Added RELAY_CONNECTION_MAX_LIMIT and RELAY_CONNECTION_ENFORCE_FIRST_OR_LAST settings

Relay connections will be limited to 100 records by default.

Author: syrusakbary

graphene_django/fields.py

@@ -6,6 +6,7 @@
 from graphene.relay import ConnectionField, PageInfo
 from graphql_relay.connection.arrayconnection import connection_from_list_slice
 
+from .settings import graphene_settings
 from .utils import DJANGO_FILTER_INSTALLED, maybe_queryset
 
 
@@ -30,6 +31,14 @@ class DjangoConnectionField(ConnectionField):
 
     def __init__(self, *args, **kwargs):
         self.on = kwargs.pop('on', False)
+        self.max_limit = kwargs.pop(
+            'max_limit',
+            graphene_settings.RELAY_CONNECTION_MAX_LIMIT
+        )
+        self.enforce_first_or_last = kwargs.pop(
+            'enforce_first_or_last',
+            graphene_settings.RELAY_CONNECTION_ENFORCE_FIRST_OR_LAST
+        )
         super(DjangoConnectionField, self).__init__(*args, **kwargs)
 
     @property
@@ -51,7 +60,29 @@ def merge_querysets(cls, default_queryset, queryset):
         return default_queryset & queryset
 
     @classmethod
-    def connection_resolver(cls, resolver, connection, default_manager, root, args, context, info):
+    def connection_resolver(cls, resolver, connection, default_manager, max_limit,
+                            enforce_first_or_last, root, args, context, info):
+        first = args.get('first')
+        last = args.get('last')
+
+        if enforce_first_or_last:
+            assert first or last, (
+                'You must provide a `first` or `last` value to properly paginate the `{}` connection.'
+            ).format(info.field_name)
+
+        if max_limit:
+            if first:
+                assert first <= max_limit, (
+                    'Requesting {} records on the `{}` connection exceeds the `first` limit of {} records.'
+                ).format(first, info.field_name, max_limit)
+                args['first'] = min(first, max_limit)
+
+            if last:
+                assert last <= max_limit, (
+                    'Requesting {} records on the `{}` connection exceeds the `last` limit of {} records.'
+                ).format(first, info.field_name, max_limit)
+                args['last'] = min(last, max_limit)
+
         iterable = resolver(root, args, context, info)
         if iterable is None:
             iterable = default_manager
@@ -78,7 +109,14 @@ def connection_resolver(cls, resolver, connection, default_manager, root, args,
         return connection
 
     def get_resolver(self, parent_resolver):
-        return partial(self.connection_resolver, parent_resolver, self.type, self.get_manager())
+        return partial(
+            self.connection_resolver,
+            parent_resolver,
+            self.type,
+            self.get_manager(),
+            self.max_limit,
+            self.enforce_first_or_last
+        )
 
 
 def get_connection_field(*args, **kwargs):

graphene_django/filter/fields.py

@@ -67,16 +67,35 @@ def merge_querysets(default_queryset, queryset):
         return queryset
 
     @classmethod
-    def connection_resolver(cls, resolver, connection, default_manager, filterset_class, filtering_args,
+    def connection_resolver(cls, resolver, connection, default_manager, max_limit,
+                            enforce_first_or_last, filterset_class, filtering_args,
                             root, args, context, info):
         filter_kwargs = {k: v for k, v in args.items() if k in filtering_args}
         qs = filterset_class(
             data=filter_kwargs,
             queryset=default_manager.get_queryset()
         ).qs
+
         return super(DjangoFilterConnectionField, cls).connection_resolver(
-            resolver, connection, qs, root, args, context, info)
+            resolver,
+            connection,
+            qs,
+            max_limit,
+            enforce_first_or_last,
+            root,
+            args,
+            context,
+            info
+        )
 
     def get_resolver(self, parent_resolver):
-        return partial(self.connection_resolver, parent_resolver, self.type, self.get_manager(),
-                       self.filterset_class, self.filtering_args)
+        return partial(
+            self.connection_resolver,
+            parent_resolver,
+            self.type,
+            self.get_manager(),
+            self.max_limit,
+            self.enforce_first_or_last,
+            self.filterset_class,
+            self.filtering_args
+        )

graphene_django/settings.py

@@ -30,6 +30,11 @@
     'SCHEMA_OUTPUT': 'schema.json',
     'SCHEMA_INDENT': None,
     'MIDDLEWARE': (),
+    # Set to True if the connection fields must have
+    # either the first or last argument
+    'RELAY_CONNECTION_ENFORCE_FIRST_OR_LAST': False,
+    # Max items returned in ConnectionFields / FilterConnectionFields
+    'RELAY_CONNECTION_MAX_LIMIT': 100,
 }
 
 if settings.DEBUG:

graphene_django/tests/test_query.py

@@ -12,6 +12,7 @@
 from ..compat import MissingType, JSONField
 from ..fields import DjangoConnectionField
 from ..types import DjangoObjectType
+from ..settings import graphene_settings
 from .models import Article, Reporter
 
 pytestmark = pytest.mark.django_db
@@ -452,3 +453,95 @@ class Query(graphene.ObjectType):
     result = schema.execute(query)
     assert not result.errors
     assert result.data == expected
+
+
+def test_should_enforce_first_or_last():
+    graphene_settings.RELAY_CONNECTION_ENFORCE_FIRST_OR_LAST = True
+
+    class ReporterType(DjangoObjectType):
+
+        class Meta:
+            model = Reporter
+            interfaces = (Node, )
+
+    class Query(graphene.ObjectType):
+        all_reporters = DjangoConnectionField(ReporterType)
+
+    r = Reporter.objects.create(
+        first_name='John',
+        last_name='Doe',
+        email='johndoe@example.com',
+        a_choice=1
+    )
+
+    schema = graphene.Schema(query=Query)
+    query = '''
+        query NodeFilteringQuery {
+            allReporters {
+                edges {
+                    node {
+                        id
+                    }
+                }
+            }
+        }
+    '''
+
+    expected = {
+        'allReporters': None
+    }
+
+    result = schema.execute(query)
+    assert len(result.errors) == 1
+    assert str(result.errors[0]) == (
+        'You must provide a `first` or `last` value to properly '
+        'paginate the `allReporters` connection.'
+    )
+    assert result.data == expected
+
+
+def test_should_error_if_first_is_greater_than_max():
+    graphene_settings.RELAY_CONNECTION_MAX_LIMIT = 100
+
+    class ReporterType(DjangoObjectType):
+
+        class Meta:
+            model = Reporter
+            interfaces = (Node, )
+
+    class Query(graphene.ObjectType):
+        all_reporters = DjangoConnectionField(ReporterType)
+
+    r = Reporter.objects.create(
+        first_name='John',
+        last_name='Doe',
+        email='johndoe@example.com',
+        a_choice=1
+    )
+
+    schema = graphene.Schema(query=Query)
+    query = '''
+        query NodeFilteringQuery {
+            allReporters(first: 101) {
+                edges {
+                    node {
+                        id
+                    }
+                }
+            }
+        }
+    '''
+
+    expected = {
+        'allReporters': None
+    }
+
+    result = schema.execute(query)
+    assert len(result.errors) == 1
+    assert str(result.errors[0]) == (
+        'Requesting 101 records on the `allReporters` connection '
+        'exceeds the `first` limit of 100 records.'
+    )
+    assert result.data == expected
+
+    graphene_settings.RELAY_CONNECTION_ENFORCE_FIRST_OR_LAST = False