Merge pull request #415 from dairiki/feature.schema_node

Support passing colander schema nodes (instances)

CHANGES.txt

@@ -11,6 +11,19 @@ CHANGELOG
 2.0.3 (unreleased)
 ==================
 
+**Enhancements**
+
+- ``Cornice.validators.colander_validator`` and
+  ``cornice.validators.colander_body_validator`` now accept colander
+  schema node instances.  Previously only schema classes were
+  accepted.  For some discussion see #412.
+
+**Deprecations**
+
+- Passing schema classes to ``Cornice.validators.colander_validator`` and
+  ``cornice.validators.colander_body_validator`` is now deprecated.
+  (See above.)
+
 **Bug fixes**
 
 - To maintain consistency with cornice 1.2 as to the semantics of

cornice/validators/_colander.py

@@ -2,6 +2,9 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this file,
 # You can obtain one at http://mozilla.org/MPL/2.0/.
 
+import inspect
+import warnings
+
 
 def body_validator(request, schema=None, deserializer=None, **kwargs):
     """
@@ -17,20 +20,20 @@ def body_validator(request, schema=None, deserializer=None, **kwargs):
     :param request: Current request
     :type request: :class:`~pyramid:pyramid.request.Request`
 
-    :param schema: The Colander schema class
+    :param schema: The Colander schema
     :param deserializer: Optional deserializer, defaults to
         :func:`cornice.validators.extract_cstruct`
     """
     import colander
 
     if schema is not None:
         class RequestSchema(colander.MappingSchema):
-            body = schema()
+            body = _ensure_instantiated(schema)
 
             def deserialize(self, cstruct=colander.null):
                 appstruct = super(RequestSchema, self).deserialize(cstruct)
                 return appstruct['body']
-        schema = RequestSchema
+        schema = RequestSchema()
     return validator(request, schema, deserializer, **kwargs)
 
 
@@ -49,7 +52,7 @@ def validator(request, schema=None, deserializer=None, **kwargs):
     :param request: Current request
     :type request: :class:`~pyramid:pyramid.request.Request`
 
-    :param schema: The Colander schema class
+    :param schema: The Colander schema
     :param deserializer: Optional deserializer, defaults to
         :func:`cornice.validators.extract_cstruct`
     """
@@ -62,7 +65,7 @@ def validator(request, schema=None, deserializer=None, **kwargs):
     if schema is None:
         raise TypeError('This validator cannot work without a schema')
 
-    schema = schema()
+    schema = _ensure_instantiated(schema)
     cstruct = deserializer(request)
     try:
         deserialized = schema.deserialize(cstruct)
@@ -81,3 +84,14 @@ def validator(request, schema=None, deserializer=None, **kwargs):
                 field = prefixed[1]
 
             request.errors.add(location, field, error_dict[name])
+
+
+def _ensure_instantiated(schema):
+    if inspect.isclass(schema):
+        warnings.warn(
+            "Setting schema to a class is deprecated. "
+            " Set schema to an instance instead.",
+            DeprecationWarning,
+            stacklevel=2)
+        schema = schema()
+    return schema

docs/source/schema.rst

@@ -59,7 +59,7 @@ To describe a schema, using Colander and Cornice, here is how you can do:
     class SignupSchema(colander.MappingSchema):
         username = colander.SchemaNode(colander.String())
 
-    @signup.post(schema=SignupSchema, validators=(colander_body_validator,))
+    @signup.post(schema=SignupSchema(), validators=(colander_body_validator,))
     def signup_post(request):
         username = request.validated['username']
         return {'success': True}
@@ -120,7 +120,7 @@ The ``request.validated`` hences reflects this additional level.
 
     signup = cornice.Service()
 
-    @signup.post(schema=SignupSchema, validators=(colander_validator,))
+    @signup.post(schema=SignupSchema(), validators=(colander_validator,))
     def signup_post(request):
         username = request.validated['body']['username']
         referrer = request.validated['querystring']['referrer']
@@ -161,7 +161,7 @@ The general pattern in this case is:
         return extract_data_somehow(request)
 
 
-    @service.post(schema=MySchema,
+    @service.post(schema=MySchema(),
                   deserializer=my_deserializer,
                   validators=(colander_body_validator,))
     def post(request):

docs/source/upgrading.rst

@@ -88,7 +88,7 @@ Now:
     class SignupSchema(colander.MappingSchema):
         username = colander.SchemaNode(colander.String())
 
