Merge pull request #14 from darxis/dev

Release 1.1.1-beta3

Author: darxis

.travis.yml

@@ -0,0 +1,23 @@
+language: csharp
+solution: EntityFramework.LazyLoading.sln
+mono: none
+dotnet: 1.0.1
+dist: trusty
+sudo: required
+services:
+  - mysql
+  - postgresql
+env:
+  global:
+    - DB_NAME=ContosoUniversity
+  matrix:
+    - DB=PostgreSql CONFIGURATION=Release
+    #- DB=MySql CONFIGURATION=Release
+install:
+  - dotnet restore
+before_script:
+  - export Microsoft_EntityFrameworkCore_LazyLoading_Tests_DatabaseType=$DB 
+  #- sh -c "if [ '$DB' = 'MySql' ]; then mysql -e 'CREATE DATABASE \`$DB_NAME\`; USE \`$DB_NAME\`; CREATE TABLE \`__EFMigrationsHistory\` (\`MigrationId\` nvarchar(150) NOT NULL, \`ProductVersion\` nvarchar(32) NOT NULL, PRIMARY KEY (\`MigrationId\`));'; (cd tests/Microsoft.EntityFrameworkCore.LazyLoading.Tests && dotnet ef database update); fi"
+script:
+  - dotnet build --configuration $CONFIGURATION
+  - (cd tests/Microsoft.EntityFrameworkCore.LazyLoading.Tests && dotnet test --configuration $CONFIGURATION)

README.md

@@ -1,12 +1,18 @@
-# EntityFramework.LazyLoading
+# EntityFramework.LazyLoading [![Build Status](https://travis-ci.org/darxis/EntityFramework.LazyLoading.svg?branch=dev)](https://travis-ci.org/darxis/EntityFramework.LazyLoading)
 Lazy Loading for EF Core
 
 Inspired by and partially based on the blog post: https://weblogs.asp.net/ricardoperes/implementing-missing-features-in-entity-framework-core-part-6-lazy-loading
 
 # How to enable LazyLoading in EF Core?
 
-1. Reference the `Microsoft.EntityFrameworkCore.LazyLoading` NuGet package (https://www.nuget.org/packages/Microsoft.EntityFrameworkCore.LazyLoading/).
-2. Create (or modify an existing) DbContext factory. Include the lines inside the two `if(_isLazy)` blocks in your DbContext factory (3 lines total - 2 before building the DbContext, and 1 after):
+Enabling LazyLoading in EF Core is extremely easy with this library. You just need to call `UseLazyLoading()` (see step 2 below).
+
+However, you will need to slightly modify your entity classes, but just the References, not the Collections (see step 3 below).
+
+## Step 1 - Nuget package
+Reference the `Microsoft.EntityFrameworkCore.LazyLoading` NuGet package (https://www.nuget.org/packages/Microsoft.EntityFrameworkCore.LazyLoading/).
+## Step 2 - Configure the DbContext builder
+Call `UseLazyLoading()` on the `DbContextOptionsBuilder` when creating the `DbContext`.
 ```c#
 public class MyDbContextFactory : IDbContextFactory<MyDbContext>
 {
@@ -22,30 +28,15 @@ public class MyDbContextFactory : IDbContextFactory<MyDbContext>
         var dbContextOptionsBuilder = new DbContextOptionsBuilder<MyDbContext>();
         dbContextOptionsBuilder.UseSqlServer("<some_connection_string>");
 
-        // LazyLoading specific
-        if (_isLazy)
-        {
-            dbContextOptionsBuilder.ReplaceService<Microsoft.EntityFrameworkCore.Metadata.Internal.IEntityMaterializerSource, Microsoft.EntityFrameworkCore.LazyLoading.Metadata.Internal.LazyLoadingEntityMaterializerSource<MyDbContext>>();
-            dbContextOptionsBuilder.ReplaceService<Microsoft.EntityFrameworkCore.Internal.IConcurrencyDetector, Microsoft.EntityFrameworkCore.LazyLoading.Internal.ConcurrencyDetector>();
-            dbContextOptionsBuilder.ReplaceService<Microsoft.EntityFrameworkCore.Query.Internal.ICompiledQueryCache, Microsoft.EntityFrameworkCore.LazyLoading.Query.Internal.PerDbContextCompiledQueryCache>();
-        }
-            
-
-        // Build DbContext
-        var ctx = new MyDbContext(dbContextOptionsBuilder.Options);
-
-        // LazyLoading specific
-        if (_isLazy)
-        {
-            (ctx.GetService<Microsoft.EntityFrameworkCore.Metadata.Internal.IEntityMaterializerSource>() as Microsoft.EntityFrameworkCore.LazyLoading.Metadata.Internal.LazyLoadingEntityMaterializerSource<MyDbContext>).SetDbContext(ctx);
-            (ctx.GetService<Microsoft.EntityFrameworkCore.Query.Internal.ICompiledQueryCache>() as Microsoft.EntityFrameworkCore.LazyLoading.Query.Internal.PerDbContextCompiledQueryCache).SetDbContext(ctx);
-        }
+        // Here we enable LazyLoading
+        dbContextOptionsBuilder.UseLazyLoading();
 
-        return ctx;
+        return new MyDbContext(dbContextOptionsBuilder.Options);
     }
 }
 ```
-3. In your model you need to declare References using the type LazyReference<T>. Collections don't require additional configuration in your model, just use the ICollection<> type.
+## Step 3 - Adjust the model
+In your model you need to declare References using the type `LazyReference<T>`. Collections don't require additional configuration in your model, just use the `ICollection<>` type.
 ```c#
 public class Parent
 {
@@ -68,4 +59,5 @@ public class Child
     }
 }
 ```
-4. That's all, LazyLoading enabled.
+## Step 4 - Done!
+That's all, LazyLoading enabled! It was so easy, wasn't it?

