Merge pull request #73 from Tarsbot/master

if output is empty, auto return the error 404.

tests/func_test.py

@@ -66,12 +66,43 @@ def post(self):
         return "Fission mailed."
 
 
+class NotFoundHandler(requesthandlers.APIHandler):
+
+    @schema.validate(**{
+        "output_schema": {
+            "type": "number",
+        },
+        "on_empty_404": True
+    })
+    def get(self):
+        """This handler is used for testing empty output."""
+        return 0
+
+    @schema.validate(**{
+        "input_schema": {
+            "type": "number",
+        },
+        "output_schema": {
+            "type": "object",
+            "properties": {
+                "name": {"type": "string"}
+            },
+            "required": ["name", ]
+        },
+        "on_empty_404": False
+    })
+    def post(self):
+        """This handler is used for testing empty json output."""
+        return {}
+
+
 class APIFunctionalTest(AsyncHTTPTestCase):
 
     def get_app(self):
         rts = routes.get_routes(helloworld)
         rts += [
             ("/api/explodinghandler", ExplodingHandler),
+            ("/api/notfoundhandler", NotFoundHandler),
             ("/views/someview", DummyView),
             ("/api/dbtest", DBTestHandler)
         ]
@@ -149,6 +180,28 @@ def test_write_error(self):
             "fail"
         )
 
+    def test_empty_resource(self):
+        # Test empty output
+        r = self.fetch(
+            "/api/notfoundhandler"
+        )
+        self.assertEqual(r.code, 404)
+        self.assertEqual(
+            jl(r.body)["status"],
+            "fail"
+        )
+        # Test empty output on_empty_404 is False
+        r = self.fetch(
+            "/api/notfoundhandler",
+            method="POST",
+            body="1"
+        )
+        self.assertEqual(r.code, 500)
+        self.assertEqual(
+            jl(r.body)["status"],
+            "error"
+        )
+
     def test_view_db_conn(self):
         r = self.fetch(
             "/views/someview",

tornado_json/schema.py

@@ -3,6 +3,9 @@
 
 import jsonschema
 import tornado.gen
+
+from tornado_json.exceptions import APIError
+
 try:
     from tornado.concurrent import is_future
 except ImportError:
@@ -15,10 +18,13 @@
 
 def validate(input_schema=None, output_schema=None,
              input_example=None, output_example=None,
-             format_checker=None):
+             format_checker=None, on_empty_404=False):
     """Parameterized decorator for schema validation
 
     :type format_checker: jsonschema.FormatChecker or None
+    :type on_empty_404: bool
+    :param on_empty_404: If this is set, and the result from the
+        decorated method is a falsy value, a 404 will be raised.
     """
     @container
     def _validate(rh_method):
@@ -38,6 +44,8 @@ def _validate(rh_method):
             or malformed
         :raises TypeError: If the output is invalid as per the schema
             or malformed
+        :raises APIError: If the output is a falsy value and
+            on_empty_404 is True, an HTTP 404 error is returned
         """
         @wraps(rh_method)
         @tornado.gen.coroutine
@@ -76,6 +84,10 @@ def _wrapper(self, *args, **kwargs):
             if is_future(output):
                 output = yield output
 
+            # if output is empty, auto return the error 404.
+            if not output and on_empty_404:
+                raise APIError(404, "Resource not found.")
+
             if output_schema is not None:
                 # We wrap output in an object before validating in case
                 #  output is a string (and ergo not a validatable JSON object)