web api 自托管自定义 ioc 将数据注入控制器

Question

我的 web api 自托管应用程序中有一个属性，我想将它注入到我的控制器中，该属性是使用我的自定义 IoC 框架通过反射加载的，这是我的启动代码：

public CustomClass StuffInstance { get; set; }


// This method is required by Katana:
public void Configuration(IAppBuilder app)
{
    ConfigureOAuth(app);
    var webApiConfiguration = ConfigureWebApi();

    // Use the extension method provided by the WebApi.Owin library:
    app.UseWebApi(webApiConfiguration);
}

我的控制器大多是脚手架，有些像：

// PUT: api/EventTypeDescriptions/5
[ResponseType(typeof(void))]
public IHttpActionResult PutStuff(int id, int something)
{
    //do stuff
    //here i would like to use StuffInstance like a singleton
    return StatusCode(HttpStatusCode.NoContent);
}  

如何将 StuffInstance 注入我的控制器？顺便说一句，此信息将与任何制作 IoC 框架的人相关

Answer 1

我在此链接中找到了将实例注入我的控制器的信息：

http://www.asp.net/web-api/overview/advanced/dependency-injection

基本上我为我的自定义 IoC 库实现了一个依赖解析器

如果有人遇到同样的问题，这里是代码，也许对于其他 IoC 框架它需要更多的工作

public class CustomIocDependencyResolver : IDependencyResolver
{
    private readonly CustomIoc container;

    public ComponentLoaderWebApiDependencyResolver(CustomIoc container)
    {
        this.container = container;
    }

    IDependencyScope IDependencyResolver.BeginScope()
    {
        return new CustomIocDependencyResolver(container);
    }

    Object IDependencyScope.GetService(Type serviceType)
    {
        return container.GetInstance(serviceType);
    }

    IEnumerable<Object> IDependencyScope.GetServices(Type serviceType)
    {
        return container.GetAllInstances(serviceType);
    }

    public void Dispose()
    {
    }
}

现在我的武士刀配置如下：

    // This method is required by Katana:
    public void Configuration(IAppBuilder app)
    {
        ConfigureOAuth(app);
        var config = ConfigureWebApi();

        config.DependencyResolver = CustomIocDependencyResolver(container);

        // Use the extension method provided by the WebApi.Owin library:
        app.UseWebApi(config);
    }

作为我的自定义 IoC 实例的容器

Answer 2

由于您提到 AutoFac 作为潜在候选者，我建议您关注他们的 tutorial 关于 WebAPI 集成。您需要在 CustomClass 上定义一个接口，以便正确注入它。

您需要通过将其注册为实例组件来注入您创建的实例（因为您希望将其视为单例）。

public interface ICustomClass {}
public class CustomClass : ICustomClass {}

public CustomClass _stuffInstance = new CustomClass();

public class Startup
{
    public void Configuration(IAppBuilder app)
    {
        ConfigureOAuth(app);

        var builder = new ContainerBuilder();
        var config = new HttpConfiguration();

        builder.RegisterApiControllers(Assembly.GetExecutingAssembly());

        builder.RegisterInstance(_stuffInstance).As<ICustomClass>();

        var container = builder.Build();
        config.DependencyResolver = new AutofacWebApiDependencyResolver(container);

        app.UseAutofacMiddleware(container);
        app.UseAutofacWebApi(config);
        app.UseWebApi(config);
    }
}

然后，在每个控制器的构造函数中，注入绑定到相应接口的实例。

public class CustomController : ApiController
{
    private readonly ICustomClass _customClass;

    public CustomController(ICustomClass customClass)
    {
        _customClass = customClass;
    }    
}

Answer 3

使用 ASP.NET Core 6，您现在可以注册服务提供者：

builder.Services.AddScoped<ICustomClass, CustomClass>(sp => new CustomClass()/* or your already existing instance */);
builder.Services.AddSingleton<ICustomClass>(sp => new CustomClass()/* or your already existing singleton instance */);

它将被注入到您的控制器中：

[Route("api/[controller]")]
[ApiController]
public class MyController : ControllerBase
{
    private readonly ICustomClass _customClass;
    private readonly ILogger _logger;

    public MyController(ICustomClass customClass, ILogger<MyController> logger)
    {
        _customClass = customClass;
        _logger = logger;
    }