added ability to opt out from forward/backwards cursor pagination (#2528)

Co-authored-by: Pascal Senn <senn.pasc@gmail.com>

Author: icanhasjonas

src/HotChocolate/Core/src/Types.CursorPagination/Extensions/PagingObjectFieldDescriptorExtensions.cs

@@ -7,6 +7,7 @@
 using HotChocolate.Types.Descriptors;
 using HotChocolate.Types.Pagination;
 using static HotChocolate.Utilities.ThrowHelper;
+using static HotChocolate.Types.Pagination.PagingDefaults;
 
 namespace HotChocolate.Types
 {
@@ -41,15 +42,29 @@ public static IObjectFieldDescriptor UsePaging(
 
             resolvePagingProvider ??= ResolvePagingProvider;
 
-            descriptor.AddPagingArguments();
-
             PagingHelper.UsePaging(
                 descriptor,
                 type,
                 entityType,
                 (services, source) => resolvePagingProvider(services, source),
                 options);
 
+            descriptor
+                .Extend()
+                .OnBeforeCreate((c, d) =>
+                {
+                    if (!(c.ContextData.TryGetValue(typeof(PagingOptions).FullName!, out var obj) &&
+                       obj is PagingOptions pagingOptions))
+                    {
+                        pagingOptions = default;
+                    }
+
+                    var descriptor = ObjectFieldDescriptor.From(c, d);
+                    descriptor.AddPagingArguments(
+                        pagingOptions.AllowBackwardPagination ?? AllowBackwardPagination);
+                    descriptor.CreateDefinition();
+                });
+
             descriptor
                 .Extend()
                 .OnBeforeCreate(
@@ -76,7 +91,22 @@ public static IInterfaceFieldDescriptor UsePaging(
             }
 
             descriptor
-                .AddPagingArguments()
+                .Extend()
+                .OnBeforeCreate((c, d) =>
+                {
+                    if (!(c.ContextData.TryGetValue(typeof(PagingOptions).FullName!, out var obj) &&
+                       obj is PagingOptions pagingOptions))
+                    {
+                        pagingOptions = default;
+                    }
+
+                    var descriptor = InterfaceFieldDescriptor.From(c, d);
+                    descriptor.AddPagingArguments(
+                        pagingOptions.AllowBackwardPagination ?? AllowBackwardPagination);
+                    descriptor.CreateDefinition();
+                });
+
+            descriptor
                 .Extend()
                 .OnBeforeCreate(
                     (c, d) => d.Type = CreateConnectionTypeRef(c, d.Member, type, options));
@@ -85,33 +115,49 @@ public static IInterfaceFieldDescriptor UsePaging(
         }
 
         public static IObjectFieldDescriptor AddPagingArguments(
-            this IObjectFieldDescriptor descriptor)
+            this IObjectFieldDescriptor descriptor,
+            bool allowBackwardPagination = true)
         {
             if (descriptor == null)
             {
                 throw new ArgumentNullException(nameof(descriptor));
             }
 
-            return descriptor
+            descriptor
                 .Argument(CursorPagingArgumentNames.First, a => a.Type<IntType>())
-                .Argument(CursorPagingArgumentNames.After, a => a.Type<StringType>())
-                .Argument(CursorPagingArgumentNames.Last, a => a.Type<IntType>())
-                .Argument(CursorPagingArgumentNames.Before, a => a.Type<StringType>());
+                .Argument(CursorPagingArgumentNames.After, a => a.Type<StringType>());
+
+            if (allowBackwardPagination)
+            {
+                descriptor
+                    .Argument(CursorPagingArgumentNames.Last, a => a.Type<IntType>())
+                    .Argument(CursorPagingArgumentNames.Before, a => a.Type<StringType>());
+            }
+
+            return descriptor;
         }
 
         public static IInterfaceFieldDescriptor AddPagingArguments(
-            this IInterfaceFieldDescriptor descriptor)
+            this IInterfaceFieldDescriptor descriptor,
+            bool allowBackwardPagination = true)
         {
             if (descriptor == null)
             {
                 throw new ArgumentNullException(nameof(descriptor));
             }
 
