.net web api在MVC架构下添加过滤器，返回统一类型，异常处理

简介：我们将通过OnActionExecuted方法来实现，OnActionExecuted是ASP.NET Core MVC框架提供的一个过滤器接口方法，用于在控制器方法执行后对结果进行处理。

1. 新建ApiResponseFilter.cs过滤器实现类，继承于IActionFilter类，ApiResponseFilter.cs类全部代码如下

using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.AspNetCore.Mvc;
using MySqlX.XDevAPI.Common;

namespace EF_Core
{
    
    
    public class ApiResponseFilter : IActionFilter
    {
    
    
        public void OnActionExecuted(ActionExecutedContext context)
        {
    
    
            if (context.Exception != null)
            {
    
    
                // 如果发生异常，则返回统一的错误信息
                context.Result = new ObjectResult(new ApiResponse
                {
    
    
                    Success = false,
                    Message = context.Exception.Message,
                    StatusCode = 500
                })
                {
    
    
                    StatusCode = 500
                };
                context.ExceptionHandled = true;
            }
            else if (context.Result is ObjectResult result && result.StatusCode >= 200 && result.StatusCode < 300)
            {
    
    
                // 如果返回结果为ObjectResult且状态码为2xx，则将数据包装成ApiResponse对象
                context.Result = new ObjectResult(new ApiResponse
                {
    
    
                    Success = true,
                    Data = result.Value,
                    StatusCode = result.StatusCode.GetValueOrDefault(200)
                })
                {
    
    
                    StatusCode = result.StatusCode
                };
            }
            else
            {
    
    
                // 如果状态码为null或者不是2xx，将默认状态码设置为200
                context.Result = new ObjectResult(new ApiResponse
                {
    
    
                    Success = true,
                    Data = (context.Result as ObjectResult)?.Value,
                    StatusCode = 200
                })
                {
    
    
                    StatusCode = 200
                };
            }
        }

        public void OnActionExecuting(ActionExecutingContext context)
        {
    
    
            // 在执行Action前的处理，可不实现
        }
    }

    public class ApiResponse
    {
    
    
        public bool Success {
    
     get; set; }
        public string Message {
    
     get; set; }
        public object Data {
    
     get; set; }
        public int StatusCode {
    
     get; set; }
    }
}

2. 在Program.cs类中注册该过滤器。

builder.Services.AddControllers(options =>
 {
    
    
     options.Filters.Add(new ApiResponseFilter()); // 注册ApiResponseFilter
 });

3. 测试返回