Make webhooks as separate modules with view and tests.

Create python packege for every webhook with view.py and tests.py

zerver/webhooks/trello/__init__.py

@@ -0,0 +1,38 @@
+# Webhooks for external integrations.
+from __future__ import absolute_import
+import ujson
+from typing import Mapping, Any, Tuple, Text
+from django.utils.translation import ugettext as _
+from django.http import HttpRequest, HttpResponse
+from zerver.lib.actions import check_send_message
+from zerver.decorator import return_success_on_head_request
+from zerver.lib.response import json_success, json_error
+from zerver.models import UserProfile, Client
+from zerver.decorator import REQ, has_request_variables, api_key_only_webhook_view
+
+from .view.card_actions import SUPPORTED_CARD_ACTIONS, process_card_action
+from .view.board_actions import SUPPORTED_BOARD_ACTIONS, process_board_action
+from .view.exceptions import UnsupportedAction
+
+@api_key_only_webhook_view('Trello')
+@return_success_on_head_request
+@has_request_variables
+def api_trello_webhook(request, user_profile, client, payload=REQ(argument_type='body'), stream=REQ(default='trello')):
+    # type: (HttpRequest, UserProfile, Client, Mapping[str, Any], Text) -> HttpResponse
+    payload = ujson.loads(request.body)
+    action_type = payload.get('action').get('type')
+    try:
+        subject, body = get_subject_and_body(payload, action_type)
+    except UnsupportedAction:
+        return json_error(_('Unsupported action_type: {action_type}'.format(action_type=action_type)))
+
+    check_send_message(user_profile, client, 'stream', [stream], subject, body)
+    return json_success()
+
+def get_subject_and_body(payload, action_type):
+    # type: (Mapping[str, Any], Text) -> Tuple[Text, Text]
+    if action_type in SUPPORTED_CARD_ACTIONS:
+        return process_card_action(payload, action_type)
+    if action_type in SUPPORTED_BOARD_ACTIONS:
+        return process_board_action(payload, action_type)
+    raise UnsupportedAction('{} if not supported'.format(action_type))