.net core 數據統一響應分享

前言

代碼胡亂寫，維護火葬場！

在平時工作中遇到前同事寫介面這樣返回值


當介面返回1時，不去看他的代碼就永遠猜不到這個1代表的是返回成功還是返回值

稍微好點的

維護和改bug簡直讓人瘋狂，導致大部分時間浪費在“體會”別人返回值的邏輯中

天天加班與救bug於水火之中

合理分配前後端返回值很重要！

一般我們常用統一的格式返回json,無論後臺是運行正常還是發生異常，響應給前端的數據格式是不變的！

    public class Result<T> where T : class
    {
        public ResultCode code { get; set; }

        public string msg { get; set; }

        public T data { get; set; }
    }

包裝一下，通常使用構造函數

    public class Result<T> where T : class
    {
        public ResultCode code { get; set; }

        public string msg { get; set; }

        public T data { get; set; }

        public Result(T data)
        {
            code = ResultCode.Ok;
            msg = ResultCode.Ok.GetDescription();
            this.data = data;
        }

        public Result(ResultCode code, string msg, T data)
        {
            this.code = code;
            this.msg = msg ?? code.GetDescription();
            this.data = data;
        }
    }

這麼使用new Result<Store>(code, msg, data)使用起來還是不夠簡化
繼續封裝

    public class Result<T> where T : class
    {
        public ResultCode code { get; set; }

        public string msg { get; set; }

        public T data { get; set; }

        public Result(T data)
        {
            code = ResultCode.Ok;
            msg = ResultCode.Ok.GetDescription();
            this.data = data;
        }

        public Result(ResultCode code, string msg, T data)
        {
            this.code = code;
            this.msg = msg ?? code.GetDescription();
            this.data = data;
        }

        public static Result<T> FromCode(ResultCode code, string msg = null, T data = default)
        {
            if (data == null)
                data = (T) new Object();
            return new Result<T>(code, msg, data);
        }

        public static Result<T> Ok(T data)
        {
            return new Result<T>(data);
        }

        public static Result<T> FromError(ResultCode code = ResultCode.Fail, string msg = null, T data = default)
        {
            return new Result<T>(code, msg, data);
        }
    }

        [HttpGet]
        public Result<Store> Get()
        {
            return Result<Store>.Ok(new Store());
        }

這樣就稍微好點了

全局處理響應數據

雖然控制器返回值可以統一了，但是異常處理並沒有統一，這時候就需要建個中間件/異常過濾器進行處理異常

    app.UseMiddleware<GlobalExceptionHandlerMiddleware>();
    public class GlobalExceptionHandlerMiddleware
    {
        private readonly RequestDelegate _next;

        public GlobalExceptionHandlerMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            try
            {
                await _next(context);
            }
            catch (System.Exception ex)
            {
                context.Response.StatusCode = 500;
                context.Response.ContentType = "text/json;charset=utf-8;";

                if (ex is ResultException == false)
                {
                    var logger = context.RequestServices.GetRequiredService<ILoggerFactory>().CreateLogger<GlobalExceptionHandlerMiddleware>();
                    logger.LogError(1, ex, ex.Message);
                }

                var json = Result<object>.FromCode(ResultCode.Fail, ex.Message);
                var error = JsonSerializer.Serialize(json);

                await context.Response.WriteAsync(error);
            }
        }
    }

有些異常是不需要記錄的，這時候可以自定義ResultException進行判斷

    public class ResultException : Exception
    {
        public ResultException(string message) : base(message)
        {
        }

        public ResultException(string message, Exception e) : base(message, e)
        {

        }
    }

                if (ex is ResultException == false)
                {
                    var logger = context.RequestServices.GetRequiredService<ILoggerFactory>().CreateLogger<GlobalExceptionHandlerMiddleware>();
                    logger.LogError(1, ex, ex.Message);
                }

參數校驗處理

一個介面一般對參數（請求數據）都會進行安全校驗，按照之前的格式返回驗證異常。

    public class ModelActionFilter : ActionFilterAttribute, IActionFilter
    {
        public override void OnActionExecuting(ActionExecutingContext context)
        {
            if (!context.ModelState.IsValid)
            {
                var errorResults = new List<ErrorResultDto>();
                foreach (var item in context.ModelState)
                {
                    var result = new ErrorResultDto
                    {
                        Field = item.Key,
                        Msg = "",
                    };
                    foreach (var error in item.Value.Errors)
                    {
                        if (!string.IsNullOrEmpty(result.Msg))
                        {
                            result.Msg += '|';
                        }
                        result.Msg += error.ErrorMessage;
                    }
                    errorResults.Add(result);
                }
                context.Result = new JsonResult(Result<List<ErrorResultDto>>.FromCode(ResultCode.InvalidData, data: errorResults));
            }
        }
    }

    public class ErrorResultDto
    {
        /// <summary>
        /// 參數領域
        /// </summary>
        public string Field { get; set; }

        /// <summary>
        /// 錯誤信息
        /// </summary>
        public string Msg { get; set; }
    }

Startup.cs

            services.AddControllers(options =>
            {
                options.Filters.Add(new ModelActionFilter());
                options.MaxModelValidationErrors = 50;
                options.ModelBindingMessageProvider.SetValueMustNotBeNullAccessor(
                    _ => "該欄位不可為空。");
            })