WEB API 系列（二） Filter的使用以及执行顺序

    public class AuthFilterAttribute : AuthorizationFilterAttribute
    { public override void OnAuthorization(HttpActionContext actionContext)
        { //如果用户方位的Action带有AllowAnonymousAttribute，则不进行授权验证 if (actionContext.ActionDescriptor.GetCustomAttributes().Any())
            { return;
            } var verifyResult = actionContext.Request.Headers.Authorization!=null && //要求请求中需要带有Authorization头 actionContext.Request.Headers.Authorization.Parameter == "123456"; //并且Authorization参数为123456则验证通过 if (!verifyResult)
            { //如果验证不通过，则返回401错误，并且Body中写入错误原因 actionContext.Response = actionContext.Request.CreateErrorResponse(HttpStatusCode.Unauthorized,new HttpError("Token 不正确"));
            }
        }
    }

    public class PersonController : ApiController
    {
        [AuthFilter] public CreateResult Post(CreateUser user)
        { return new CreateResult() {Id = "123"};
        }
    }

 [AuthFilter] public class PersonController : ApiController
    { public CreateResult Post(CreateUser user)
        { return new CreateResult() {Id = "123"};
        }
    }

public static void Register(HttpConfiguration config)
{  config.MapHttpAttributeRoutes();
　　  //注册全局Filter
     config.Filters.Add(new AuthFilterAttribute());

     config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
}

[AllowAnonymous] public CreateResult PostLogin(LoginEntity entity)
{ //TODO:添加验证逻辑 return new CreateResult() {Id = "123456"};
}

 public class CustomActionFilterAttribute : ActionFilterAttribute
{ public override void OnActionExecuting(HttpActionContext actionContext)
    { if (!actionContext.ModelState.IsValid)
        {
            actionContext.Response = actionContext.Request.CreateErrorResponse(HttpStatusCode.BadRequest,  actionContext.ModelState);
        }
    }
}

public class LoginEntity
{
    [Required(ErrorMessage = "缺少用户名")] public string UserName { get; set; }

    [Required(ErrorMessage = "缺少密码")] public string Password { get; set; }
}

[AllowAnonymous]
[CustomActionFilter] public CreateResult PostLogin(LoginEntity entity)
{ //TODO:添加验证逻辑 return new CreateResult() {Id = "123456"};
}

public override async Task OnActionExecutedAsync(HttpActionExecutedContext actionExecutedContext, CancellationToken cancellationToken)
{ var key = 10; var responseBody = await actionExecutedContext.Response.Content.ReadAsByteArrayAsync(); //以Byte数组方式读取Content中的数据 for (int i = 0; i )
        {
            responseBody[i] = (byte)(responseBody[i] ^ key); //对每一个Byte做异或运算  }

        actionExecutedContext.Response.Content = new ByteArrayContent(responseBody); //将结果赋值给Response的Content  actionExecutedContext.Response.Content.Headers.ContentType = MediaTypeHeaderValue.Parse("Encrypt/Bytes"); //并修改Content-Type }

public class ExceptionFilter : ExceptionFilterAttribute
{ public override void OnException(HttpActionExecutedContext actionExecutedContext)
    { //如果截获异常为我们自定义，可以处理的异常则通过我们自己的规则处理 if (actionExecutedContext.Exception is DemoException)
        { //TODO:记录日志 actionExecutedContext.Response = actionExecutedContext.Request.CreateResponse(
                    HttpStatusCode.BadRequest, new {Message = actionExecutedContext.Exception.Message});
        } else { //如果截获异常是我没无法预料的异常，则将通用的返回信息返回给用户，避免泄露过多信息，也便于用户处理 //TODO:记录日志 actionExecutedContext.Response = actionExecutedContext.Request.CreateResponse(HttpStatusCode.InternalServerError, new {Message = "服务器被外星人拐跑了！"});
        }
    }
}

 [CustomerExceptionFilter] public class TestController : ApiController
{ public int Get(int a, int b)
    { if (a  b)
        { throw new DemoException("A必须要比B大！");
        } if (a == b)
        { throw new NotImplementedException();
        } return a*b;
    }
}