.Net Core--返回拦截统一处理返回值

最近搭项目框架，为了便于接口返回值统一规范，做了一些配置，使得无论接口方法返回值是什么类型，都统一做了拦截，具体实现方式为：

首先需要几个过滤类：异常处理返回类，正常调用统一返回类，忽略返回格式类，

对应类代码如下：

异常处理返回类

 复制代码
using System;
using System.Linq;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.AspNetCore.Mvc.Filters;
namespace S2_Xxxx_XxxNetApi
{
    /// <summary>
    /// Api action统一处理过滤器  
    /// 处理正常返回值
    /// </summary>
    public class ApiResultFilterAttribute : Attribute, IActionFilter
    {
        /// <summary>
        /// 执行方法体之后
        /// 返回结果为JsonResult的请求进行Result包装
        /// </summary>
        /// <param name="context"></param>
        public void OnActionExecuted(ActionExecutedContext context)
        {
            //特殊处理：对有ApiIgnoreAttribute标签的，不进行返回结果包装，原样输出
            var controllerActionDescriptor = context.ActionDescriptor as ControllerActionDescriptor;
            if (controllerActionDescriptor != null)
            {
                var isDefined = controllerActionDescriptor.EndpointMetadata.Any(a => a.GetType().Equals(typeof(ApiIgnoreAttribute)));
                if (isDefined)
                {
                    return;
                }
            }
            // 返回结果为JsonResult的请求进行Result包装
            if (context.Result != null)
            {
                if (context.Result is ObjectResult)
                {
                    var result = context.Result as ObjectResult;
                    context.Result = new JsonResult(new { code = 200, msg = "success", data = result.Value });
                }
                else if (context.Result is EmptyResult)
                {
                    context.Result = new JsonResult(new { code = 200, msg = "success", data = new { } });
                }
                else if (context.Result is ContentResult)
                {
                    var result = context.Result as ContentResult;
                    context.Result = new JsonResult(new { code = result.StatusCode, msg = result.Content });
                }
                else
                {
                    throw new Exception($"未经处理的Result类型：{ context.Result.GetType().Name}");
                }
            }
        }
        /// <summary>
        /// 执行方法体之前
        /// </summary>
        /// <param name="context"></param>
        public void OnActionExecuting(ActionExecutingContext context)
        {
            //不做修改
        }
    }
}

正常调用统一返回类

 复制代码
using System;
using System.Linq;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Controllers;
using Microsoft.AspNetCore.Mvc.Filters;
namespace S2_Xxxx_XxxNetApi
{
    /// <summary>
    /// Api action统一处理过滤器  
    /// 处理正常返回值
    /// </summary>
    public class ApiResultFilterAttribute : Attribute, IActionFilter
    {
        /// <summary>
        /// 执行方法体之后
        /// 返回结果为JsonResult的请求进行Result包装
        /// </summary>
        /// <param name="context"></param>
        public void OnActionExecuted(ActionExecutedContext context)
        {
            //特殊处理：对有ApiIgnoreAttribute标签的，不进行返回结果包装，原样输出
            var controllerActionDescriptor = context.ActionDescriptor as ControllerActionDescriptor;
            if (controllerActionDescriptor != null)
            {
                var isDefined = controllerActionDescriptor.EndpointMetadata.Any(a => a.GetType().Equals(typeof(ApiIgnoreAttribute)));
                if (isDefined)
                {
                    return;
                }
            }
            // 返回结果为JsonResult的请求进行Result包装
            if (context.Result != null)
            {
                if (context.Result is ObjectResult)
                {
                    var result = context.Result as ObjectResult;
                    context.Result = new JsonResult(new { code = 200, msg = "success", data = result.Value });
                }
                else if (context.Result is EmptyResult)
                {
                    context.Result = new JsonResult(new { code = 200, msg = "success", data = new { } });
                }
                else if (context.Result is ContentResult)
                {
                    var result = context.Result as ContentResult;
                    context.Result = new JsonResult(new { code = result.StatusCode, msg = result.Content });
                }
                else
                {
                    throw new Exception($"未经处理的Result类型：{ context.Result.GetType().Name}");
                }
            }
        }
        /// <summary>
        /// 执行方法体之前
        /// </summary>
        /// <param name="context"></param>
        public void OnActionExecuting(ActionExecutingContext context)
        {
            //不做修改
        }
    }
}

忽略返回格式类（这个类根据实际需求调整不需要拦截返回的类型）

 复制代码
using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
namespace S2_Xxxx_XxxNetApi
{
    /// <summary>
    /// 使用该标签，对结果原样输出，不做包装
    /// </summary>
    public class ApiIgnoreAttribute : Attribute
    {
    }
}

然后在程序启动类注入相关方法

 复制代码
public void ConfigureServices(IServiceCollection services)
        {
           //注册过滤器
            services.AddSingleton<ApiResultFilterAttribute>();
            services.AddSingleton<ApiExceptionFilterAttribute>();
            services.AddMvc(
                    config =>
                    {
                        config.EnableEndpointRouting = false;
                        config.Filters.AddService(typeof(ApiResultFilterAttribute));
                        config.Filters.AddService(typeof(ApiExceptionFilterAttribute));
                    })
           .SetCompatibilityVersion(CompatibilityVersion.Version_3_0)
            .AddNewtonsoftJson();
        }

做对应测试就可返回对应的类型

这种返回值就比较统一规范，提高了前后端的协作；