samples/Microsoft.EntityFrameworkCore.LazyLoading.Sample/Data/Factory/SchoolContextFactory.cs

@@ -1,9 +1,4 @@
 using Microsoft.EntityFrameworkCore.Infrastructure;
-using Microsoft.EntityFrameworkCore.Metadata.Internal;
-using Microsoft.EntityFrameworkCore.LazyLoading.Internal;
-using Microsoft.EntityFrameworkCore.LazyLoading.Metadata.Internal;
-using Microsoft.EntityFrameworkCore.LazyLoading.Query.Internal;
-using Microsoft.EntityFrameworkCore.Query.Internal;
 
 namespace Microsoft.EntityFrameworkCore.LazyLoading.Sample.Data.Factory
 {
@@ -23,28 +18,17 @@ public SchoolContextFactory(bool isLazy)
         public SchoolContext Create(DbContextFactoryOptions options)
         {
             var dbContextOptionsBuilder = new DbContextOptionsBuilder<SchoolContext>();
+
             dbContextOptionsBuilder.UseSqlServer("Server=(localdb)\\mssqllocaldb;Database=ContosoUniversity;Trusted_Connection=True;MultipleActiveResultSets=true");
 
             // LazyLoading specific
             if (_isLazy)
             {
-                dbContextOptionsBuilder.ReplaceService<IEntityMaterializerSource, LazyLoadingEntityMaterializerSource<SchoolContext>>();
-                dbContextOptionsBuilder.ReplaceService<EntityFrameworkCore.Internal.IConcurrencyDetector, ConcurrencyDetector>();
-                dbContextOptionsBuilder.ReplaceService<ICompiledQueryCache, PerDbContextCompiledQueryCache>();
+                dbContextOptionsBuilder.UseLazyLoading();
             }
-            
 
             // Build DbContext
-            var ctx = new SchoolContext(dbContextOptionsBuilder.Options);
-
-            // LazyLoading specific
-            if (_isLazy)
-            {
-                (ctx.GetService<IEntityMaterializerSource>() as LazyLoadingEntityMaterializerSource<SchoolContext>).SetDbContext(ctx);
-                (ctx.GetService<ICompiledQueryCache>() as PerDbContextCompiledQueryCache).SetDbContext(ctx);
-            }
-
-            return ctx;
+            return new SchoolContext(dbContextOptionsBuilder.Options);
         }
     }
 }

samples/Microsoft.EntityFrameworkCore.LazyLoading.Sample/Data/SchoolContext.cs

@@ -26,7 +26,10 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
             modelBuilder.Entity<Instructor>();
             modelBuilder.Entity<OfficeAssignment>();
             modelBuilder.Entity<CourseAssignment>();
-            modelBuilder.Entity<Person>();
+            modelBuilder.Entity<Person>()
+                .HasDiscriminator<string>("Discriminator")
+                .HasValue<Student>(nameof(Student))
+                .HasValue<Instructor>(nameof(Instructor));
 
             modelBuilder.Entity<CourseAssignment>()
                 .HasKey(c => new { c.CourseID, c.InstructorID });