-            return descriptor
+            descriptor
                 .Argument(CursorPagingArgumentNames.First, a => a.Type<IntType>())
-                .Argument(CursorPagingArgumentNames.After, a => a.Type<StringType>())
-                .Argument(CursorPagingArgumentNames.Last, a => a.Type<IntType>())
-                .Argument(CursorPagingArgumentNames.Before, a => a.Type<StringType>());
+                .Argument(CursorPagingArgumentNames.After, a => a.Type<StringType>());
+
+            if (allowBackwardPagination)
+            {
+                descriptor
+                    .Argument(CursorPagingArgumentNames.Last, a => a.Type<IntType>())
+                    .Argument(CursorPagingArgumentNames.Before, a => a.Type<StringType>());
+            }
+
+            return descriptor;
         }
 
         private static ITypeReference CreateConnectionTypeRef(

src/HotChocolate/Core/src/Types.CursorPagination/Extensions/UsePagingAttribute.cs

@@ -13,6 +13,7 @@ public sealed class UsePagingAttribute : DescriptorAttribute
         private int? _defaultPageSize;
         private int? _maxPageSize;
         private bool? _includeTotalCount;
+        private bool? _allowBackwardPagination;
 
         /// <summary>
         /// Applies the offset paging middleware to the annotated property.
@@ -28,11 +29,13 @@ public UsePagingAttribute(Type? type = null)
         /// <summary>
         /// The schema type representation of the item type.
         /// </summary>
-        
-        public Type? SchemaType 
-        { 
-            [Obsolete("Use Type.")] get => Type; 
-            [Obsolete("Use the new constructor.")] set => Type = value; 
+
+        public Type? SchemaType
+        {
+            [Obsolete("Use Type.")]
+            get => Type;
+            [Obsolete("Use the new constructor.")]
+            set => Type = value;
         }
 
         /// <summary>
@@ -67,6 +70,15 @@ public bool IncludeTotalCount
             set => _includeTotalCount = value;
         }
 
+        /// <summary>
+        /// Allow backward paging using <c>last</c> and <c>before</c>
+        /// </summary>
+        public bool AllowBackwardPagination
+        {
+            get => _allowBackwardPagination ?? PagingDefaults.AllowBackwardPagination;
+            set => _allowBackwardPagination = value;
+        }
+
         protected override void TryConfigure(
             IDescriptorContext context,
             IDescriptor descriptor,
@@ -82,7 +94,8 @@ protected override void TryConfigure(
                         {
                             DefaultPageSize = _defaultPageSize,
                             MaxPageSize = _maxPageSize,
-                            IncludeTotalCount = _includeTotalCount
+                            IncludeTotalCount = _includeTotalCount,
+                            AllowBackwardPagination = AllowBackwardPagination
                         });
                 }
                 else if (descriptor is IInterfaceFieldDescriptor ifd)
@@ -93,7 +106,8 @@ protected override void TryConfigure(
                         {
                             DefaultPageSize = _defaultPageSize,
                             MaxPageSize = _maxPageSize,
-                            IncludeTotalCount = _includeTotalCount
+                            IncludeTotalCount = _includeTotalCount,
+                            AllowBackwardPagination = AllowBackwardPagination
                         });
                 }
             }

src/HotChocolate/Core/src/Types/Types/Pagination/PagingDefaults.cs

@@ -7,5 +7,7 @@ public static class PagingDefaults
         public const int MaxPageSize = 50;
 
         public const bool IncludeTotalCount = false;
+
+        public const bool AllowBackwardPagination = true;
     }
 }

src/HotChocolate/Core/src/Types/Types/Pagination/PagingOptions.cs

@@ -20,5 +20,10 @@ public struct PagingOptions
         /// shall be included into the paging result type.
         /// </summary>
         public bool? IncludeTotalCount { get; set; }
+
+        /// <summary>
+        /// Defines if backward pagination is allowed or deactivated
+        /// </summary>
+        public bool? AllowBackwardPagination { get; set; }
     }
 }

src/HotChocolate/Core/test/Types.CursorPagination.Tests/IntegrationTests.cs

@@ -611,6 +611,39 @@ public async Task Attribute_Interface_With_Paging_Field()
             schema.Print().MatchSnapshot();
         }
 
