Subscription revamp (#1235)

* Integrate async tests into main code

* Added full support for subscriptions

* Fixed syntax using black

* Fixed typo

Makefile

@@ -8,7 +8,7 @@ install-dev:
 	pip install -e ".[dev]"
 
 test:
-	py.test graphene examples tests_asyncio
+	py.test graphene examples
 
 .PHONY: docs ## Generate docs
 docs: install-dev
@@ -20,8 +20,8 @@ docs-live: install-dev
 
 .PHONY: format
 format:
-	black graphene examples setup.py tests_asyncio
+	black graphene examples setup.py
 
 .PHONY: lint
 lint:
-	flake8 graphene examples setup.py tests_asyncio
+	flake8 graphene examples setup.py

graphene/relay/connection.py

@@ -171,8 +171,8 @@ def connection_resolver(cls, resolver, connection_type, root, info, **args):
         on_resolve = partial(cls.resolve_connection, connection_type, args)
         return maybe_thenable(resolved, on_resolve)
 
-    def get_resolver(self, parent_resolver):
-        resolver = super(IterableConnectionField, self).get_resolver(parent_resolver)
+    def wrap_resolve(self, parent_resolver):
+        resolver = super(IterableConnectionField, self).wrap_resolve(parent_resolver)
         return partial(self.connection_resolver, resolver, self.type)
 
 

graphene/relay/node.py

@@ -37,7 +37,7 @@ def id_resolver(parent_resolver, node, root, info, parent_type_name=None, **args
         parent_type_name = parent_type_name or info.parent_type.name
         return node.to_global_id(parent_type_name, type_id)  # root._meta.name
 
-    def get_resolver(self, parent_resolver):
+    def wrap_resolve(self, parent_resolver):
         return partial(
             self.id_resolver,
             parent_resolver,
@@ -60,7 +60,7 @@ def __init__(self, node, type_=False, **kwargs):
             **kwargs,
         )
 
-    def get_resolver(self, parent_resolver):
+    def wrap_resolve(self, parent_resolver):
         return partial(self.node_type.node_resolver, get_type(self.field_type))
 
 

graphene/relay/tests/test_global_id.py

@@ -45,14 +45,14 @@ def test_global_id_allows_overriding_of_node_and_required():
 def test_global_id_defaults_to_info_parent_type():
     my_id = "1"
     gid = GlobalID()
-    id_resolver = gid.get_resolver(lambda *_: my_id)
+    id_resolver = gid.wrap_resolve(lambda *_: my_id)
     my_global_id = id_resolver(None, Info(User))
     assert my_global_id == to_global_id(User._meta.name, my_id)
 
 
 def test_global_id_allows_setting_customer_parent_type():
     my_id = "1"
     gid = GlobalID(parent_type=User)
-    id_resolver = gid.get_resolver(lambda *_: my_id)
+    id_resolver = gid.wrap_resolve(lambda *_: my_id)
     my_global_id = id_resolver(None, None)
     assert my_global_id == to_global_id(User._meta.name, my_id)

graphene/types/field.py

@@ -8,6 +8,7 @@
 from .structures import NonNull
 from .unmountedtype import UnmountedType
 from .utils import get_type
+from ..utils.deprecated import warn_deprecation
 
 base_type = type
 
@@ -114,5 +115,24 @@ def __init__(
     def type(self):
         return get_type(self._type)
 
-    def get_resolver(self, parent_resolver):
+    get_resolver = None
+
+    def wrap_resolve(self, parent_resolver):
+        """
+        Wraps a function resolver, using the ObjectType resolve_{FIELD_NAME}
+        (parent_resolver) if the Field definition has no resolver.
+        """
+        if self.get_resolver is not None:
+            warn_deprecation(
+                "The get_resolver method is being deprecated, please rename it to wrap_resolve."
+            )
+            return self.get_resolver(parent_resolver)
+
         return self.resolver or parent_resolver
+
+    def wrap_subscribe(self, parent_subscribe):
+        """
+        Wraps a function subscribe, using the ObjectType subscribe_{FIELD_NAME}
+        (parent_subscribe) if the Field definition has no subscribe.
+        """
+        return parent_subscribe

graphene/types/schema.py

@@ -10,8 +10,11 @@
     parse,
     print_schema,
     subscribe,
+    validate,
+    ExecutionResult,
     GraphQLArgument,
     GraphQLBoolean,
+    GraphQLError,
     GraphQLEnumValue,
     GraphQLField,
     GraphQLFloat,
@@ -76,6 +79,11 @@ def is_type_of_from_possible_types(possible_types, root, _info):
     return isinstance(root, possible_types)
 