samples/Microsoft.EntityFrameworkCore.LazyLoading.Sample/Program.cs

@@ -9,6 +9,8 @@ namespace Microsoft.EntityFrameworkCore.LazyLoading.Sample
 {
     class Program
     {
+        // ReSharper disable once UnusedMember.Local
+        // ReSharper disable once UnusedParameter.Local
         static void Main(string[] args)
         {
             var lazyFactory = new SchoolContextFactory(true);
@@ -47,8 +49,9 @@ static void Main(string[] args)
                 var student = dbContext.Students.First();
                 try
                 {
+                    // ReSharper disable once UnusedVariable
                     var deptName = student.Enrollments.First().Course.Department.Name;
-                    Console.WriteLine($"Oops... Something didn't work. LazyLoading should not be enabled by default.");
+                    Console.WriteLine("Oops... Something didn't work. LazyLoading should not be enabled by default.");
                 }
                 catch (ArgumentNullException)
                 {

src/Microsoft.EntityFrameworkCore.LazyLoading/Infrastructure/Internal/LazyLoadingOptionsExtension.cs

@@ -0,0 +1,31 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.LazyLoading.Internal;
+using Microsoft.EntityFrameworkCore.LazyLoading.Metadata.Internal;
+using Microsoft.EntityFrameworkCore.LazyLoading.Query.Internal;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
+using Microsoft.EntityFrameworkCore.Query.Internal;
+using Microsoft.Extensions.DependencyInjection;
+
+namespace Microsoft.EntityFrameworkCore.LazyLoading.Infrastructure.Internal
+{
+    public class LazyLoadingOptionsExtension : IDbContextOptionsExtension
+    {
+        public LazyLoadingOptionsExtension()
+        {
+        }
+
+        // NB: When adding new options, make sure to update the copy ctor below.
+
+        // ReSharper disable once UnusedParameter.Local
+        public LazyLoadingOptionsExtension(LazyLoadingOptionsExtension copyFrom)
+        {
+        }
+
+        public void ApplyServices(IServiceCollection services)
+        {
+            services.AddScoped<IEntityMaterializerSource, LazyLoadingEntityMaterializerSource>();
+            services.AddScoped<EntityFrameworkCore.Internal.IConcurrencyDetector, ConcurrencyDetector>();
+            services.AddScoped<ICompiledQueryCache, PerDbContextCompiledQueryCache>();
+        }
+    }
+}

src/Microsoft.EntityFrameworkCore.LazyLoading/LazyCollection.cs

@@ -15,7 +15,7 @@ public sealed class LazyCollection<T> : IList<T>
         private readonly DbContext _ctx;
         private readonly string _collectionName;
         private readonly object _parent;
-        private readonly IList<T> _entries = new List<T>();
+        private IList<T> _entries = new List<T>();
 
         public LazyCollection(DbContext ctx, object parent, string collectionName)
         {
@@ -26,48 +26,41 @@ public LazyCollection(DbContext ctx, object parent, string collectionName)
 
         private void EnsureLoaded()
         {
-            if (!_loaded && !_loading)
+            if (_loaded || _loading)
             {
-                _loading = true;
+                return;
+            }
+
+            _loading = true;
 
-                var concurrencyDetector = _ctx.GetService<EntityFrameworkCore.Internal.IConcurrencyDetector>() as IConcurrencyDetector;
+            try
+            {
+                var concurrencyDetector =
+                    _ctx.GetService<EntityFrameworkCore.Internal.IConcurrencyDetector>() as IConcurrencyDetector;
                 if (concurrencyDetector == null)
                 {
-                    _loading = false;
-                    throw new LazyLoadingConfigurationException($"Service of type '{typeof(EntityFrameworkCore.Internal.IConcurrencyDetector).FullName}' must be replaced by a service of type '{typeof(IConcurrencyDetector).FullName}' in order to use LazyLoading");
+                    throw new LazyLoadingConfigurationException(
+                        $"Service of type '{typeof(EntityFrameworkCore.Internal.IConcurrencyDetector).FullName}' must be replaced by a service of type '{typeof(IConcurrencyDetector).FullName}' in order to use LazyLoading");
                 }
 
                 if (concurrencyDetector.IsInOperation())
                 {
-                    _loading = false;
                     return;
                 }
 
