Add support for batching several requests into one

Batch format compatible with ReactRelayNetworkLayer (https://github.com/nodkz/react-relay-network-layer)

Author: michalochman

graphene_django/tests/test_views.py

@@ -8,20 +8,23 @@
     from urllib.parse import urlencode
 
 
-def url_string(**url_params):
-    string = '/graphql'
-
+def url_string(string='/graphql', **url_params):
     if url_params:
         string += '?' + urlencode(url_params)
 
     return string
 
 
+def batch_url_string(**url_params):
+    return url_string('/graphql/batch', **url_params)
+
+
 def response_json(response):
     return json.loads(response.content.decode())
 
 
 j = lambda **kwargs: json.dumps(kwargs)
+jl = lambda **kwargs: json.dumps([kwargs])
 
 
 def test_graphiql_is_enabled(client):
@@ -169,6 +172,17 @@ def test_allows_post_with_json_encoding(client):
     }
 
 
+def test_batch_allows_post_with_json_encoding(client):
+    response = client.post(batch_url_string(), jl(id=1, query='{test}'), 'application/json')
+
+    assert response.status_code == 200
+    assert response_json(response) == [{
+        'id': 1,
+        'payload': { 'data': {'test': "Hello World"} },
+        'status': 200,
+    }]
+
+
 def test_allows_sending_a_mutation_via_post(client):
     response = client.post(url_string(), j(query='mutation TestMutation { writeTest { test } }'), 'application/json')
 
@@ -199,6 +213,22 @@ def test_supports_post_json_query_with_string_variables(client):
     }
 
 
+
+def test_batch_supports_post_json_query_with_string_variables(client):
+    response = client.post(batch_url_string(), jl(
+        id=1,
+        query='query helloWho($who: String){ test(who: $who) }',
+        variables=json.dumps({'who': "Dolly"})
+    ), 'application/json')
+
+    assert response.status_code == 200
+    assert response_json(response) == [{
+        'id': 1,
+        'payload': { 'data': {'test': "Hello Dolly"} },
+        'status': 200,
+    }]
+
+
 def test_supports_post_json_query_with_json_variables(client):
     response = client.post(url_string(), j(
         query='query helloWho($who: String){ test(who: $who) }',
@@ -211,6 +241,21 @@ def test_supports_post_json_query_with_json_variables(client):
     }
 
 
+def test_batch_supports_post_json_query_with_json_variables(client):
+    response = client.post(batch_url_string(), jl(
+        id=1,
+        query='query helloWho($who: String){ test(who: $who) }',
+        variables={'who': "Dolly"}
+    ), 'application/json')
+
+    assert response.status_code == 200
+    assert response_json(response) == [{
+        'id': 1,
+        'payload': { 'data': {'test': "Hello Dolly"} },
+        'status': 200,
+    }]
+
+
 def test_supports_post_url_encoded_query_with_string_variables(client):
     response = client.post(url_string(), urlencode(dict(
         query='query helloWho($who: String){ test(who: $who) }',
@@ -285,6 +330,33 @@ def test_allows_post_with_operation_name(client):
     }
 
 
+def test_batch_allows_post_with_operation_name(client):
+    response = client.post(batch_url_string(), jl(
+        id=1,
+        query='''
+        query helloYou { test(who: "You"), ...shared }
+        query helloWorld { test(who: "World"), ...shared }
+        query helloDolly { test(who: "Dolly"), ...shared }
+        fragment shared on QueryRoot {
+          shared: test(who: "Everyone")
+        }
+        ''',
+        operationName='helloWorld'
+    ), 'application/json')
+
+    assert response.status_code == 200
+    assert response_json(response) == [{
+        'id': 1,
+        'payload': {
+            'data': {
+                'test': 'Hello World',
+                'shared': 'Hello Everyone'
+            }
+        },
+        'status': 200,
+    }]
+
+
 def test_allows_post_with_get_operation_name(client):
     response = client.post(url_string(
         operationName='helloWorld'

graphene_django/tests/urls.py

@@ -3,5 +3,6 @@
 from ..views import GraphQLView
 
 urlpatterns = [
+    url(r'^graphql/batch', GraphQLView.as_view(batch=True)),
     url(r'^graphql', GraphQLView.as_view(graphiql=True)),
 ]

graphene_django/views.py

@@ -62,8 +62,10 @@ class GraphQLView(View):
     middleware = None
     root_value = None
     pretty = False
+    batch = False
 
