Merge pull request #162 from lichray/default_options

feat(api): default responder for OPTIONS method

Closes issue #68

falcon/api_helpers.py

@@ -203,6 +203,14 @@ def create_http_method_map(resource, uri_fields, before, after):
 
     # Attach a resource for unsupported HTTP methods
     allowed_methods = sorted(list(method_map.keys()))
+
+    if 'OPTIONS' not in method_map:
+        # OPTIONS itself is intentionally excluded from the Allow header
+        # This default responder does not run the hooks
+        method_map['OPTIONS'] = responders.create_default_options(
+            allowed_methods)
+        allowed_methods.append('OPTIONS')
+
     na_responder = responders.create_method_not_allowed(allowed_methods)
 
     for method in HTTP_METHODS:

falcon/responders.py

@@ -16,6 +16,7 @@ limitations under the License.
 
 """
 
+from falcon.status_codes import HTTP_204
 from falcon.status_codes import HTTP_400
 from falcon.status_codes import HTTP_404
 from falcon.status_codes import HTTP_405
@@ -45,9 +46,27 @@ def create_method_not_allowed(allowed_methods):
             returned in the Allow header.
 
     """
+    allowed = ', '.join(allowed_methods)
 
     def method_not_allowed(req, resp, **kwargs):
         resp.status = HTTP_405
-        resp.set_header('Allow', ', '.join(allowed_methods))
+        resp.set_header('Allow', allowed)
 
     return method_not_allowed
+
+
+def create_default_options(allowed_methods):
+    """Creates a default responder for the OPTIONS method
+
+    Args:
+        allowed_methods: A list of HTTP methods (uppercase) that should be
+            returned in the Allow header.
+
+    """
+    allowed = ', '.join(allowed_methods)
+
+    def on_options(req, resp, **kwargs):
+        resp.status = HTTP_204
+        resp.set_header('Allow', allowed)
+
+    return on_options

falcon/tests/test_after_hooks.py

@@ -66,6 +66,12 @@ class ZooResource(object):
         self.resp = resp
 
 
+class SingleResource(object):
+
+    def on_options(self, req, resp):
+        resp.status = falcon.HTTP_501
+
+
 class TestHooks(testing.TestBase):
 
     def before(self):
@@ -87,6 +93,11 @@ class TestHooks(testing.TestBase):
         self.simulate_request(self.test_route)
         self.assertEqual(b'fluffy', zoo_resource.resp.body_encoded)
 
+        # hook does not affect the default on_options
+        body = self.simulate_request(self.test_route, method='OPTIONS')
+        self.assertEqual(falcon.HTTP_204, self.srmock.status)
+        self.assertEqual([], body)
+
     def test_multiple_global_hook(self):
         self.api = falcon.API(after=[fluffiness, cuteness])
         zoo_resource = ZooResource()
@@ -122,3 +133,18 @@ class TestHooks(testing.TestBase):
 
         self.simulate_request('/wrapped', method='PATCH')
         self.assertEqual(falcon.HTTP_405, self.srmock.status)
+
+        # decorator does not affect the default on_options
+        body = self.simulate_request('/wrapped', method='OPTIONS')
+        self.assertEqual(falcon.HTTP_204, self.srmock.status)
+        self.assertEqual([], body)
+
+    def test_customized_options(self):
+        self.api = falcon.API(after=fluffiness)
+
+        self.api.add_route('/one', SingleResource())
+
+        body = self.simulate_request('/one', method='OPTIONS')
+        self.assertEqual(falcon.HTTP_501, self.srmock.status)
+        self.assertEqual([b'fluffy'], body)
+        self.assertNotIn('Allow', self.srmock.headers_dict)

falcon/tests/test_http_method_routing.py

@@ -160,7 +160,7 @@ class TestHttpMethodRouting(testing.TestBase):
 
     def test_methods_not_allowed_complex(self):
         for method in HTTP_METHODS:
-            if method in ('GET', 'POST', 'HEAD'):
+            if method in ('GET', 'POST', 'HEAD', 'OPTIONS'):
                 continue
 
             self.resource_things.called = False
@@ -170,13 +170,13 @@ class TestHttpMethodRouting(testing.TestBase):
             self.assertEquals(self.srmock.status, falcon.HTTP_405)
 
             headers = self.srmock.headers
-            allow_header = ('Allow', 'GET, HEAD, POST')
+            allow_header = ('Allow', 'GET, HEAD, POST, OPTIONS')
 
             self.assertThat(headers, Contains(allow_header))
 
     def test_method_not_allowed_with_param(self):
         for method in HTTP_METHODS:
-            if method == 'GET' or method == 'PUT':
+            if method in ('GET', 'PUT', 'OPTIONS'):
                 continue
 
             self.resource_get_with_faulty_put.called = False
@@ -187,10 +187,19 @@ class TestHttpMethodRouting(testing.TestBase):
             self.assertEquals(self.srmock.status, falcon.HTTP_405)
 
             headers = self.srmock.headers
-            allow_header = ('Allow', 'GET, PUT')
+            allow_header = ('Allow', 'GET, PUT, OPTIONS')
 
             self.assertThat(headers, Contains(allow_header))
 
+    def test_default_on_options(self):
+        self.simulate_request('/things/84/stuff/65', method='OPTIONS')
+        self.assertEquals(self.srmock.status, falcon.HTTP_204)
+
+        headers = self.srmock.headers
+        allow_header = ('Allow', 'GET, HEAD, POST')
+
+        self.assertThat(headers, Contains(allow_header))
+
     def test_unexpected_type_error(self):
         # Suppress logging
         stream = io.StringIO() if six.PY3 else io.BytesIO()