中间件

internal class Program
{
static async Task Main(string[] args)
{
var appBuilder = new AppBuilder();

appBuilder.Use(next =>
{
return async context =>
{
Console.WriteLine("中间件1 开始");
await next(context);
Console.WriteLine("中间件1 结束");
};
});

appBuilder.Use(next =>
{
return async context =>
{
Console.WriteLine("中间件2 开始");
//await next(context);
Console.WriteLine("中间件2 结束");
};
});

var app = appBuilder.Build();
await app(new HttpContext());

Console.ReadLine();
}
}

public class HttpContext
{

}

public delegate Task RequestDelegate(HttpContext context);

public class AppBuilder
{
private IList<Func<RequestDelegate, RequestDelegate>> _components = new List<Func<RequestDelegate, RequestDelegate>>();

public AppBuilder Use(Func<RequestDelegate, RequestDelegate> middleware)
{
_components.Add(middleware);
return this;
}

public RequestDelegate Build()
{
RequestDelegate app = context =>
{
Console.WriteLine("404");
return Task.CompletedTask;
};

foreach (var component in _components.Reverse())
{
app = component(app);
}

return app;
}
}