-    def __init__(self, schema=None, executor=None, middleware=None, root_value=None, graphiql=False, pretty=False):
+    def __init__(self, schema=None, executor=None, middleware=None, root_value=None, graphiql=False, pretty=False,
+                 batch=False):
         if not schema:
             schema = graphene_settings.SCHEMA
 
@@ -77,8 +79,10 @@ def __init__(self, schema=None, executor=None, middleware=None, root_value=None,
         self.root_value = root_value
         self.pretty = pretty
         self.graphiql = graphiql
+        self.batch = batch
 
         assert isinstance(self.schema, GraphQLSchema), 'A Schema is required to be provided to GraphQLView.'
+        assert not all((graphiql, batch)), 'Use either graphiql or batch processing'
 
     # noinspection PyUnusedLocal
     def get_root_value(self, request):
@@ -99,32 +103,12 @@ def dispatch(self, request, *args, **kwargs):
             data = self.parse_body(request)
             show_graphiql = self.graphiql and self.can_display_graphiql(request, data)
 
-            query, variables, operation_name = self.get_graphql_params(request, data)
-
-            execution_result = self.execute_graphql_request(
-                request,
-                data,
-                query,
-                variables,
-                operation_name,
-                show_graphiql
-            )
-
-            if execution_result:
-                response = {}
-
-                if execution_result.errors:
-                    response['errors'] = [self.format_error(e) for e in execution_result.errors]
-
-                if execution_result.invalid:
-                    status_code = 400
-                else:
-                    status_code = 200
-                    response['data'] = execution_result.data
-
-                result = self.json_encode(request, response, pretty=show_graphiql)
+            if self.batch:
+                responses = [self.get_response(request, entry) for entry in data]
+                result = '[{}]'.format(','.join([response[0] for response in responses]))
+                status_code = max(responses, key=lambda response: response[1])[1]
             else:
-                result = None
+                result, status_code = self.get_response(request, data, show_graphiql)
 
             if show_graphiql:
                 return self.render_graphiql(
@@ -150,6 +134,43 @@ def dispatch(self, request, *args, **kwargs):
             })
             return response
 
+    def get_response(self, request, data, show_graphiql=False):
+        query, variables, operation_name, id = self.get_graphql_params(request, data)
+
+        execution_result = self.execute_graphql_request(
+            request,
+            data,
+            query,
+            variables,
+            operation_name,
+            show_graphiql
+        )
+
+        if execution_result:
+            response = {}
+
+            if execution_result.errors:
+                response['errors'] = [self.format_error(e) for e in execution_result.errors]
+
+            if execution_result.invalid:
+                status_code = 400
+            else:
+                status_code = 200
+                response['data'] = execution_result.data
+
+            if self.batch:
+                response = {
+                    'id': id,
+                    'payload': response,
+                    'status': status_code,
+                }
+
+            result = self.json_encode(request, response, pretty=show_graphiql)
+        else:
+            result = None
+
+        return result, status_code
+
     def render_graphiql(self, request, **data):
         return render(request, self.graphiql_template, data)
 
@@ -170,7 +191,10 @@ def parse_body(self, request):
         elif content_type == 'application/json':
             try:
                 request_json = json.loads(request.body.decode('utf-8'))
-                assert isinstance(request_json, dict)
+                if self.batch:
+                    assert isinstance(request_json, list)
+                else:
+                    assert isinstance(request_json, dict)
                 return request_json
             except:
                 raise HttpError(HttpResponseBadRequest('POST body sent invalid JSON.'))
@@ -242,6 +266,7 @@ def request_wants_html(cls, request):
     def get_graphql_params(request, data):
         query = request.GET.get('query') or data.get('query')
         variables = request.GET.get('variables') or data.get('variables')
+        id = request.GET.get('id') or data.get('id')
 
         if variables and isinstance(variables, six.text_type):
             try:
@@ -251,7 +276,7 @@ def get_graphql_params(request, data):
 
         operation_name = request.GET.get('operationName') or data.get('operationName')
 
-        return query, variables, operation_name
+        return query, variables, operation_name, id
 
     @staticmethod
     def format_error(error):