Support for init_app

Fixes: #24

Author: sergioisidoro

github_webhook/webhook.py

@@ -16,11 +16,20 @@ class Webhook(object):
     :param secret: Optional secret, used to authenticate the hook comes from Github
     """
 
-    def __init__(self, app, endpoint="/postreceive", secret=None):
-        app.add_url_rule(rule=endpoint, endpoint=endpoint, view_func=self._postreceive, methods=["POST"])
+    def __init__(self, app=None, endpoint="/postreceive", secret=None):
+        self.app = app
+        self.set_secret(secret)
+        if app is not None:
+            self.init_app(app, endpoint, secret)
 
+    def init_app(self, app, endpoint="/postreceive", secret=None):
         self._hooks = collections.defaultdict(list)
         self._logger = logging.getLogger("webhook")
+        if secret is not None:
+            self.set_secret(secret)
+        app.add_url_rule(rule=endpoint, endpoint=endpoint, view_func=self._postreceive, methods=["POST"])
+
+    def set_secret(self, secret=None):
         if secret is not None and not isinstance(secret, six.binary_type):
             secret = secret.encode("utf-8")
         self._secret = secret

tests/test_webhook.py

@@ -65,6 +65,44 @@ def test_constructor():
     )
 
 
+def test_init_app_flow():
+    # GIVEN
+    app = mock.Mock()
+
+    # WHEN
+    webhook = Webhook()
+    webhook.init_app(app)
+
+    # THEN
+    app.add_url_rule.assert_called_once_with(
+        endpoint="/postreceive", rule="/postreceive", view_func=webhook._postreceive, methods=["POST"]
+    )
+
+
+def test_init_app_flow_should_not_accidentally_override_secrets():
+    # GIVEN
+    app = mock.Mock()
+
+    # WHEN
+    webhook = Webhook(secret="hello-world-of-secrecy")
+    webhook.init_app(app)
+
+    # THEN
+    assert webhook._secret is not None
+
+
+def test_init_app_flow_should_override_secrets():
+    # GIVEN
+    app = mock.Mock()
+
+    # WHEN
+    webhook = Webhook(secret="hello-world-of-secrecy")
+    webhook.init_app(app, secret="a-new-world-of-secrecy")
+
+    # THEN
+    assert webhook._secret == "a-new-world-of-secrecy".encode("utf-8")
+
+
 def test_run_push_hook(webhook, handler, push_request):
     # WHEN
     webhook._postreceive()