Native many to many (#1037)

Author: Bart Koelman

JsonApiDotNetCore.sln

@@ -18,6 +18,8 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Examples", "Examples", "{02
 EndProject
 Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "benchmarks", "benchmarks", "{076E1AE4-FD25-4684-B826-CAAE37FEA0AA}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "GettingStarted", "src\Examples\GettingStarted\GettingStarted.csproj", "{067FFD7A-C66B-473D-8471-37F5C95DF61C}"
+EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "JsonApiDotNetCoreExampleTests", "test\JsonApiDotNetCoreExampleTests\JsonApiDotNetCoreExampleTests.csproj", "{CAF331F8-9255-4D72-A1A8-A54141E99F1E}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "NoEntityFrameworkTests", "test\NoEntityFrameworkTests\NoEntityFrameworkTests.csproj", "{4F15A8F8-5BC6-45A1-BC51-03F921B726A4}"
@@ -36,8 +38,6 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "ReportsExample", "src\Examp
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "JsonApiDotNetCore", "src\JsonApiDotNetCore\JsonApiDotNetCore.csproj", "{21D27239-138D-4604-8E49-DCBE41BCE4C8}"
 EndProject
-Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "GettingStarted", "src\Examples\GettingStarted\GettingStarted.csproj", "{067FFD7A-C66B-473D-8471-37F5C95DF61C}"
-EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MultiDbContextExample", "src\Examples\MultiDbContextExample\MultiDbContextExample.csproj", "{6CAFDDBE-00AB-4784-801B-AB419C3C3A26}"
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "MultiDbContextTests", "test\MultiDbContextTests\MultiDbContextTests.csproj", "{EC3202C6-1D4C-4B14-A599-B9D3F27FE3BA}"

docs/usage/resources/relationships.md

@@ -20,7 +20,6 @@ public class TodoItem : Identifiable
 
 The left side of this relationship is of type `TodoItem` (public name: "todoItems") and the right side is of type `Person` (public name: "persons").
 
-
 ## HasMany
 
 This exposes a to-many relationship.
@@ -35,32 +34,6 @@ public class Person : Identifiable
 
 The left side of this relationship is of type `Person` (public name: "persons") and the right side is of type `TodoItem` (public name: "todoItems").
 
-
-## HasManyThrough
-
-Earlier versions of Entity Framework Core (up to v5) [did not support](https://github.com/aspnet/EntityFrameworkCore/issues/1368) many-to-many relationships without a join entity.
-For this reason, we have decided to fill this gap by allowing applications to declare a relationship as `HasManyThrough`.
-JsonApiDotNetCore will expose this relationship to the client the same way as any other `HasMany` relationship.
-However, under the covers it will use the join type and Entity Framework Core's APIs to get and set the relationship.
-
-```c#
-public class Article : Identifiable
-{
-    // tells Entity Framework Core to ignore this property
-    [NotMapped]
-
-    // tells JsonApiDotNetCore to use the join table below
-    [HasManyThrough(nameof(ArticleTags))]
-    public ICollection<Tag> Tags { get; set; }
-
-    // this is the Entity Framework Core navigation to the join table
-    public ICollection<ArticleTag> ArticleTags { get; set; }
-}
-```
-
-The left side of this relationship is of type `Article` (public name: "articles") and the right side is of type `Tag` (public name: "tags").
-
-
 ## Name
 
 There are two ways the exposed relationship name is determined:

src/Examples/JsonApiDotNetCoreExample/Data/AppDbContext.cs

@@ -18,13 +18,6 @@ public AppDbContext(DbContextOptions<AppDbContext> options)
 
         protected override void OnModelCreating(ModelBuilder builder)
         {
-            builder.Entity<TodoItemTag>()
-                .HasKey(todoItemTag => new
-                {
-                    todoItemTag.TodoItemId,
-                    todoItemTag.TagId
-                });
-
             // When deleting a person, un-assign him/her from existing todo items.
             builder.Entity<Person>()
                 .HasMany(person => person.AssignedTodoItems)

src/Examples/JsonApiDotNetCoreExample/Models/Tag.cs

@@ -1,3 +1,4 @@
+using System.Collections.Generic;
 using System.ComponentModel.DataAnnotations;
 using JetBrains.Annotations;
 using JsonApiDotNetCore.Resources;
@@ -12,5 +13,8 @@ public sealed class Tag : Identifiable
         [MinLength(1)]
         [Attr]
         public string Name { get; set; }
+
+        [HasMany]
+        public ISet<TodoItem> TodoItems { get; set; }
     }
 }

src/Examples/JsonApiDotNetCoreExample/Models/TodoItem.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.ComponentModel.DataAnnotations.Schema;
 using JetBrains.Annotations;
 using JsonApiDotNetCore.Resources;
 using JsonApiDotNetCore.Resources.Annotations;
@@ -28,10 +27,7 @@ public sealed class TodoItem : Identifiable
         [HasOne]
         public Person Assignee { get; set; }
 
