AspNetCore.AsyncInitialization库源码分析

AspNetCore.AsyncInitialization 这个库是用来实现在asp.net core应用程序启动时异步执行异步任务。可参考：如何在ASP.NET Core程序启动时运行异步任务（2）。IAsyncInitializer接口就是用来实现执行异步任务的接口，此接口签名：

public interface IAsyncInitializer

    {

        /// <summary>

        /// Performs async initialization.

        /// </summary>

        /// <returns>A task that represents the initialization completion.</returns>

        Task InitializeAsync();

    }

默认实现：

private class DelegateAsyncInitializer : IAsyncInitializer

        {

            private readonly Func<Task> _initializer;

            public DelegateAsyncInitializer(Func<Task> initializer)

            {

                _initializer = initializer;

            }

            public Task InitializeAsync()

            {

                return _initializer();

            }

        }

依赖注入：

public static IServiceCollection AddAsyncInitializer(this IServiceCollection services, Func<Task> initializer)

        {

            return services

                .AddAsyncInitialization()

                .AddSingleton<IAsyncInitializer>(new DelegateAsyncInitializer(initializer));

        }

不得不说DelegateAsyncInitializer类的实现比较巧，一般我们是如此的实现IAsyncInitializer接口：

public interface IDependency

        {

        }

        public class Initializer : IAsyncInitializer

        {

            // ReSharper disable once NotAccessedField.Local

            private readonly IDependency _dependency;

            public Initializer(IDependency dependency)

            {

                _dependency = dependency;

            }

            public Task InitializeAsync() => Task.CompletedTask;

        }

相比较这种实现，DelegateAsyncInitializer类的实现更值得借鉴。

AspNetCore.AsyncInitialization库源码分析的相关教程结束。