c# - 如何将原始数据传递给 asp.net core 中间件

Question

我需要将一些数据传递到 ASP NET CORE 中间件

例如如果这是一个字符串列表，您是否使用与传入服务相同的机制？

例如将其作为参数添加到 Invoke 方法中并注册到 DI？

如果是这样，你如何注册原始类型？例如一串字符串。它必须是命名类型或类似的东西吗？

或者我们可以通过其他方式传递数据吗？

谢谢

Answer 1

假设我们有一个中间件:

public class FooMiddleware
{
    public FooMiddleware(RequestDelegate next, List<string> list)
    {
        _next = next;
    }
}

只需将列表传递给 UseMiddleware 调用即可per-middleware 解决它:

app.UseMiddleware<FooMiddleware>(new List<string>());

您可以创建一个 DTO 并传递它:

public FooMiddleware(RequestDelegate next, Payload payload)
....
app.UseMiddleware<FooMiddleware>(new Payload());    

或者在DI容器中注册这个DTO，在中间件中解析:

public void ConfigureServices(IServiceCollection services)
{
    services.AddSingleton<Payload>(new Payload());
}

此外，DI 容器允许解析每个请求 依赖项:

public async Task Invoke(HttpContext httpContext, IMyScopedService svc)
{
    svc.MyProperty = 1000;
    await _next(httpContext);
}

Documentation:

Because middleware is constructed at app startup, not per-request, scoped lifetime services used by middleware constructors are not shared with other dependency-injected types during each request. If you must share a scoped service between your middleware and other types, add these services to the Invoke method's signature. The Invoke method can accept additional parameters that are populated by dependency injection.