ASP.NET CORE學(xué)習(xí)教程之自定義異常處理詳解

/// <summary>
 /// 異常中間件配置對象
 /// </summary>
 public class CustomExceptionMiddleWareOption
 {
 public CustomExceptionMiddleWareOption(
 CustomExceptionHandleType handleType = CustomExceptionHandleType.JsonHandle,
 IList<PathString> jsonHandleUrlKeys = null,
 string errorHandingPath = "")
 {
 HandleType = handleType;
 JsonHandleUrlKeys = jsonHandleUrlKeys;
 ErrorHandingPath = errorHandingPath;
 }

 /// <summary>
 /// 異常處理方式
 /// </summary>
 public CustomExceptionHandleType HandleType { get; set; }

 /// <summary>
 /// Json處理方式的Url關(guān)鍵字
 /// <para>僅HandleType=Both時(shí)生效</para>
 /// </summary>
 public IList<PathString> JsonHandleUrlKeys { get; set; }

 /// <summary>
 /// 錯(cuò)誤跳轉(zhuǎn)頁面
 /// </summary>
 public PathString ErrorHandingPath { get; set; }
 }

 /// <summary>
 /// 錯(cuò)誤處理方式
 /// </summary>
 public enum CustomExceptionHandleType
 {
 JsonHandle = 0, //Json形式處理
 PageHandle = 1, //跳轉(zhuǎn)網(wǎng)頁處理
 Both = 2 //根據(jù)Url關(guān)鍵字自動(dòng)處理
 }

/// <summary>
 /// 管道請求委托
 /// </summary>
 private RequestDelegate _next;

 /// <summary>
 /// 配置對象
 /// </summary>
 private CustomExceptionMiddleWareOption _option;

 /// <summary>
 /// 需要處理的狀態(tài)碼字典
 /// </summary>
 private IDictionary<int, string> exceptionStatusCodeDic;

 public CustomExceptionMiddleWare(RequestDelegate next, CustomExceptionMiddleWareOption option)
 {
 _next = next;
 _option = option;
 exceptionStatusCodeDic = new Dictionary<int, string>
 {
 { 401, "未授權(quán)的請求" },
 { 404, "找不到該頁面" },
 { 403, "訪問被拒絕" },
 { 500, "服務(wù)器發(fā)生意外的錯(cuò)誤" }
 //其余狀態(tài)自行擴(kuò)展
 };
 }

public async Task Invoke(HttpContext context)
 {
 Exception exception = null;
 try
 {
 await _next(context); //調(diào)用管道執(zhí)行下一個(gè)中間件
 }
 catch (Exception ex)
 {
 context.Response.Clear(); 
 context.Response.StatusCode = 500; //發(fā)生未捕獲的異常，手動(dòng)設(shè)置狀態(tài)碼
 exception = ex;
 }
 finally
 {
 if (exceptionStatusCodeDic.ContainsKey(context.Response.StatusCode) && 
 !context.Items.ContainsKey("ExceptionHandled")) //預(yù)處理標(biāo)記
 {
 var errorMsg = string.Empty;
 if (context.Response.StatusCode == 500 && exception != null)
 {
 errorMsg = $"{exceptionStatusCodeDic[context.Response.StatusCode]}\r\n{(exception.InnerException != null ? exception.InnerException.Message : exception.Message)}";
 }
 else
 {
 errorMsg = exceptionStatusCodeDic[context.Response.StatusCode];
 }
 exception = new Exception(errorMsg);
 }

 if (exception != null)
 {
 var handleType = _option.HandleType;
 if (handleType == CustomExceptionHandleType.Both) //根據(jù)Url關(guān)鍵字決定異常處理方式
 {
 var requestPath = context.Request.Path;
 handleType = _option.JsonHandleUrlKeys != null && _option.JsonHandleUrlKeys.Count(
 k => context.Request.Path.StartsWithSegments(k, StringComparison.CurrentCultureIgnoreCase)) > 0 ?
 CustomExceptionHandleType.JsonHandle :
 CustomExceptionHandleType.PageHandle;
 }
 
 if (handleType == CustomExceptionHandleType.JsonHandle)
 await JsonHandle(context, exception);
 else
 await PageHandle(context, exception, _option.ErrorHandingPath);
 }
 }
 }

 /// <summary>
 /// 統(tǒng)一格式響應(yīng)類
 /// </summary>
 /// <param name="ex"></param>
 /// <returns></returns>
 private ApiResponse GetApiResponse(Exception ex)
 {
 return new ApiResponse() { IsSuccess = false, Message = ex.Message };
 }

 /// <summary>
 /// 處理方式：返回Json格式
 /// </summary>
 /// <param name="context"></param>
 /// <param name="ex"></param>
 /// <returns></returns>
 private async Task JsonHandle(HttpContext context, Exception ex)
 {
 var apiResponse = GetApiResponse(ex);
 var serialzeStr = JsonConvert.SerializeObject(apiResponse);
 context.Response.ContentType = "application/json";
 await context.Response.WriteAsync(serialzeStr, Encoding.UTF8);
 }

 /// <summary>
 /// 處理方式：跳轉(zhuǎn)網(wǎng)頁
 /// </summary>
 /// <param name="context"></param>
 /// <param name="ex"></param>
 /// <param name="path"></param>
 /// <returns></returns>
 private async Task PageHandle(HttpContext context, Exception ex, PathString path)
 {
 context.Items.Add("Exception", ex);
 var originPath = context.Request.Path;
 context.Request.Path = path; //設(shè)置請求頁面為錯(cuò)誤跳轉(zhuǎn)頁面
 try
 {
 await _next(context); 
 }
 catch { }
 finally
 {
 context.Request.Path = originPath; //恢復(fù)原始請求頁面
 }
 }

public static class CustomExceptionMiddleWareExtensions
 {

 public static IApplicationBuilder UseCustomException(this IApplicationBuilder app, CustomExceptionMiddleWareOption option)
 {
 return app.UseMiddleware<CustomExceptionMiddleWare>(option);
 }
 }

 app.UseCustomException(new CustomExceptionMiddleWareOption(
 handleType: CustomExceptionHandleType.Both, //根據(jù)url關(guān)鍵字決定處理方式
 jsonHandleUrlKeys: new PathString[] { "/api" },
 errorHandingPath: "/home/error"));