+        [Fact]
+        public async Task Deactivate_BackwardPagination()
+        {
+            IRequestExecutor executor =
+                await new ServiceCollection()
+                    .AddGraphQL()
+                    .AddQueryType<QueryType>()
+                    .SetPagingOptions(new PagingOptions { AllowBackwardPagination = false })
+                    .Services
+                    .BuildServiceProvider()
+                    .GetRequestExecutorAsync();
+
+            executor.Schema.Print().MatchSnapshot();
+        }
+
+        [Fact]
+        public async Task Deactivate_BackwardPagination_Interface()
+        {
+            Snapshot.FullName();
+
+            ISchema schema =
+                await new ServiceCollection()
+                    .AddGraphQL()
+                    .AddQueryType<QueryAttr>()
+                    .SetPagingOptions(new PagingOptions { AllowBackwardPagination = false })
+                    .AddInterfaceType<ISome>(d => d.Field(t => t.ExplicitType()).UsePaging())
+                    .Services
+                    .BuildServiceProvider()
+                    .GetSchemaAsync();
+
+            schema.Print().MatchSnapshot();
+        }
+
         public class QueryType : ObjectType<Query>
         {
             protected override void Configure(IObjectTypeDescriptor<Query> descriptor)
@@ -755,7 +788,7 @@ public MockExecutable(IQueryable<T> source)
             _source = source;
         }
 
-        public object Source =>_source;
+        public object Source => _source;
 
         public ValueTask<IList> ToListAsync(CancellationToken cancellationToken)
         {

src/HotChocolate/Core/test/Types.CursorPagination.Tests/__snapshots__/IntegrationTests.Deactivate_BackwardPagination.snap

@@ -0,0 +1,68 @@
+schema {
+  query: Query
+}
+
+type Foo {
+  bar: String!
+}
+
+"A connection to a list of items."
+type FooConnection {
+  "Information to aid in pagination."
+  pageInfo: PageInfo!
+  "A list of edges."
+  edges: [FooEdge!]
+  "A flattened list of the nodes."
+  nodes: [[Foo!]!]
+  totalCount: Int!
+}
+
+"An edge in a connection."
+type FooEdge {
+  "A cursor for use in pagination."
+  cursor: String!
+  "The item at the end of the edge."
+  node: [Foo!]!
+}
+
+"Information about pagination in a connection."
+type PageInfo {
+  "Indicates whether more edges exist following the set defined by the clients arguments."
+  hasNextPage: Boolean!
+  "Indicates whether more edges exist prior the set defined by the clients arguments."
+  hasPreviousPage: Boolean!
+  "When paginating backwards, the cursor to continue."
+  startCursor: String
+  "When paginating forwards, the cursor to continue."
+  endCursor: String
+}
+
+type Query {
+  letters(first: Int after: String): StringConnection
+  explicitType(first: Int after: String): StringConnection
+  nestedObjectList(first: Int after: String): FooConnection
+}
+
+"A connection to a list of items."
+type StringConnection {
+  "Information to aid in pagination."
+  pageInfo: PageInfo!
+  "A list of edges."
+  edges: [StringEdge!]
+  "A flattened list of the nodes."
+  nodes: [String!]
+}
+
+"An edge in a connection."
+type StringEdge {
+  "A cursor for use in pagination."
+  cursor: String!
+  "The item at the end of the edge."
+  node: String!
+}
+
+"The `@defer` directive may be provided for fragment spreads and inline fragments to inform the executor to delay the execution of the current fragment to indicate deprioritization of the current fragment. A query with `@defer` directive will cause the request to potentially return multiple responses, where non-deferred data is delivered in the initial response and data deferred is delivered in a subsequent response. `@include` and `@skip` take precedence over `@defer`."
+directive @defer("If this argument label has a value other than null, it will be passed on to the result of this defer directive. This label is intended to give client applications a way to identify to which fragment a deferred result belongs to." label: String "Deferred when true." if: Boolean) on FRAGMENT_SPREAD | INLINE_FRAGMENT
+
+"The `@stream` directive may be provided for a field of `List` type so that the backend can leverage technology such as asynchronous iterators to provide a partial list in the initial response, and additional list items in subsequent responses. `@include` and `@skip` take precedence over `@stream`."
+directive @stream("If this argument label has a value other than null, it will be passed on to the result of this stream directive. This label is intended to give client applications a way to identify to which fragment a streamed result belongs to." label: String "The initial elements that shall be send down to the consumer." initialCount: Int! "Streamed when true." if: Boolean!) on FIELD

