Feat/#451

src/JsonApiDotNetCore/Builders/DocumentBuilder.cs

@@ -168,7 +168,7 @@ private RelationshipData GetRelationshipData(RelationshipAttribute attr, Context
 
             var relationshipData = new RelationshipData();
 
-            if (attr.DocumentLinks.HasFlag(Link.None) == false)
+            if (_jsonApiContext.Options.DefaultRelationshipLinks.HasFlag(Link.None) == false && attr.DocumentLinks.HasFlag(Link.None) == false)
             {
                 relationshipData.Links = new Links();
                 if (attr.DocumentLinks.HasFlag(Link.Self))

src/JsonApiDotNetCore/Configuration/JsonApiOptions.cs

@@ -102,6 +102,26 @@ public class JsonApiOptions
         /// </example>
         public bool RelativeLinks { get; set; }
 
+        /// <summary>
+        /// Which links to include in relationships. Defaults to <see cref="Link.All"/>.
+        /// </summary>
+        /// <example>
+        /// <code>
+        /// options.DefaultRelationshipLinks = Link.None;
+        /// </code>
+        /// <code>
+        /// {
+        ///   "type": "articles",
+        ///   "id": "4309",
+        ///   "relationships": {
+        ///      "author": {}
+        ///      }
+        ///   }
+        /// }
+        /// </code>
+        /// </example>
+        public Link DefaultRelationshipLinks { get; set; } = Link.All;
+
         /// <summary>
         /// Whether or not to allow all custom query parameters.
         /// </summary>

test/UnitTests/Builders/DocumentBuilder_Tests.cs

@@ -122,6 +122,30 @@ public void Related_Links_Can_Be_Disabled()
             Assert.Null(document.Data.Relationships["related-model"].Links);
         }
 
+        [Fact]
+        public void Related_Links_Can_Be_Disabled_Globally()
+        {
+            // arrange
+            _pageManager.PageSize = 1;
+            _pageManager.TotalRecords = 1;
+            _pageManager.CurrentPage = 1;
+
+            _options.DefaultRelationshipLinks = Link.None;
+
+            _jsonApiContextMock
+                .Setup(m => m.ResourceGraph)
+                .Returns(_options.ResourceGraph);
+
+            var documentBuilder = new DocumentBuilder(_jsonApiContextMock.Object);
+            var entity = new RelatedModel();
+
+            // act
+            var document = documentBuilder.Build(entity);
+
+            // assert
+            Assert.Null(document.Data.Relationships["models"].Links);
+        }
+
         [Fact]
         public void Related_Data_Included_In_Relationships_By_Default()
         {