asp.net mvc core 管道以及攔截器初了解
- 2020 年 3 月 12 日
- 筆記
今天來看一下asp.net core的執行管道。先看下官方說明：
從上圖可以拋光，asp.net core的執行順序是，當收到一個請求後，request請求會先經過已註冊的中間件，然後會進入到mvc的攔截器管道：
進入mvc管道後，根據以上順序執行過濾校正。
OK，根據以上說明下面我們新建一個MVC的演示，將執行方式切換為控台運行：
// 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"); }); }
執行結果：
不多做解釋，從從這裡我們可以拋光符合官方說明文檔。
看完中間件執行順序，下面我們來了解下mvc攔截器的使用與執行順序。
根據mvc filter管道執行順序，我們分別來看下用法：
1）AuthorizationFilter：該攔截器是優先順序最高的，當請求進入mvc後，首先會被AuthorizationFilter驗證是否有許可權訪問，無許可權則跳出。
同步用法：
public class AuthorizationFilter: IAuthorizationFilter { public void OnAuthorization(AuthorizationFilterContext context) { context.HttpContext.Response.WriteAsync("authorization filter r"); } }
非同步用法：
public class AsyncAuthorizationFilter: IAsyncAuthorizationFilter { public async Task OnAuthorizationAsync(AuthorizationFilterContext context) { await context.HttpContext.Response.WriteAsync($"async authorization filter in r"); } }
2）ResourceFilter：該攔截器是作為第二道攔截器，
OnResourceExecuting在模型綁定之前運行程式碼。OnResourceExecuted在管道的其餘階段完成之後運行程式碼。
同步用法：
public class ResourceFilter: IResourceFilter { public void OnResourceExecuting(ResourceExecutingContext context) { context.HttpContext.Response.WriteAsync($"resource executingr"); } public void OnResourceExecuted(ResourceExecutedContext context) { context.HttpContext.Response.WriteAsync($"resource executed r"); } }
非同步用法：
public class AsyncResourceFilter: IAsyncResourceFilter { public async Task OnResourceExecutionAsync(ResourceExecutingContext context, ResourceExecutionDelegate next) { await context.HttpContext.Response.WriteAsync($" async resource filter in. rn"); await next(); await context.HttpContext.Response.WriteAsync($"async resource filter out. rn"); } }
3）ActionFilter：在調用操作方法之前和之後立即運行程式碼；可以更改傳遞到操作中的參數；可以更改從操作返回的結果。
同步用法：
public class ActionFilter: IActionFilter { public void OnActionExecuting(ActionExecutingContext context) { context.HttpContext.Response.WriteAsync($"action executing r"); } public void OnActionExecuted(ActionExecutedContext context) { context.HttpContext.Response.WriteAsync($"action executed . r"); } }
非同步用法：
public async Task OnActionExecutionAsync(ActionExecutingContext context, ActionExecutionDelegate next) { await context.HttpContext.Response.WriteAsync($"async action execution in. rn"); await next(); await context.HttpContext.Response.WriteAsync($"async action execution out. rn"); }
4）OnException：在向響應正文寫入任何內容之前，對聲明處理的異常應用變數策略。
同步用法：
public class ExceptionFilter: IExceptionFilter { public void OnException(ExceptionContext context) { context.HttpContext.Response.WriteAsync($"exception r"); } }
非同步用法：
public class AsyncExceptionFilter: IAsyncExceptionFilter { public Task OnExceptionAsync(ExceptionContext context) { context.HttpContext.Response.WriteAsync($"exception async r"); return Task.CompletedTask; } }
5）ResultFilter：在執行操作結果之前和之後立即運行程式碼；僅當操作方法成功執行時，其才會運行。 可以設置格式化返回結果：
同步操作：
public class ResultFilter: IResultFilter { public void OnResultExecuting(ResultExecutingContext context) { context.HttpContext.Response.WriteAsync($"result executingr"); } public void OnResultExecuted(ResultExecutedContext context) { context.HttpContext.Response.WriteAsync($"result executed r"); } }
非同步用法：
public class AsyncResultFilter: IAsyncResultFilter { public async Task OnResultExecutionAsync(ResultExecutingContext context, ResultExecutionDelegate next) { await context.HttpContext.Response.WriteAsync($"result execution async in r"); await next(); await context.HttpContext.Response.WriteAsync($"result execution async out. r"); } }
註冊方式我們就是用分區註冊，已經在上面說明，不再多做表述，下面我們看下運行情況（頁面輸出）：
定義一個異常看下結果：
public IActionResult Privacy() { throw new Exception("error"); }
ok，目標達成，不多說了，下次再看攔截器具體實現。
參考文檔：ASP.NET Core 中的篩選器
原創，轉載註明出處。
