asp.net mvc core 管道以及拦截器初了解
- 2020 年 3 月 12 日
- 筆記
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 executingr"); } 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. rn"); await next(); await context.HttpContext.Response.WriteAsync($"async resource filter out. rn"); } }
3）ActionFilter：在调用操作方法之前和之后立即运行代码；可以更改传递到操作中的参数；可以更改从操作返回的结果。
同步用法：
public class ActionFilter: IActionFilter { public void OnActionExecuting(ActionExecutingContext context) { context.HttpContext.Response.WriteAsync($"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. rn"); await next(); await context.HttpContext.Response.WriteAsync($"async action execution out. rn"); }
4）OnException：在向响应正文写入任何内容之前，对声明处理的异常应用变量策略。
同步用法：
public class ExceptionFilter: IExceptionFilter { public void OnException(ExceptionContext context) { context.HttpContext.Response.WriteAsync($"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 executingr"); } 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
原创，转载注明出处。
