHandleReceiveProtocolIdentification:
     def test_handle_receive_routes_to_identified_protocol(self):
         payload = DIASPORA_PUBLIC_PAYLOAD
         with patch.object(