webapi的幾種過濾器

好久沒有寫博客了 今天就來聊聊asp.net webapi的過濾器們

過濾器主要有這么幾種

AuthorizationFilterAttribute 權限驗證

ActionFilterAttribute 日志 參數驗證等

ExceptionFilterAttribute 異常處理捕獲

我是如何使用這些過濾器的，最近在做項目中，這幾種過濾器我都使用了，實現當別人調用接口的時候，首先驗證權限，這個驗證信息可以從Head里取也可以從Body里取，然后就是驗證參數的有效性，參數需要后台驗證，在實體里我都是定義了驗證特性，攔截器正好根據這些特性統一做后台驗證，所以我的后台數據驗證統一在這一步就做完了，如果不符合直接拋出給客戶端，然后還可以寫日志，最后是異常的捕獲，異常攔截器統一捕獲異常，我在其它層就不要額外的做異常處理（事務方法除外，事務需要捕獲異常回滾）

這些過濾器 作為全局過濾器直接配置好 不用每個api controller都去聲明特性

    /// <summary>
    /// 接口的權限驗證
    /// Token身份驗證，只有合法的用戶才可以訪問  否則會轉向到登錄頁面或者無權限提示頁面
    /// </summary>
    public class AuthGlobalAttribute : AuthorizationFilterAttribute
    {
        public string Roles { get; set; }

        public string Users { get; set; }

        public override void OnAuthorization(HttpActionContext actionContext)
        {
            if (actionContext.ActionDescriptor.GetCustomAttributes<AllowAnonymousAttribute>().Any())
            {
                return;
            }
            string controllerName = actionContext.ActionDescriptor.ControllerDescriptor.ControllerName;
            string actionName = actionContext.ActionDescriptor.ActionName;
            HttpContextBase context = (HttpContextBase)actionContext.Request.Properties["MS_HttpContext"];//獲取傳統context
            HttpRequestBase request = context.Request;//定義傳統request對象 
            if (request["Token"] == null && actionContext.Request.Headers.Authorization == null)
            {
                Result result = new Result { Flag = false, Message = "缺少Token身份信息", Code="203" };
                HttpResponseMessage httpResponseMessage = new HttpResponseMessage();
                httpResponseMessage.Content = new StringContent(JsonConvert.SerializeObject(result), Encoding.UTF8, "application/json");
                httpResponseMessage.StatusCode = HttpStatusCode.BadRequest;
                actionContext.Response = httpResponseMessage;
                return;
            }
            //參數帶有Token
            string token = request["Token"];
            token = (token ?? actionContext.Request.Headers.Authorization.Parameter);

            //根據Token獲取當前用戶上下文
            if (UserCache.Cache.Get(token) != null)
            {
                HttpContext.Current.Items["User"] = UserCache.Cache.Get(token);
                //獲取用戶上下文后 根據Roles屬性比對過濾器角色 如果沒有權限向外面拋401
            }
            else
            {
                Result result = UserBLL.GetUserByToken(token);
                HttpResponseMessage httpResponseMessage = new HttpResponseMessage();
                httpResponseMessage.Content = new StringContent(JsonConvert.SerializeObject(result), Encoding.UTF8, "application/json");
                httpResponseMessage.StatusCode = HttpStatusCode.BadRequest;
                actionContext.Response = httpResponseMessage;
                //actionContext.Response = actionContext.Request.CreateErrorResponse(HttpStatusCode.Unauthorized, new HttpError("您無權限訪問"));
                return;
            }
            base.OnAuthorization(actionContext);
        }


    }

 

    /// <summary>
    /// 全局參數驗證實體
    /// </summary>
    public class ValidateGlobalAttribute : ActionFilterAttribute
    {
        /// <summary>
        /// 所有實體參數接口 全局驗證
        /// </summary>
        /// <param name="filterContext"></param>
        public override void OnActionExecuting(HttpActionContext filterContext)
        {
            if (!filterContext.ModelState.IsValid)
            {
                ValidateResults vresult = new ValidateResults();
                foreach (string key in filterContext.ModelState.Keys)
                {
                    if (filterContext.ModelState[key].Errors.Count > 0)
                    {
                        vresult.ErrorResults.Add(new ValidateResult
                        {
                            IsValid = false,
                            MemberName = key,
                            ErrorMessage = filterContext.ModelState[key].Errors[0].ErrorMessage
                        });
                    }
                }
                Result<ValidateResults> result = new Result<ValidateResults> { Flag = false, Message = "數據驗證失敗", ResultObj = vresult,Code="208" };
                HttpResponseMessage httpResponseMessage = new HttpResponseMessage();
                httpResponseMessage.Content = new StringContent(JsonConvert.SerializeObject(result), Encoding.UTF8, "application/json");
                httpResponseMessage.StatusCode = HttpStatusCode.BadRequest;
                filterContext.Response = httpResponseMessage;
                return;
               // throw new HttpResponseException(oHttpResponseMessage);
            }
            base.OnActionExecuting(filterContext);
        }

    }

 

    /// <summary>
    /// 異常全局處理
    /// </summary>
    public class ExceptionGlobalAtrribute : ExceptionFilterAttribute
    {
        public override void OnException(HttpActionExecutedContext filterContext)
        {
            if (filterContext.Exception != null)
            {
                string controllerName = filterContext.ActionContext.ActionDescriptor.ControllerDescriptor.ControllerName;
                string actionName = filterContext.ActionContext.ActionDescriptor.ActionName;
                HttpContextBase context = (HttpContextBase)filterContext.Request.Properties["MS_HttpContext"];//獲取傳統context
                HttpRequestBase request = context.Request;//定義傳統request對象 
                string token = string.Empty;
                if (request["Token"] != null || filterContext.Request.Headers.Authorization != null)
                {
                    token = request["Token"];
                    token = (token ?? filterContext.Request.Headers.Authorization.Parameter);
                }
                //獲取當前用戶上下文
                UserContext user = UserCache.Cache.Get(token);
                string description = filterContext.Exception.Message.ToString();
                //int autokey = DaoPack.Sys_UserLogDao.GetMax<int>(m => m.AutoKey) + 1;

                Sys_UserLog log = new Sys_UserLog
                {
                    //AutoKey = autokey,
                    ActionName = controllerName + "/" + actionName,
                    Description = description,
                    UserID = user == null ? null : (int?)user.UserID,
                    UserName = user == null ? null : user.UserName,
                    Url = request.RawUrl,
                    ClientIP=SysService.GetHostAddress()
                };
                DaoPack.Sys_UserLogDao.Insert(log);
            }
            HttpResponseMessage httpResponseMessage = new HttpResponseMessage();
            Result result = new Result { Flag = false, Message = "接口異常",Code="400" };
            httpResponseMessage.Content = new StringContent(JsonConvert.SerializeObject(result), Encoding.UTF8, "application/json");
            httpResponseMessage.StatusCode = HttpStatusCode.BadRequest;
            filterContext.Response = httpResponseMessage;
            return;
            //throw new HttpResponseException(oHttpResponseMessage);
            // base.OnException(filterContext);

        }
    }