feat: add support for async schema in flask

graphql_server/flask/graphqlview.py

@@ -1,12 +1,14 @@
+import asyncio
 import copy
 from collections.abc import MutableMapping
 from functools import partial
 from typing import List
 
-from flask import Response, render_template_string, request
+from flask import Response, current_app, render_template_string, request
 from flask.views import View
 from graphql import specified_rules
 from graphql.error import GraphQLError
+from graphql.pyutils import is_awaitable
 from graphql.type.schema import GraphQLSchema
 
 from graphql_server import (
@@ -25,6 +27,7 @@
     GraphiQLOptions,
     render_graphiql_sync,
 )
+from graphql_server.utils import wrap_in_async
 
 
 class GraphQLView(View):
@@ -41,6 +44,7 @@ class GraphQLView(View):
     execution_context_class = None
     batch = False
     jinja_env = None
+    enable_async = False
     subscriptions = None
     headers = None
     default_query = None
@@ -110,12 +114,29 @@ def dispatch_request(self):
                 batch_enabled=self.batch,
                 catch=catch,
                 # Execute options
+                run_sync=not self.enable_async,
                 root_value=self.get_root_value(),
                 context_value=self.get_context(),
                 middleware=self.get_middleware(),
                 validation_rules=self.get_validation_rules(),
                 execution_context_class=self.get_execution_context_class(),
             )
+
+            async def get_async_execution_results():
+                return await asyncio.gather(
+                    *(
+                        ex
+                        if ex is not None and is_awaitable(ex)
+                        else wrap_in_async(lambda: ex)()
+                        for ex in execution_results
+                    )
+                )
+
+            if self.enable_async:
+                execution_results = current_app.ensure_sync(
+                    get_async_execution_results
+                )()
+
             result, status_code = encode_execution_results(
                 execution_results,
                 is_batch=isinstance(data, list),

setup.py

@@ -27,6 +27,10 @@
     "flask>=1,<3",
 ]
 
+install_flask_async_requires = [
+    "flask[async]>=2,<3",
+]
+
 install_sanic_requires = [
     "sanic>=21.12,<23",
 ]
@@ -43,7 +47,7 @@
 
 install_all_requires = (
     install_requires
-    + install_flask_requires
+    + install_flask_async_requires
     + install_sanic_requires
     + install_webob_requires
     + install_aiohttp_requires

tests/flask/app.py

@@ -4,11 +4,13 @@
 from tests.flask.schema import Schema
 
 
-def create_app(path="/graphql", **kwargs):
+def create_app(path="/graphql", schema=Schema, **kwargs):
     server = Flask(__name__)
     server.debug = True
+    view_cls = GraphQLView
     server.add_url_rule(
-        path, view_func=GraphQLView.as_view("graphql", schema=Schema, **kwargs)
+        path,
+        view_func=view_cls.as_view("graphql", schema=schema, **kwargs),
     )
     return server
 

tests/flask/schema.py

@@ -1,3 +1,5 @@
+import asyncio
+
 from graphql.type.definition import (
     GraphQLArgument,
     GraphQLField,
@@ -49,3 +51,29 @@ def resolve_raises(*_):
 )
 
 Schema = GraphQLSchema(QueryRootType, MutationRootType)
+
+
+async def resolver_field_async_1(_obj, info):
+    await asyncio.sleep(0.001)
+    return "hey"
+
+
+async def resolver_field_async_2(_obj, info):
+    await asyncio.sleep(0.003)
+    return "hey2"
+
+
+def resolver_field_sync(_obj, info):
+    return "hey3"
+
+
+AsyncQueryType = GraphQLObjectType(
+    name="AsyncQueryType",
+    fields={
+        "a": GraphQLField(GraphQLString, resolve=resolver_field_async_1),
+        "b": GraphQLField(GraphQLString, resolve=resolver_field_async_2),
+        "c": GraphQLField(GraphQLString, resolve=resolver_field_sync),
+    },
+)
+
+AsyncSchema = GraphQLSchema(AsyncQueryType)

tests/flask/test_graphqlview.py

@@ -7,6 +7,7 @@
 
 from ..utils import RepeatExecutionContext
 from .app import create_app
+from .schema import AsyncSchema
 
 
 def url_string(app, **url_params):
@@ -574,3 +575,11 @@ def test_custom_execution_context_class(app, client):
 
     assert response.status_code == 200
     assert response_json(response) == {"data": {"test": "Hello WorldHello World"}}
+
+
+@pytest.mark.parametrize("app", [create_app(schema=AsyncSchema, enable_async=True)])
+def test_async_schema(app, client):
+    response = client.get(url_string(app, query="{a,b,c}"))
+
+    assert response.status_code == 200
+    assert response_json(response) == {"data": {"a": "hey", "b": "hey2", "c": "hey3"}}