change Type to ResourceType and add EntityType that defaults to ResourceType. updated DefaultEntityRepository to correctly attach relationship when creating a resource

Author: roblankey

src/Examples/JsonApiDotNetCoreExample/Models/Resources/CourseResource.cs

@@ -1,6 +1,7 @@
 using JsonApiDotNetCore.Models;
 using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
+using JsonApiDotNetCoreExample.Models.Entities;
 
 namespace JsonApiDotNetCoreExample.Models.Resources
 {
@@ -17,7 +18,7 @@ public class CourseResource : Identifiable
         [Attr("description")]
         public string Description { get; set; }
 
-        [HasOne("department")]
+        [HasOne("department", withEntityType: typeof(DepartmentEntity))]
         public DepartmentResource Department { get; set; }
         public int? DepartmentId { get; set; }
 

src/JsonApiDotNetCore/Builders/ContextGraphBuilder.cs

@@ -165,10 +165,10 @@ protected virtual List<RelationshipAttribute> GetRelationships(Type entityType)
 
                 attribute.PublicRelationshipName = attribute.PublicRelationshipName ?? JsonApiOptions.ResourceNameFormatter.FormatPropertyName(prop);
                 attribute.InternalRelationshipName = prop.Name;
-                attribute.Type = GetRelationshipType(attribute, prop);
+                attribute.ResourceType = GetRelationshipType(attribute, prop);
                 attributes.Add(attribute);
 
-                if(attribute is HasManyThroughAttribute hasManyThroughAttribute) {
+                if (attribute is HasManyThroughAttribute hasManyThroughAttribute) {
                     var throughProperty = properties.SingleOrDefault(p => p.Name == hasManyThroughAttribute.InternalThroughName);
                     if(throughProperty == null)
                         throw new JsonApiSetupException($"Invalid '{nameof(HasManyThroughAttribute)}' on type '{entityType}'. Type does not contain a property named '{hasManyThroughAttribute.InternalThroughName}'.");
@@ -198,26 +198,21 @@ protected virtual List<RelationshipAttribute> GetRelationships(Type entityType)
                         ?? throw new JsonApiSetupException($"{hasManyThroughAttribute.ThroughType} does not contain a relationship id property to type {entityType} with name {leftIdPropertyName}");
 
                     // Article → ArticleTag.Tag
-                    hasManyThroughAttribute.RightProperty = throughProperties.SingleOrDefault(x => x.PropertyType == hasManyThroughAttribute.Type)
-                        ?? throw new JsonApiSetupException($"{hasManyThroughAttribute.ThroughType} does not contain a navigation property to type {hasManyThroughAttribute.Type}");
+                    hasManyThroughAttribute.RightProperty = throughProperties.SingleOrDefault(x => x.PropertyType == hasManyThroughAttribute.ResourceType)
+                        ?? throw new JsonApiSetupException($"{hasManyThroughAttribute.ThroughType} does not contain a navigation property to type {hasManyThroughAttribute.ResourceType}");
 
                     // ArticleTag.TagId
                     var rightIdPropertyName = JsonApiOptions.RelatedIdMapper.GetRelatedIdPropertyName(hasManyThroughAttribute.RightProperty.Name);
                     hasManyThroughAttribute.RightIdProperty = throughProperties.SingleOrDefault(x => x.Name == rightIdPropertyName)
-                        ?? throw new JsonApiSetupException($"{hasManyThroughAttribute.ThroughType} does not contain a relationship id property to type {hasManyThroughAttribute.Type} with name {rightIdPropertyName}");
+                        ?? throw new JsonApiSetupException($"{hasManyThroughAttribute.ThroughType} does not contain a relationship id property to type {hasManyThroughAttribute.ResourceType} with name {rightIdPropertyName}");
                 }
             }
 
