7. Dependency injection

Register as agreed

Masa It introduces service registration according to the contract , According to the Convention, it is greater than the configuration , Developers don't have to do anything , The framework will automatically complete the registration

Dependent interface

• ISingletonDependency:  The registration life cycle is Singleton Service for

• IScopedDependency:  The registration life cycle is Scoped Service for

• ITransientDependency:  The registration life cycle is Transient Service for

• IAutoFireDependency:  Automatic triggering （ And ISingletonDependency、IScopedDependency、ITransientDependency Use a combination of , After the automatic registration of the service is completed, a get service operation is triggered , Just inherit IAutoFireDependency It doesn't work ）

Example ：

 public class StorageOptions : ITransientDependency
 {
 
 }


characteristic

IgnoreInjection

Ignore injection , Used to exclude not being automatically injected

• Cascade:  Set to true when , The current class and subclasses are no longer automatically registered , Set to false, Only the current class is not automatically registered （ Default false）

Example ：

 public class BaseService : ISingletonDependency
 {
 public static int Count { get; set; } = 0;
 
 public BaseService()
 {
 Count++;
 }
 
 public BaseService(bool isChildren)
 {
 
 }
 }

 [IgnoreInjection]
 public class GoodsBaseService : BaseService
 {
 public GoodsBaseService() : base(true)
 {
 }
 }

 public class GoodsService : GoodsBaseService
 {
 public static int GoodsCount { get; set; } = 0;
 
 public GoodsService()
 {
 GoodsCount++;
 }
 }


The effect is equivalent to ：services.AddSingleton<

BaseService

>(); services.AddSingleton<

GoodsService

>();

Dependency

coordination ISingletonDependency、IScopedDependency、ITransientDependency Use , The implementation service is registered only once

• TryRegister:  Set up true Then the service will only be registered if it is not registered , similar IServiceCollection Of TryAdd ...  Extension method .

Example ：

 public interface ICache : ISingletonDependency
 {
 void Set(string key, string value);
 }

 [Dependency(TryRegister = true)]
 public class EmptyCache : ICache
 {
 public void Set(string key, string value)
 {
 throw new NotSupportedException($" Temporary does not support {nameof(Set)} Method ");
 }
 }

 public class MemoryCache : ICache
 {
 private readonly ConcurrentDictionary<string, Lazy<string>> _dicCache = new();
 
 public void Set(string key, string value)
 {
 _ = _dicCache.AddOrUpdate
 (
 key,
 k => new Lazy<string>(() => value, LazyThreadSafetyMode.ExecutionAndPublication),
 (_, _) => new Lazy<string>(() => value, LazyThreadSafetyMode.ExecutionAndPublication)
 ).Value;
 }
 }


The effect is equivalent to ：services.AddSingleton<

ICache

, 

MemoryCache

>();

• ReplaceServices:  Set up true Then replace the previously registered service , similar IServiceCollection Of Replace ...  Extension method .

Example ：

 public interface IEncryptionService : ISingletonDependency
 {
 string MethodName { get; }
 }

 [Dependency(ReplaceServices = true)]
 public class Sha1EncryptionService : IEncryptionService
 {
 public string MethodName => "Sha1";
 }

 public class Md5EncryptionService : IEncryptionService
 {
 public string MethodName => "Md5";
 }


The effect is equivalent to ：services.AddSingleton<

IEncryptionService

, 

Sha1EncryptionService

>();

Quick start

• install
  .Net 6.0

• New unit test project
  Assignment.DependencyInjection
  , choice
  MSTest
  , And install
  Masa.Utils.Extensions.DependencyInjection

 dotnet new xunit -o Assignment.DependencyInjection
 cd Assignment.DependencyInjection
 dotnet add package Masa.Utils.Extensions.DependencyInjection --version 0.5.0-preview.2


• The new class
  StorageOptions

 public class StorageOptions : ITransientDependency
 {
 
 }


• The new class
  DITest

 [TestClass]
 public class DITest
 {
 private IServiceCollection _services;
 
 [TestInitialize]
 public void Init()
 {
 _services = new ServiceCollection();
 _services.AddAutoInject();// Perform automatic injection
 }
 
 [TestMethod]
 public void TestAutoInject()
 {
 Assert.IsTrue(_services.Any<StorageOptions>(ServiceLifetime.Transient));// Judge StorageOptions Registered successfully , And the life cycle is Transient
 }
 
 private IServiceProvider ServiceProvider => _services.BuildServiceProvider();
 }


summary

If you need to use the automatic registration service according to the contract , Please remember

• According to business needs , Then the following interfaces are implemented in the specified class or interface

• ISingletonDependency
    Single case （ Only initialize once after the project is started ）

• IScopedDependency
    request  （ Initialize only once per request ）

• ITransientDependency
    instantaneous （ Each acquisition is initialized ）

• Abstract classes are not automatically registered

• If you have a custom interface
  IRepository
  , And you want the interface and the corresponding default implementation class
  RepositoryBase
  Will be automatically registered with a lifecycle of Scoped, Interface
  IRepository
  Should inherit
  IScopedDependency

• If you want to provide by default
  RepositoryBase
  Can be replaced by user-defined classes , Should be in
  RepositoryBase
  Increase above [Dependency(TryRegister = true)], The user only needs to realize
  IRepository
  that will do

• Or do not change the default
  RepositoryBase
  , User implementation
  IRepository
  after , And add [Dependency(ReplaceServices = true)]

Source code of this chapter

Assignment07

https://github.com/zhenlei520/MasaFramework.Practice

Open source address

MASA.BuildingBlocks：https://github.com/masastack/MASA.BuildingBlocks

MASA.Contrib：https://github.com/masastack/MASA.Contrib

MASA.Utils：https://github.com/masastack/MASA.Utils

MASA.EShop：https://github.com/masalabs/MASA.EShop

MASA.Blazor：https://github.com/BlazorComponent/MASA.Blazor

If you treat our  MASA Framework  Interested in , Whether it's code contribution 、 Use 、 carry  Issue, Welcome to contact us