asp.net – 在MVC5应用程序中使用OWIN软件包的好处

是的,您可能会跳过很多不必要的事情,因为您将在管道中定义组件,以及使用您的应用程序将使用的不一定由您制定的其他组件.这些组件是中间件,因为它们位于处理流水线的中间,组件可以决定通过async / await C#语法将控制权传递给流水线中的下一个组件,或者结束该组件的处理.

AppGroup对象是Katana发生“魔术”的地方,因为它是调用组件使用的逻辑,签名是这样的：

Func<IDictionary<string,object>,Task>;

Note: The IDictionary<string,object> represents the environment values (such as Request and Response; think HttpContext in ASP.NET) and the OWIN standard defines certain values that must exist in this dictionary,such as "owin.RequestBody" or "owin.ResponseBody". Katana is Microsoft’s implementation of the OWIN standard and as such has these,and other,dictionary items available out-of-the-box.

组件的一个例子将是一个匹配AppFunc的签名的方法(它是Func< IDictionary< string,Task>,像这样：

public async Task Invoke(IDictionary<string,object> environment)
{
    // Do processing...

    // Wait for next component to complete
    await _nextComponent(environment);

    // Do more processing...
}

Note: OWIN expects the method to return a Task or generate an exception,so return null; would be invalid.

那么你怎么知道下一个组件是什么呢？

您的组件的构造函数需要接受Func< IDictionary< string,Task>的参数,如下所示：

public class HelloWorldCOmponent
{
    Func<IDictionary<string,Task> _next;

    public HelloWorldComponent(Func<IDictionary<string,Task> next)
    {
        _next = next;
    }

    public async Task Invoke(IDictionary<string,object> environment)
    {
        // Do something

        // Wait for next component to return
        await _next(environment);
    }
}