             return attributes;
         }
 
-        protected virtual Type GetRelationshipType(RelationshipAttribute relation, PropertyInfo prop)
-        {
-            if (relation.IsHasMany)
-                return prop.PropertyType.GetGenericArguments()[0];
-            else
-                return prop.PropertyType;
-        }
+        protected virtual Type GetRelationshipType(RelationshipAttribute relation, PropertyInfo prop) =>
+            relation.IsHasMany ? prop.PropertyType.GetGenericArguments()[0] : prop.PropertyType;
 
         private Type GetResourceDefinitionType(Type entityType) => typeof(ResourceDefinition<>).MakeGenericType(entityType);
 

src/JsonApiDotNetCore/Builders/DocumentBuilder.cs

@@ -242,7 +242,7 @@ private List<ResourceObject> IncludeSingleResourceRelationships(
         {
             if (relationshipChainIndex < relationshipChain.Length)
             {
-                var nextContextEntity = _jsonApiContext.ResourceGraph.GetContextEntity(relationship.Type);
+                var nextContextEntity = _jsonApiContext.ResourceGraph.GetContextEntity(relationship.ResourceType);
                 var resource = (IIdentifiable)navigationEntity;
                 // recursive call
                 if (relationshipChainIndex < relationshipChain.Length - 1)
@@ -329,7 +329,7 @@ private ResourceIdentifierObject GetIndependentRelationshipIdentifier(HasOneAttr
             if (independentRelationshipIdentifier == null)
                 return null;
 
-            var relatedContextEntity = _jsonApiContext.ResourceGraph.GetContextEntity(hasOne.Type);
+            var relatedContextEntity = _jsonApiContext.ResourceGraph.GetContextEntity(hasOne.ResourceType);
             if (relatedContextEntity == null) // TODO: this should probably be a debug log at minimum
                 return null;
 

src/JsonApiDotNetCore/Data/DefaultEntityRepository.cs

@@ -155,15 +155,15 @@ public virtual async Task<TEntity> CreateAsync(TEntity entity)
         protected virtual void AttachRelationships(TEntity entity = null)
         {
             AttachHasManyPointers(entity);
-            AttachHasOnePointers();
+            AttachHasOnePointers(entity);
         }
 
         /// <inheritdoc />
         public void DetachRelationshipPointers(TEntity entity)
         {
             foreach (var hasOneRelationship in _jsonApiContext.HasOneRelationshipPointers.Get())
             {
-                _context.Entry(hasOneRelationship.Value).State = EntityState.Detached;
+                _context.Entry(hasOneRelationship.Key.EntityType).State = EntityState.Detached;
             }
 
             foreach (var hasManyRelationship in _jsonApiContext.HasManyRelationshipPointers.Get())
@@ -227,12 +227,18 @@ private void AttachHasManyThrough(TEntity entity, HasManyThroughAttribute hasMan
         /// This is used to allow creation of HasOne relationships when the
         /// independent side of the relationship already exists.
         /// </summary>
-        private void AttachHasOnePointers()
+        private void AttachHasOnePointers(TEntity entity)
         {
             var relationships = _jsonApiContext.HasOneRelationshipPointers.Get();
             foreach (var relationship in relationships)
-                if (_context.Entry(relationship.Value).State == EntityState.Detached && _context.EntityIsTracked(relationship.Value) == false)
-                    _context.Entry(relationship.Value).State = EntityState.Unchanged;
+            {
+                var relatedEntityType = relationship.Key.EntityType; // DepartmentEntity
+                var relatedEntityMember = typeof(TEntity).GetProperties().SingleOrDefault(p => p.PropertyType == relatedEntityType)?.Name;
+                var relatedEntity = relatedEntityMember == null ? null : entity.GetType().GetProperty(relatedEntityMember)?.GetValue(entity);
+                
+                if (relatedEntity != null && _context.Entry(relatedEntity).State == EntityState.Detached && _context.EntityIsTracked((IIdentifiable)relatedEntity) == false)
+                    _context.Entry(relatedEntity).State = EntityState.Unchanged;
+            }
         }
 