src/HotChocolate/Core/test/Types.CursorPagination.Tests/__snapshots__/IntegrationTests.Deactivate_BackwardPagination_Interface.snap

@@ -0,0 +1,72 @@
+schema {
+  query: QueryAttr
+}
+
+interface ISome {
+  explicitType(first: Int after: String): StringConnection
+}
+
+type Foo {
+  bar: String!
+}
+
+"A connection to a list of items."
+type FooConnection {
+  "Information to aid in pagination."
+  pageInfo: PageInfo!
+  "A list of edges."
+  edges: [FooEdge!]
+  "A flattened list of the nodes."
+  nodes: [[Foo!]!]
+  totalCount: Int!
+}
+
+"An edge in a connection."
+type FooEdge {
+  "A cursor for use in pagination."
+  cursor: String!
+  "The item at the end of the edge."
+  node: [Foo!]!
+}
+
+"Information about pagination in a connection."
+type PageInfo {
+  "Indicates whether more edges exist following the set defined by the clients arguments."
+  hasNextPage: Boolean!
+  "Indicates whether more edges exist prior the set defined by the clients arguments."
+  hasPreviousPage: Boolean!
+  "When paginating backwards, the cursor to continue."
+  startCursor: String
+  "When paginating forwards, the cursor to continue."
+  endCursor: String
+}
+
+type QueryAttr {
+  nestedObjectList(first: Int after: String): FooConnection
+  letters(first: Int after: String): StringConnection
+  explicitType(first: Int after: String): StringConnection
+}
+
+"A connection to a list of items."
+type StringConnection {
+  "Information to aid in pagination."
+  pageInfo: PageInfo!
+  "A list of edges."
+  edges: [StringEdge!]
+  "A flattened list of the nodes."
+  nodes: [String!]
+}
+
+"An edge in a connection."
+type StringEdge {
+  "A cursor for use in pagination."
+  cursor: String!
+  "The item at the end of the edge."
+  node: String!
+}
+
+"The `@defer` directive may be provided for fragment spreads and inline fragments to inform the executor to delay the execution of the current fragment to indicate deprioritization of the current fragment. A query with `@defer` directive will cause the request to potentially return multiple responses, where non-deferred data is delivered in the initial response and data deferred is delivered in a subsequent response. `@include` and `@skip` take precedence over `@defer`."
+directive @defer("If this argument label has a value other than null, it will be passed on to the result of this defer directive. This label is intended to give client applications a way to identify to which fragment a deferred result belongs to." label: String "Deferred when true." if: Boolean) on FRAGMENT_SPREAD | INLINE_FRAGMENT
+
+"The `@stream` directive may be provided for a field of `List` type so that the backend can leverage technology such as asynchronous iterators to provide a partial list in the initial response, and additional list items in subsequent responses. `@include` and `@skip` take precedence over `@stream`."
+directive @stream("If this argument label has a value other than null, it will be passed on to the result of this stream directive. This label is intended to give client applications a way to identify to which fragment a streamed result belongs to." label: String "The initial elements that shall be send down to the consumer." initialCount: Int! "Streamed when true." if: Boolean!) on FIELD