WebApi(二)-重新封装返回结果

如果不想写代码直接使用nuget安装笔者已经封装好的就可以马上实现(nuget搜索ZetaWebApi)选择>=1.0.1版本-----不懂使用nuget的请查看笔者的nuget系列文章

如果习惯自己写代码请继续往下看

先创建要返回的结果类型:

/// <summary>
    /// 返回类型
    /// </summary>
    public class ApiResultModel
    {
        private HttpStatusCode statusCode;

        private object data;

        private string errorMessage;

        private bool isSuccess;

        /// <summary>
        /// 状态代码
        /// </summary>
        public HttpStatusCode StatusCode
        {
            get { return statusCode; }
            set { statusCode = value; }
        }

        /// <summary>
        /// 返回的数据
        /// </summary>
        public object Data
        {
            get { return data; }
            set { data = value; }
        }

        /// <summary>
        /// 错误消息
        /// </summary>
        public string ErrorMessage
        {
            get { return errorMessage; }
            set { errorMessage = value; }
        }

        /// <summary>
        /// 是否成功
        /// </summary>
        public bool IsSuccess
        {
            get { return isSuccess; }
            set { isSuccess = value; }
        }
    }

然后创建重写ActionFilterAttribute下的OnActionExecuted(执行action之后):

先建一个类名字随意如:ApiResultAttribute继承于System.Web.Http.Filters.ActionFilterAttribute详细代码如下:

以下代码需注意要引用using System.Net.Http否则ReadAsAsync不能使用

 public class ApiResultAttribute : System.Web.Http.Filters.ActionFilterAttribute
    {
        public  override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
        {

            base.OnActionExecuted(actionExecutedContext);

            ApiResultModel result = new ApiResultModel();


            // 取得由 API 返回的状态代码
            result.StatusCode = actionExecutedContext.ActionContext.Response.StatusCode;

            // 取得由 API 返回的资料
            result.Data = actionExecutedContext.ActionContext.Response.Content.ReadAsAsync<object>().Result;

            //请求是否成功
            result.IsSuccess = actionExecutedContext.ActionContext.Response.IsSuccessStatusCode;

            //结果转为自定义消息格式
            HttpResponseMessage httpResponseMessage = JsonHelper.toJson(result);

            // 重新封装回传格式
            actionExecutedContext.Response = httpResponseMessage;

            
        }
    }

上面的JsonHelper.toJson()是事先写好的代码如下:创建类JsonHelper

public static HttpResponseMessage toJson(Object obj)
        {
            String str;
            if (obj is String || obj is Char)//如果是字符串或字符直接返回
            {
                str = obj.ToString();
            }
            else//否则序列为json字串
            {
                JavaScriptSerializer serializer = new JavaScriptSerializer();
                str = serializer.Serialize(obj);
            }
            HttpResponseMessage result = new HttpResponseMessage { Content = new StringContent(str, Encoding.GetEncoding("UTF-8"), "application/json") };
            return result;
        }

建完之后在WebApiConfig下注册:

config.Filters.Add(new ApiResultAttribute());//重新包装结果

完成以上步骤即可使用。

补充:

特殊情况不需要封装返回结果,解决方法:

1创建一个自定义属性

假设自定义类名为NoPackageResult继承Attribute

public class NoPackageResult : Attribute
    {
       
    }

2,修改上面的ApiResultAttribute类里的OnActionExecuted方法

在方法里加一个判断是否有属性有的情况下就不做封装的步骤

var noPackage = actionExecutedContext.ActionContext.ActionDescriptor.GetCustomAttributes<NoPackageResult>();
            if (!noPackage.Any())
            {
                 //执行封装
            }         

3在不需要封装的接口上添加属性NoPackageResult如下:

ApiResultAttribute类完整代码:

public class ApiResultAttribute : System.Web.Http.Filters.ActionFilterAttribute
    {
        public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
        {
            base.OnActionExecuted(actionExecutedContext);
            
            // 不包裹返回值
            var noPackage = actionExecutedContext.ActionContext.ActionDescriptor.GetCustomAttributes<NoPackageResult>();
            if (!noPackage.Any())
            {
                //初始化返回结果
                ApiResultModel result = new ApiResultModel();
                if (actionExecutedContext.Exception != null)
                {
                    result.Code = "sys_error";
                    result.Success = false;
                    result.Message = actionExecutedContext.Exception.Message;
                }
                else
                {
                    // 取得由 API 返回的状态代码
                    result.Code = actionExecutedContext.ActionContext.Response.StatusCode.ToString();

                    var a = actionExecutedContext.ActionContext.Response.Content.ReadAsAsync<object>();
                    if (!a.IsFaulted)
                    {
                        // 取得由 API 返回的资料
                        result.Data = actionExecutedContext.ActionContext.Response.Content.ReadAsAsync<object>().Result;
                    }

                    //请求是否成功
                    result.Success = actionExecutedContext.ActionContext.Response.IsSuccessStatusCode;
                }
                

                //结果转为自定义消息格式
                HttpResponseMessage httpResponseMessage = CustomerHttpResponseMessage.toJson(result);

                // 重新封装回传格式
                actionExecutedContext.Response = httpResponseMessage;
            }

        }
    }