         /// <inheritdoc />
@@ -265,7 +271,7 @@ public async Task UpdateRelationshipsAsync(object parent, RelationshipAttribute
             // of the property...
             var typeToUpdate = (relationship is HasManyThroughAttribute hasManyThrough)
                 ? hasManyThrough.ThroughType
-                : relationship.Type;
+                : relationship.ResourceType;
 
             var genericProcessor = _genericProcessorFactory.GetProcessor<IGenericProcessor>(typeof(GenericProcessor<>), typeToUpdate);
             await genericProcessor.UpdateRelationshipsAsync(parent, relationship, relationshipIds);
@@ -317,7 +323,7 @@ public virtual IQueryable<TEntity> Include(IQueryable<TEntity> entities, string
                     : $"{internalRelationshipPath}.{relationship.RelationshipPath}";
 
                 if(i < relationshipChain.Length)
-                    entity = _jsonApiContext.ResourceGraph.GetContextEntity(relationship.Type);
+                    entity = _jsonApiContext.ResourceGraph.GetContextEntity(relationship.ResourceType);
             }
 
             return entities.Include(internalRelationshipPath);

src/JsonApiDotNetCore/Extensions/IQueryableExtensions.cs

@@ -254,7 +254,7 @@ private static IQueryable<TSource> CallGenericWhereMethod<TSource>(IQueryable<TS
                 if (relationProperty == null)
                     throw new ArgumentException($"'{filter.Relationship.InternalRelationshipName}' is not a valid relationship of '{concreteType}'");
 
-                var relatedType = filter.Relationship.Type;
+                var relatedType = filter.Relationship.ResourceType;
                 property = relatedType.GetProperty(filter.Attribute.InternalAttributeName);
                 if (property == null)
                     throw new ArgumentException($"'{filter.Attribute.InternalAttributeName}' is not a valid attribute of '{filter.Relationship.InternalRelationshipName}'");

src/JsonApiDotNetCore/Models/HasManyAttribute.cs

@@ -11,6 +11,7 @@ public class HasManyAttribute : RelationshipAttribute
         /// <param name="publicName">The relationship name as exposed by the API</param>
         /// <param name="documentLinks">Which links are available. Defaults to <see cref="Link.All"/></param>
         /// <param name="canInclude">Whether or not this relationship can be included using the <c>?include=public-name</c> query string</param>
+        /// <param name="withEntityType">If the entity model of this relationship refers to a different type, specify that here</param>
         /// 
         /// <example>
         /// 
@@ -23,8 +24,8 @@ public class HasManyAttribute : RelationshipAttribute
         /// </code>
         /// 
         /// </example>
-        public HasManyAttribute(string publicName = null, Link documentLinks = Link.All, bool canInclude = true)
-        : base(publicName, documentLinks, canInclude)
+        public HasManyAttribute(string publicName = null, Link documentLinks = Link.All, bool canInclude = true, Type withEntityType = null)
+        : base(publicName, documentLinks, canInclude, withEntityType)
         { }
 
