今天来看一下 ASP.NET core 的执行管道. 先看下官方说明:
从上图可以抛光, ASP.NET core 的执行顺序是, 当收到一个请求后, request 请求会先经过已注册的中间件, 然后会进入到 mvc 的拦截器管道:
进入 mvc 管道后, 根据以上顺序执行过滤校正.
OK, 根据以上说明下面我们新建一个 MVC 的演示, 将执行方式切换为控台运行:
- // This method gets called by the runtime. Use this method to add services to the container.
- public void ConfigureServices(IServiceCollection services)
- {
- services.AddControllersWithViews(config=>
- {
- Console.WriteLine("execute C");
- //config.Filters.Add(new AsyncAuthorizationFilter());
- config.Filters.Add(new AuthorizationFilter());
- config.Filters.Add(new ResourceFilter());
- //config.Filters.Add(new AsyncResourceFilter());
- config.Filters.Add(new ActionFilter());
- //config.Filters.Add(new AsyncActionFilter());
- config.Filters.Add(new ResultFilter());
- //config.Filters.Add(new AsyncResultFilter());
- config.Filters.Add(new ExceptionFilter());
- //config.Filters.Add(new AsyncExceptionFilter());
- Console.WriteLine("execute D");
- });
- services.AddSession(config=> {
- Console.WriteLine("execute E");
- });
- }
- // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
- public void Configure(IApplicationBuilder App, IwebHostEnvironment env)
- {
- if (env.IsDevelopment())
- {
- App.UseDeveloperExceptionPage();
- }
- else
- {
- App.UseExceptionHandler("/Home/Error");
- }
- App.UseStaticFiles();
- App.UseRouting();
- App.UseAuthorization();
- App.Use(async (context, next) =>
- {
- Console.WriteLine("execute F");
- await context.Response.WriteAsync("hello world");
- Console.WriteLine("execute G");
- });
- //App.UseSession();
- App.UseEndpoints(endpoints =>
- {
- Console.WriteLine("execute A");
- endpoints.MapControllerRoute(
- name: "default",
- pattern: "{controller=Home}/{action=Index}/{id?}");
- Console.WriteLine("execute B");
- });
- }
执行结果:
不多做解释, 从从这里我们可以抛光符合官方说明文档.
看完中间件执行顺序, 下面我们来了解下 mvc 拦截器的使用与执行顺序.
根据 mvc filter 管道执行顺序, 我们分别来看下用法:
1)AuthorizationFilter: 该拦截器是优先级最高的, 当请求进入 mvc 后, 首先会被 AuthorizationFilter 验证是否有权限访问, 无权限则跳出.
同步用法:
- public class AuthorizationFilter: IAuthorizationFilter
- {
- public void OnAuthorization(AuthorizationFilterContext context)
- {
- context.HttpContext.Response.WriteAsync("authorization filter \r");
- }
- }
异步用法:
- public class AsyncAuthorizationFilter: IAsyncAuthorizationFilter
- {
- public async Task OnAuthorizationAsync(AuthorizationFilterContext context)
- {
- await context.HttpContext.Response.WriteAsync($"async authorization filter in \r");
- }
- }
2)ResourceFilter: 该拦截器是作为第二道拦截器,
OnResourceExecuting 在模型绑定之前运行代码. OnResourceExecuted 在管道的其余阶段完成之后运行代码.
同步用法:
- public class ResourceFilter: IResourceFilter
- {
- public void OnResourceExecuting(ResourceExecutingContext context)
- {
- context.HttpContext.Response.WriteAsync($"resource executing\r");
- }
- public void OnResourceExecuted(ResourceExecutedContext context)
- {
- context.HttpContext.Response.WriteAsync($"resource executed \r");
- }
- }
异步用法:
- public class AsyncResourceFilter: IAsyncResourceFilter
- {
- public async Task OnResourceExecutionAsync(ResourceExecutingContext context, ResourceExecutionDelegate next)
- {
- await context.HttpContext.Response.WriteAsync($"async resource filter in. \r\n");
- await next();
- await context.HttpContext.Response.WriteAsync($"async resource filter out. \r\n");
- }
- }
3)ActionFilter: 在调用操作方法之前和之后立即运行代码; 可以更改传递到操作中的参数; 可以更改从操作返回的结果.
同步用法:
- public class ActionFilter: IActionFilter
- {
- public void OnActionExecuting(ActionExecutingContext context)
- {
- context.HttpContext.Response.WriteAsync($"action executing \r");
- }
- public void OnActionExecuted(ActionExecutedContext context)
- {
- context.HttpContext.Response.WriteAsync($"action executed . \r");
- }
- }
异步用法:
- public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next)
- {
- await context.HttpContext.Response.WriteAsync($"async action execution in. \r\n");
- await next();
- await context.HttpContext.Response.WriteAsync($"async action execution out. \r\n");
- }
4)OnException: 在向响应正文写入任何内容之前, 对声明处理的异常应用变量策略.
同步用法:
- public class ExceptionFilter: IExceptionFilter
- {
- public void OnException(ExceptionContext context)
- {
- context.HttpContext.Response.WriteAsync($"exception \r");
- }
- }
异步用法:
- public class AsyncExceptionFilter: IAsyncExceptionFilter
- {
- public Task OnExceptionAsync(ExceptionContext context)
- {
- context.HttpContext.Response.WriteAsync($"exception async \r");
- return Task.CompletedTask;
- }
- }
5)ResultFilter: 在执行操作结果之前和之后立即运行代码; 仅当操作方法成功执行时, 其才会运行. 可以设置格式化返回结果:
同步操作:
- public class ResultFilter: IResultFilter
- {
- public void OnResultExecuting(ResultExecutingContext context)
- {
- context.HttpContext.Response.WriteAsync($"result executing\r");
- }
- public void OnResultExecuted(ResultExecutedContext context)
- {
- context.HttpContext.Response.WriteAsync($"result executed \r");
- }
- }
异步用法:
- public class AsyncResultFilter: IAsyncResultFilter
- {
- public async Task OnResultExecutionAsync(ResultExecutingContext context, ResultExecutionDelegate next)
- {
- await context.HttpContext.Response.WriteAsync($"result execution async in \r");
- await next();
- await context.HttpContext.Response.WriteAsync($"result execution async out. \r");
- }
- }
注册方式我们就是用分区注册, 已经在上面说明, 不再多做表述, 下面我们看下运行情况 (页面输出):
定义一个异常看下结果:
- public IActionResult Privacy()
- {
- throw new Exception("error");
- }
ok, 目标达成, 不多说了, 下次再看拦截器具体实现.
参考文档: ASP.NET Core 中的筛选器
来源: https://www.cnblogs.com/xtt321/p/12467142.html