-        [NotMapped]
-        [HasManyThrough(nameof(TodoItemTags))]
+        [HasMany]
         public ISet<Tag> Tags { get; set; }
-
-        public ISet<TodoItemTag> TodoItemTags { get; set; }
     }
 }

src/Examples/JsonApiDotNetCoreExample/Models/TodoItemTag.cs

@@ -18,67 +18,38 @@ public interface IResourceGraph : IResourceContextProvider
         /// all exposed fields are returned.
         /// </summary>
         /// <typeparam name="TResource">
-        /// The resource for which to retrieve fields.
+        /// The resource type for which to retrieve fields.
         /// </typeparam>
         /// <param name="selector">
-        /// Should be of the form: (TResource e) => new { e.Field1, e.Field2 }
+        /// Should be of the form: (TResource r) => new { r.Field1, r.Field2 }
         /// </param>
-        IReadOnlyCollection<ResourceFieldAttribute> GetFields<TResource>(Expression<Func<TResource, dynamic>> selector = null)
+        IReadOnlyCollection<ResourceFieldAttribute> GetFields<TResource>(Expression<Func<TResource, dynamic>> selector)
             where TResource : class, IIdentifiable;
 
         /// <summary>
-        /// Gets all attributes for <typeparamref name="TResource" /> that are targeted by the selector. If no selector is provided, all exposed fields are
+        /// Gets all attributes for <typeparamref name="TResource" /> that are targeted by the selector. If no selector is provided, all exposed attributes are
         /// returned.
         /// </summary>
         /// <typeparam name="TResource">
-        /// The resource for which to retrieve attributes.
+        /// The resource type for which to retrieve attributes.
         /// </typeparam>
         /// <param name="selector">
-        /// Should be of the form: (TResource e) => new { e.Attribute1, e.Attribute2 }
+        /// Should be of the form: (TResource r) => new { r.Attribute1, r.Attribute2 }
         /// </param>
-        IReadOnlyCollection<AttrAttribute> GetAttributes<TResource>(Expression<Func<TResource, dynamic>> selector = null)
+        IReadOnlyCollection<AttrAttribute> GetAttributes<TResource>(Expression<Func<TResource, dynamic>> selector)
             where TResource : class, IIdentifiable;
 
         /// <summary>
-        /// Gets all relationships for <typeparamref name="TResource" /> that are targeted by the selector. If no selector is provided, all exposed fields are
-        /// returned.
+        /// Gets all relationships for <typeparamref name="TResource" /> that are targeted by the selector. If no selector is provided, all exposed relationships
+        /// are returned.
         /// </summary>
         /// <typeparam name="TResource">
-        /// The resource for which to retrieve relationships.
+        /// The resource type for which to retrieve relationships.
         /// </typeparam>
         /// <param name="selector">
-        /// Should be of the form: (TResource e) => new { e.Relationship1, e.Relationship2 }
+        /// Should be of the form: (TResource r) => new { r.Relationship1, r.Relationship2 }
         /// </param>
-        IReadOnlyCollection<RelationshipAttribute> GetRelationships<TResource>(Expression<Func<TResource, dynamic>> selector = null)
+        IReadOnlyCollection<RelationshipAttribute> GetRelationships<TResource>(Expression<Func<TResource, dynamic>> selector)
             where TResource : class, IIdentifiable;
-
-        /// <summary>
-        /// Gets all exposed fields (attributes and relationships) for the specified type.
-        /// </summary>
-        /// <param name="type">
-        /// The resource type. Must implement <see cref="IIdentifiable" />.
-        /// </param>
-        IReadOnlyCollection<ResourceFieldAttribute> GetFields(Type type);
-
-        /// <summary>
-        /// Gets all exposed attributes for the specified type.
-        /// </summary>
-        /// <param name="type">
-        /// The resource type. Must implement <see cref="IIdentifiable" />.
-        /// </param>
-        IReadOnlyCollection<AttrAttribute> GetAttributes(Type type);
-
-        /// <summary>
-        /// Gets all exposed relationships for the specified type.
-        /// </summary>
-        /// <param name="type">
-        /// The resource type. Must implement <see cref="IIdentifiable" />.
-        /// </param>
-        IReadOnlyCollection<RelationshipAttribute> GetRelationships(Type type);
-
-        /// <summary>
-        /// Traverses the resource graph, looking for the inverse relationship of the specified <paramref name="relationship" />.
-        /// </summary>
-        RelationshipAttribute GetInverseRelationship(RelationshipAttribute relationship);
     }
 }