         /// <summary>

src/JsonApiDotNetCore/Models/HasOneAttribute.cs

@@ -11,6 +11,7 @@ public class HasOneAttribute : RelationshipAttribute
         /// 
         /// <param name="publicName">The relationship name as exposed by the API</param>
         /// <param name="documentLinks">Which links are available. Defaults to <see cref="Link.All"/></param>
+        /// <param name="withEntityType">If the entity model of this relationship refers to a different type, specify that here</param>
         /// <param name="canInclude">Whether or not this relationship can be included using the <c>?include=public-name</c> query string</param>
         /// <param name="withForeignKey">The foreign key property name. Defaults to <c>"{RelationshipName}Id"</c></param>
         /// 
@@ -20,21 +21,21 @@ public class HasOneAttribute : RelationshipAttribute
         /// <code>
         /// public class Article : Identifiable 
         /// {
-        ///     [HasOne("author", withForiegnKey: nameof(AuthorKey)]
+        ///     [HasOne("author", withForeignKey: nameof(AuthorKey)]
         ///     public Author Author { get; set; }
         ///     public int AuthorKey { get; set; }
         /// }
         /// </code>
         /// 
         /// </example>
-        public HasOneAttribute(string publicName = null, Link documentLinks = Link.All, bool canInclude = true, string withForeignKey = null)
-        : base(publicName, documentLinks, canInclude)
+        public HasOneAttribute(string publicName = null, Link documentLinks = Link.All, Type withEntityType = null, bool canInclude = true, string withForeignKey = null)
+        : base(publicName, documentLinks, canInclude, withEntityType)
         {
             _explicitIdentifiablePropertyName = withForeignKey;
         }
 
         private readonly string _explicitIdentifiablePropertyName;
-
+        
         /// <summary>
         /// The independent resource identifier.
         /// </summary>
@@ -49,7 +50,7 @@ public HasOneAttribute(string publicName = null, Link documentLinks = Link.All,
         /// <param name="newValue">The new property value</param>
         public override void SetValue(object resource, object newValue)
         {
-            var propertyName = (newValue?.GetType() == Type)
+            var propertyName = (newValue?.GetType() == ResourceType)
                 ? InternalRelationshipName
                 : IdentifiablePropertyName;
 

src/JsonApiDotNetCore/Models/RelationshipAttribute.cs

@@ -6,11 +6,12 @@ namespace JsonApiDotNetCore.Models
 {
     public abstract class RelationshipAttribute : Attribute
     {
-        protected RelationshipAttribute(string publicName, Link documentLinks, bool canInclude)
+        protected RelationshipAttribute(string publicName, Link documentLinks, bool canInclude, Type withEntityType)
         {
             PublicRelationshipName = publicName;
             DocumentLinks = documentLinks;
             CanInclude = canInclude;
+            _entityType = withEntityType;
         }
 
         public string PublicRelationshipName { get; internal set; }
@@ -26,7 +27,11 @@ protected RelationshipAttribute(string publicName, Link documentLinks, bool canI
         /// public List<Tag> Tags { get; set; } // Type => Tag
         /// </code>
         /// </example>
-        public Type Type { get; internal set; }
+        public Type ResourceType { get; internal set; }
+
+        private readonly Type _entityType;
+        public Type EntityType => _entityType == null ? ResourceType : _entityType;
+
         public bool IsHasMany => GetType() == typeof(HasManyAttribute) || GetType().Inherits(typeof(HasManyAttribute));
         public bool IsHasOne => GetType() == typeof(HasOneAttribute);
         public Link DocumentLinks { get; } = Link.All;
@@ -55,10 +60,10 @@ public bool TryGetHasMany(out HasManyAttribute result)
         }
 
         public abstract void SetValue(object entity, object newValue);
-
+        
         public object GetValue(object entity) => entity
-            ?.GetType()
-            .GetProperty(InternalRelationshipName)
+            ?.GetType()?
+            .GetProperty(InternalRelationshipName)?
             .GetValue(entity);
 
         public override string ToString()

src/JsonApiDotNetCore/Serialization/JsonApiDeSerializer.cs

@@ -218,7 +218,7 @@ private object SetHasOneRelationship(object entity,
             if(included != null) 
             {
                 var navigationPropertyValue = attr.GetValue(entity);
-                var resourceGraphEntity = _jsonApiContext.ResourceGraph.GetContextEntity(attr.Type);
+                var resourceGraphEntity = _jsonApiContext.ResourceGraph.GetContextEntity(attr.ResourceType);
                 if(navigationPropertyValue != null && resourceGraphEntity != null)
                 {
                     var includedResource = included.SingleOrDefault(r => r.Type == rio.Type && r.Id == rio.Id);
@@ -292,7 +292,7 @@ private object SetHasManyRelationship(object entity,
                     return instance;
                 });
 