-                var entries = _ctx
+                _entries = _ctx
                     .Entry(_parent)
                     .Collection(_collectionName)
                     .Query()
                     .OfType<T>()
                     .ToList();
-
-                /*if (typeof(ILazyLoading).IsAssignableFrom(typeof(T)))
-                {
-                    foreach (var entry in entries)
-                    {
-                        ((ILazyLoading)entry).UseLazyLoading(_ctx);
-                    }
-                }*/
-
-                _entries.Clear();
-
-                foreach (var entry in entries)
-                {
-                    _entries.Add(entry);
-                }
-
-                _loaded = true;
+            }
+            finally
+            {
                 _loading = false;
             }
+
+            _loaded = true;
         }
 
         IEnumerator<T> IEnumerable<T>.GetEnumerator()
@@ -161,11 +154,5 @@ public override string ToString()
             EnsureLoaded();
             return _entries.ToString();
         }
-
-        public override int GetHashCode()
-        {
-            EnsureLoaded();
-            return _entries.GetHashCode();
-        }
     }
 }

src/Microsoft.EntityFrameworkCore.LazyLoading/LazyLoadingDbContextOptionsBuilderExtensions.cs

@@ -0,0 +1,30 @@
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.LazyLoading.Infrastructure.Internal;
+
+// ReSharper disable once CheckNamespace
+namespace Microsoft.EntityFrameworkCore
+{
+    public static class LazyLoadingDbContextOptionsBuilderExtensions
+    {
+        public static DbContextOptionsBuilder UseLazyLoading(this DbContextOptionsBuilder optionsBuilder)
+        {
+            var extension = GetOrCreateExtension(optionsBuilder);
+            ((IDbContextOptionsBuilderInfrastructure) optionsBuilder).AddOrUpdateExtension(extension);
+
+            return optionsBuilder;
+        }
+
+        public static DbContextOptionsBuilder<TContext> UseLazyLoading<TContext>(
+            this DbContextOptionsBuilder<TContext> optionsBuilder)
+            where TContext : DbContext
+            => (DbContextOptionsBuilder<TContext>) UseLazyLoading((DbContextOptionsBuilder) optionsBuilder);
+
+        private static LazyLoadingOptionsExtension GetOrCreateExtension(DbContextOptionsBuilder optionsBuilder)
+        {
+            var existing = optionsBuilder.Options.FindExtension<LazyLoadingOptionsExtension>();
+            return existing != null
+                ? new LazyLoadingOptionsExtension(existing)
+                : new LazyLoadingOptionsExtension();
+        }
+    }
+}

src/Microsoft.EntityFrameworkCore.LazyLoading/LazyReference.cs

@@ -28,25 +28,32 @@ public void SetValue(T value)
 
         public T GetValue(object parent, string referenceName)
         {
-            if (_ctx != null && !_isLoaded && !_isLoading)
+            if (_ctx == null || _isLoaded || _isLoading)
             {
-                _isLoading = true;
+                return _value;
+            }
+
+            _isLoading = true;
 
-                var concurrencyDetector = _ctx.GetService<EntityFrameworkCore.Internal.IConcurrencyDetector>() as IConcurrencyDetector;
+            try
+            {
+                var concurrencyDetector =
+                    _ctx.GetService<EntityFrameworkCore.Internal.IConcurrencyDetector>() as IConcurrencyDetector;
                 if (concurrencyDetector == null)
                 {
-                    _isLoading = false;
-                    throw new LazyLoadingConfigurationException($"Service of type '{typeof(EntityFrameworkCore.Internal.IConcurrencyDetector).FullName}' must be replaced by a service of type '{typeof(IConcurrencyDetector).FullName}' in order to use LazyLoading");
+                    throw new LazyLoadingConfigurationException(
+                        $"Service of type '{typeof(EntityFrameworkCore.Internal.IConcurrencyDetector).FullName}' must be replaced by a service of type '{typeof(IConcurrencyDetector).FullName}' in order to use LazyLoading");
                 }
 
                 if (concurrencyDetector.IsInOperation())
                 {
-                    _isLoading = false;
                     return _value;
                 }
 
                 _ctx.Entry(parent).Reference(referenceName).Load();
-
+            }
+            finally
+            {
                 _isLoading = false;
             }
 

src/Microsoft.EntityFrameworkCore.LazyLoading/Metadata/Internal/ILazyLoadingEntityMaterializerSource.cs

@@ -1,8 +1,6 @@
 namespace Microsoft.EntityFrameworkCore.LazyLoading.Metadata.Internal
 {
-    public interface ILazyLoadingEntityMaterializerSource<in TDbContext>
-        where TDbContext : DbContext
+    public interface ILazyLoadingEntityMaterializerSource
     {
-        void SetDbContext(TDbContext ctx);
     }
 }