Feature/#162

src/Examples/JsonApiDotNetCoreExample/Models/Person.cs

@@ -20,6 +20,9 @@ public class Person : Identifiable, IHasMeta
 
         [HasMany("todo-collections")]
         public virtual List<TodoItemCollection> TodoItemCollections { get; set; }
+
+        [HasOne("unincludeable-item", Link.All, false)]
+        public virtual TodoItem UnIncludeableItem { get; set; }
 
         public Dictionary<string, object> GetMeta(IJsonApiContext context)
         {

src/JsonApiDotNetCore/Data/DefaultEntityRepository.cs

@@ -131,11 +131,18 @@ public virtual IQueryable<TEntity> Include(IQueryable<TEntity> entities, string
         {
             var entity = _jsonApiContext.RequestEntity;
             var relationship = entity.Relationships.FirstOrDefault(r => r.PublicRelationshipName == relationshipName);
-            if (relationship != null)
-                return entities.Include(relationship.InternalRelationshipName);
+            if (relationship == null) 
+            {
+                throw new JsonApiException(400, $"Invalid relationship {relationshipName} on {entity.EntityName}",
+                    $"{entity.EntityName} does not have a relationship named {relationshipName}");
+            }
+
+            if (!relationship.CanInclude)
+            {
+                throw new JsonApiException(400, $"Including the relationship {relationshipName} on {entity.EntityName} is not allowed");
+            }
+            return entities.Include(relationship.InternalRelationshipName);
 
-            throw new JsonApiException(400, $"Invalid relationship {relationshipName} on {entity.EntityName}",
-                $"{entity.EntityName} does not have a relationship named {relationshipName}");
         }
 
         public virtual async Task<IEnumerable<TEntity>> PageAsync(IQueryable<TEntity> entities, int pageSize, int pageNumber)

src/JsonApiDotNetCore/Models/HasManyAttribute.cs

@@ -2,8 +2,8 @@ namespace JsonApiDotNetCore.Models
 {
     public class HasManyAttribute : RelationshipAttribute
     {
-        public HasManyAttribute(string publicName, Link documentLinks = Link.All)
-        : base(publicName, documentLinks)
+        public HasManyAttribute(string publicName, Link documentLinks = Link.All, bool canInclude = true)
+        : base(publicName, documentLinks, canInclude)
         { }
 
         public override void SetValue(object entity, object newValue)

src/JsonApiDotNetCore/Models/HasOneAttribute.cs

@@ -2,8 +2,8 @@ namespace JsonApiDotNetCore.Models
 {
     public class HasOneAttribute : RelationshipAttribute
     {
-        public HasOneAttribute(string publicName, Link documentLinks = Link.All)
-        : base(publicName, documentLinks)
+        public HasOneAttribute(string publicName, Link documentLinks = Link.All, bool canInclude = true)
+        : base(publicName, documentLinks, canInclude)
         { }
 
         public override void SetValue(object entity, object newValue)

src/JsonApiDotNetCore/Models/RelationshipAttribute.cs

@@ -4,10 +4,11 @@ namespace JsonApiDotNetCore.Models
 {
     public abstract class RelationshipAttribute : Attribute
     {
-        protected RelationshipAttribute(string publicName, Link documentLinks)
+        protected RelationshipAttribute(string publicName, Link documentLinks, bool canInclude)
         {
             PublicRelationshipName = publicName;
             DocumentLinks = documentLinks;
+            CanInclude = canInclude;
         }
 
         public string PublicRelationshipName { get; }
@@ -16,6 +17,7 @@ protected RelationshipAttribute(string publicName, Link documentLinks)
         public bool IsHasMany => GetType() == typeof(HasManyAttribute);
         public bool IsHasOne => GetType() == typeof(HasOneAttribute);
         public Link DocumentLinks { get; } = Link.All;
+        public bool CanInclude { get; }
 
         public abstract void SetValue(object entity, object newValue);
 
@@ -26,8 +28,7 @@ public override string ToString()
 
         public override bool Equals(object obj)
         {
-            var attr = obj as RelationshipAttribute;
-            if (attr == null)
+            if (!(obj is RelationshipAttribute attr))
             {
                 return false;
             }

test/JsonApiDotNetCoreExampleTests/Acceptance/Spec/DocumentTests/Included.cs

@@ -335,5 +335,29 @@ public async Task Request_ToIncludeDeeplyNestedRelationships_Returns_400()
             // assert
             Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
         }
+
+        [Fact]
+        public async Task Request_ToIncludeRelationshipMarkedCanIncludeFalse_Returns_400()
+        {
+            // arrange
+            var person = _context.People.First();
+
+            var builder = new WebHostBuilder()
+                .UseStartup<Startup>();
+
+            var httpMethod = new HttpMethod("GET");
+
+            var route = $"/api/v1/people/{person.Id}?include=unincludeable-item";
+
+            var server = new TestServer(builder);
+            var client = server.CreateClient();
+            var request = new HttpRequestMessage(httpMethod, route);
+
+            // act
+            var response = await client.SendAsync(request);
+
+            // assert
+            Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+        }
     }
 }