 
+# We use this resolver for subscriptions
+def identity_resolve(root, info):
+    return root
+
+
 class TypeMap(dict):
     def __init__(
         self,
@@ -307,30 +315,48 @@ def create_fields_for_type(self, graphene_type, is_input_type=False):
                         if isinstance(arg.type, NonNull)
                         else arg.default_value,
                     )
+                subscribe = field.wrap_subscribe(
+                    self.get_function_for_type(
+                        graphene_type, f"subscribe_{name}", name, field.default_value,
+                    )
+                )
+
+                # If we are in a subscription, we use (by default) an
+                # identity-based resolver for the root, rather than the
+                # default resolver for objects/dicts.
+                if subscribe:
+                    field_default_resolver = identity_resolve
+                elif issubclass(graphene_type, ObjectType):
+                    default_resolver = (
+                        graphene_type._meta.default_resolver or get_default_resolver()
+                    )
+                    field_default_resolver = partial(
+                        default_resolver, name, field.default_value
+                    )
+                else:
+                    field_default_resolver = None
+
+                resolve = field.wrap_resolve(
+                    self.get_function_for_type(
+                        graphene_type, f"resolve_{name}", name, field.default_value
+                    )
+                    or field_default_resolver
+                )
+
                 _field = GraphQLField(
                     field_type,
                     args=args,
-                    resolve=field.get_resolver(
-                        self.get_resolver_for_type(
-                            graphene_type, f"resolve_{name}", name, field.default_value
-                        )
-                    ),
-                    subscribe=field.get_resolver(
-                        self.get_resolver_for_type(
-                            graphene_type,
-                            f"subscribe_{name}",
-                            name,
-                            field.default_value,
-                        )
-                    ),
+                    resolve=resolve,
+                    subscribe=subscribe,
                     deprecation_reason=field.deprecation_reason,
                     description=field.description,
                 )
             field_name = field.name or self.get_name(name)
             fields[field_name] = _field
         return fields
 
-    def get_resolver_for_type(self, graphene_type, func_name, name, default_value):
+    def get_function_for_type(self, graphene_type, func_name, name, default_value):
+        """Gets a resolve or subscribe function for a given ObjectType"""
         if not issubclass(graphene_type, ObjectType):
             return
         resolver = getattr(graphene_type, func_name, None)
@@ -350,11 +376,6 @@ def get_resolver_for_type(self, graphene_type, func_name, name, default_value):
         if resolver:
             return get_unbound_function(resolver)
 
-        default_resolver = (
-            graphene_type._meta.default_resolver or get_default_resolver()
-        )
-        return partial(default_resolver, name, default_value)
-
     def resolve_type(self, resolve_type_func, type_name, root, info, _type):
         type_ = resolve_type_func(root, info)
 
@@ -476,7 +497,19 @@ async def execute_async(self, *args, **kwargs):
         return await graphql(self.graphql_schema, *args, **kwargs)
 
     async def subscribe(self, query, *args, **kwargs):
-        document = parse(query)
+        """Execute a GraphQL subscription on the schema asynchronously."""
+        # Do parsing
+        try:
+            document = parse(query)
+        except GraphQLError as error:
+            return ExecutionResult(data=None, errors=[error])
+
+        # Do validation
+        validation_errors = validate(self.graphql_schema, document)
+        if validation_errors:
+            return ExecutionResult(data=None, errors=validation_errors)
+
+        # Execute the query
         kwargs = normalize_execute_kwargs(kwargs)
         return await subscribe(self.graphql_schema, document, *args, **kwargs)
 

graphene/types/tests/test_subscribe_async.py

@@ -0,0 +1,56 @@
+from pytest import mark
+
+from graphene import ObjectType, Int, String, Schema, Field
+
+
+class Query(ObjectType):
+    hello = String()
+
+    def resolve_hello(root, info):
+        return "Hello, world!"
+
+
+class Subscription(ObjectType):
+    count_to_ten = Field(Int)
+
+    async def subscribe_count_to_ten(root, info):
+        count = 0
+        while count < 10:
+            count += 1
+            yield count
+
+
+schema = Schema(query=Query, subscription=Subscription)
+
+
+@mark.asyncio
+async def test_subscription():
+    subscription = "subscription { countToTen }"
+    result = await schema.subscribe(subscription)
+    count = 0
+    async for item in result:
+        count = item.data["countToTen"]
+    assert count == 10
+
+
+@mark.asyncio
+async def test_subscription_fails_with_invalid_query():
+    # It fails if the provided query is invalid
+    subscription = "subscription { "
+    result = await schema.subscribe(subscription)
+    assert not result.data
+    assert result.errors
+    assert "Syntax Error: Expected Name, found <EOF>" in str(result.errors[0])
+
+
+@mark.asyncio
+async def test_subscription_fails_when_query_is_not_valid():
+    # It can't subscribe to two fields at the same time, triggering a
+    # validation error.
+    subscription = "subscription { countToTen, b: countToTen }"
+    result = await schema.subscribe(subscription)
+    assert not result.data
+    assert result.errors
+    assert "Anonymous Subscription must select only one top level field." in str(
+        result.errors[0]
+    )

tox.ini

@@ -8,7 +8,7 @@ deps =
 setenv =
      PYTHONPATH = .:{envdir}
 commands =
-    py{36,37}: pytest --cov=graphene graphene examples tests_asyncio {posargs}
+    py{36,37}: pytest --cov=graphene graphene examples {posargs}
 
 [testenv:pre-commit]
 basepython=python3.7