-                var convertedCollection = TypeHelper.ConvertCollection(relatedResources, attr.Type);
+                var convertedCollection = TypeHelper.ConvertCollection(relatedResources, attr.ResourceType);
 
                 attr.SetValue(entity, convertedCollection);
 
@@ -305,7 +305,7 @@ private object SetHasManyRelationship(object entity,
         private IIdentifiable GetIncludedRelationship(ResourceIdentifierObject relatedResourceIdentifier, List<ResourceObject> includedResources, RelationshipAttribute relationshipAttr)
         {
             // at this point we can be sure the relationshipAttr.Type is IIdentifiable because we were able to successfully build the ResourceGraph
-            var relatedInstance = relationshipAttr.Type.New<IIdentifiable>();
+            var relatedInstance = relationshipAttr.ResourceType.New<IIdentifiable>();
             relatedInstance.StringId = relatedResourceIdentifier.Id;
 
             // can't provide any more data other than the rio since it is not contained in the included section
@@ -316,9 +316,9 @@ private IIdentifiable GetIncludedRelationship(ResourceIdentifierObject relatedRe
             if (includedResource == null)
                 return relatedInstance;
 
-            var contextEntity = _jsonApiContext.ResourceGraph.GetContextEntity(relationshipAttr.Type);
+            var contextEntity = _jsonApiContext.ResourceGraph.GetContextEntity(relationshipAttr.ResourceType);
             if (contextEntity == null)
-                throw new JsonApiException(400, $"Included type '{relationshipAttr.Type}' is not a registered json:api resource.");
+                throw new JsonApiException(400, $"Included type '{relationshipAttr.ResourceType}' is not a registered json:api resource.");
 
             SetEntityAttributes(relatedInstance, contextEntity, includedResource.Attributes);
 

src/JsonApiDotNetCore/Services/EntityResourceService.cs

@@ -170,7 +170,7 @@ public virtual async Task UpdateRelationshipsAsync(TId id, string relationshipNa
                 .Relationships
                 .FirstOrDefault(r => r.Is(relationshipName));
 
-            var relationshipType = relationship.Type;
+            var relationshipType = relationship.ResourceType;
 
             // update relationship type with internalname
             var entityProperty = typeof(TEntity).GetProperty(relationship.InternalRelationshipName);
@@ -180,15 +180,15 @@ public virtual async Task UpdateRelationshipsAsync(TId id, string relationshipNa
                     $"could not be found on entity.");
             }
 
-            relationship.Type = relationship.IsHasMany
+            relationship.ResourceType = relationship.IsHasMany
                 ? entityProperty.PropertyType.GetGenericArguments()[0]
                 : entityProperty.PropertyType;
 
             var relationshipIds = relationships.Select(r => r?.Id?.ToString());
 
             await _entities.UpdateRelationshipsAsync(entity, relationship, relationshipIds);
 
-            relationship.Type = relationshipType;
+            relationship.ResourceType = relationshipType;
         }
 
         protected virtual async Task<IEnumerable<TResource>> ApplyPageQueryAsync(IQueryable<TEntity> entities)

src/JsonApiDotNetCore/Services/Operations/Processors/GetOpProcessor.cs

@@ -135,7 +135,7 @@ private async Task<object> GetRelationshipAsync(Operation operation)
             // TODO: need a better way to get the ContextEntity from a relationship name
             // when no generic parameter is available
             var relationshipType = _resourceGraph.GetContextEntity(operation.GetResourceTypeName())
-                .Relationships.Single(r => r.Is(operation.Ref.Relationship)).Type;
+                .Relationships.Single(r => r.Is(operation.Ref.Relationship)).ResourceType;
 
             var relatedContextEntity = _jsonApiContext.ResourceGraph.GetContextEntity(relationshipType);