-    @signup.post(schema=SignupSchema, validators=(colander_body_validator,))
+    @signup.post(schema=SignupSchema(), validators=(colander_body_validator,))
     def signup_postt(request):
         username = request.validated['username']
         return {'success': True}
@@ -145,7 +145,7 @@ Now:
 
     signup = cornice.Service()
 
-    @signup.post(schema=SignupSchema, validators=(colander_validator,))
+    @signup.post(schema=SignupSchema(), validators=(colander_validator,))
     def signup_post(request):
         username = request.validated['body']['username']
         referrer = request.validated['querystring']['referrer']
@@ -207,7 +207,7 @@ Deserializers are still defined via the same API:
             return dict(zip(['foo', 'bar', 'yeah'], values))
         request.errors.add(location='body', description='Unsupported content')
 
-    @myservice.post(schema=FooBarSchema,
+    @myservice.post(schema=FooBarSchema(),
                     deserializer=dummy_deserializer,
                     validators=(my_validator,))
 

tests/test_colander.py

@@ -2,6 +2,7 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this file,
 # You can obtain one at http://mozilla.org/MPL/2.0/.
 import json
+import warnings
 
 from cornice.errors import Errors
 from cornice.validators._colander import validator
@@ -66,11 +67,36 @@ def __init__(self, body, json_body, get, method='GET'):
         return dummy_request
 
     class TestSchemas(TestCase):
-        def test_body_contains_fields(self):
+        def test_validation(self):
             body = {'bar': '1',
-                    'baz': 2,
+                    'baz': '2',
                     'foo': 'yeah'}
-            headers = {'x-foo': 'version_a'}
+            request = get_mock_request(body)
+            validator(request, schema=RequestSchema())
+            self.assertEqual(len(request.errors), 0)
+            self.assertEqual(request.validated['body'], {
+                'foo': 'yeah',
+                'bar': '1',
+                'baz': 2,
+                })
 
-            dummy_request = get_mock_request(body, headers=headers)
-            validator(dummy_request, schema=RequestSchema)
+        def test_validation_failure(self):
+            body = {'bar': '1',
+                    'baz': 'two',
+                    'foo': 'yeah'}
+            request = get_mock_request(body)
+            validator(request, schema=RequestSchema())
+            self.assertEqual(len(request.errors), 1)
+            self.assertEqual(request.validated, {})
+            error = request.errors[0]
+            self.assertEqual(error['location'], 'body')
+            self.assertEqual(error['name'], 'baz')
+
+        def test_schema_class_deprecated(self):
+            body = {}
+            request = get_mock_request(body)
+            with warnings.catch_warnings(record=True) as w:
+                warnings.resetwarnings()
+                validator(request, schema=RequestSchema)
+            self.assertEqual(len(w), 1)
+            self.assertIs(w[0].category, DeprecationWarning)

tests/validationapp.py

@@ -170,7 +170,7 @@ def post7(request):
     class SignupSchema(MappingSchema):
         username = SchemaNode(String())
 
-    @signup.post(schema=SignupSchema, validators=(colander_body_validator,))
+    @signup.post(schema=SignupSchema(), validators=(colander_body_validator,))
     def signup_post(request):
         return request.validated
 
@@ -206,7 +206,7 @@ def deserialize(self, cstruct):
 
     foobar = Service(name="foobar", path="/foobar")
 
-    @foobar.post(schema=RequestSchema, validators=(colander_validator,))
+    @foobar.post(schema=RequestSchema(), validators=(colander_validator,))
     def foobar_post(request):
         return {"test": "succeeded"}
 
@@ -226,7 +226,7 @@ class QSSchema(MappingSchema):
 
     foobaz = Service(name="foobaz", path="/foobaz")
 
-    @foobaz.get(schema=QSSchema, validators=(colander_validator,))
+    @foobaz.get(schema=QSSchema(), validators=(colander_validator,))
     def foobaz_get(request):
         return {"field": request.validated['querystring']['field']}
 
@@ -250,7 +250,7 @@ def deserialize(self, cstruct=null):
 
     email_service = Service(name='newsletter', path='/newsletter')
 
-    @email_service.post(schema=NewsletterPayload,
+    @email_service.post(schema=NewsletterPayload(),
                         validators=(colander_validator,))
     def newsletter(request):
         return request.validated
@@ -263,7 +263,7 @@ class ItemSchema(MappingSchema):
 
     item_service = Service(name='item', path='/item/{item_id}')
 
-    @item_service.get(schema=ItemSchema,
+    @item_service.get(schema=ItemSchema(),
                       validators=(colander_validator,))
     def item(request):
         return request.validated['path']