src/JsonApiDotNetCore/Configuration/IResourceGraph.cs

@@ -1,4 +1,5 @@
 using System.Collections.Generic;
+using System.Linq;
 using JetBrains.Annotations;
 using JsonApiDotNetCore.Repositories;
 using JsonApiDotNetCore.Resources.Annotations;
@@ -9,7 +10,7 @@ namespace JsonApiDotNetCore.Configuration
 {
     /// <inheritdoc />
     [PublicAPI]
-    public class InverseNavigationResolver : IInverseNavigationResolver
+    public sealed class InverseNavigationResolver : IInverseNavigationResolver
     {
         private readonly IResourceContextProvider _resourceContextProvider;
         private readonly IEnumerable<IDbContextResolver> _dbContextResolvers;
@@ -35,25 +36,37 @@ public void Resolve()
 
         private void Resolve(DbContext dbContext)
         {
-            foreach (ResourceContext resourceContext in _resourceContextProvider.GetResourceContexts())
+            foreach (ResourceContext resourceContext in _resourceContextProvider.GetResourceContexts().Where(context => context.Relationships.Any()))
             {
                 IEntityType entityType = dbContext.Model.FindEntityType(resourceContext.ResourceType);
 
                 if (entityType != null)
                 {
-                    ResolveRelationships(resourceContext.Relationships, entityType);
+                    IDictionary<string, INavigationBase> navigationMap = GetNavigations(entityType);
+                    ResolveRelationships(resourceContext.Relationships, navigationMap);
                 }
             }
         }
 
-        private void ResolveRelationships(IReadOnlyCollection<RelationshipAttribute> relationships, IEntityType entityType)
+        private static IDictionary<string, INavigationBase> GetNavigations(IEntityType entityType)
+        {
+            // @formatter:wrap_chained_method_calls chop_always
+
+            return entityType.GetNavigations()
+                .Cast<INavigationBase>()
+                .Concat(entityType.GetSkipNavigations())
+                .ToDictionary(navigation => navigation.Name);
+
+            // @formatter:wrap_chained_method_calls restore
+        }
+
+        private void ResolveRelationships(IReadOnlyCollection<RelationshipAttribute> relationships, IDictionary<string, INavigationBase> navigationMap)
         {
             foreach (RelationshipAttribute relationship in relationships)
             {
-                if (!(relationship is HasManyThroughAttribute))
+                if (navigationMap.TryGetValue(relationship.Property.Name, out INavigationBase navigation))
                 {
-                    INavigation inverseNavigation = entityType.FindNavigation(relationship.Property.Name)?.Inverse;
-                    relationship.InverseNavigationProperty = inverseNavigation?.PropertyInfo;
+                    relationship.InverseNavigationProperty = navigation.Inverse?.PropertyInfo;
                 }
             }
         }

src/JsonApiDotNetCore/Configuration/InverseNavigationResolver.cs

@@ -18,6 +18,7 @@
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.EntityFrameworkCore.Metadata;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.DependencyInjection.Extensions;
 using Microsoft.Extensions.Logging;
@@ -51,7 +52,7 @@ public JsonApiApplicationBuilder(IServiceCollection services, IMvcCoreBuilder mv
             var loggerFactory = _intermediateProvider.GetRequiredService<ILoggerFactory>();
 
             _resourceGraphBuilder = new ResourceGraphBuilder(_options, loggerFactory);
-            _serviceDiscoveryFacade = new ServiceDiscoveryFacade(_services, _resourceGraphBuilder, _options, loggerFactory);
+            _serviceDiscoveryFacade = new ServiceDiscoveryFacade(_services, _resourceGraphBuilder, loggerFactory);
         }
 
         /// <summary>
@@ -283,7 +284,12 @@ private void AddResourcesFromDbContext(DbContext dbContext, ResourceGraphBuilder
         {
             foreach (IEntityType entityType in dbContext.Model.GetEntityTypes())
             {
-                builder.Add(entityType.ClrType);
+#pragma warning disable EF1001 // Internal EF Core API usage.
+                if (entityType is not EntityType { IsImplicitlyCreatedJoinEntityType: true })
+#pragma warning restore EF1001 // Internal EF Core API usage.
+                {
+                    builder.Add(entityType.ClrType);
+                }
             }
         }