WebApi系列~基于单请求封装多请求的设计

怎么说，单请求封装多请求，这句话确实有点绕了，但还是要看清楚，想明白这到底是怎么一回事，单请求即一次请求（get,post,put,delete），封闭多请求，即在客户端发送的一个请求中可能包含多个子请求（真实的请求，接口），这种设计确实看着很灵活，客户端可以根据自己的需要去拿服务器的数据，确实不错！

首先我们要定义一套自己的请求和响应对象

#region 请求对象
    /// <summary>
    /// 参数对象
    /// </summary>
    [DataContractAttribute]
    public class RequestParam
    {
        public RequestParam(string name, string value)
        {
            this.ParamName = name;
            this.ParamValue = value;
        }
        [DataMemberAttribute]
        public string ParamName { get; private set; }
        [DataMemberAttribute]
        public string ParamValue { get; private set; }
    }
    /// <summary>
    /// 数据包中的实体
    /// </summary>
    [DataContractAttribute]
    public class RequestData
    {
        public RequestData()
        {
            this.HttpMethod = 0;
            this.RequestParam = new Dictionary<string, string>();
        }
        /// <summary>
        /// 本次通讯唯一标示
        /// </summary>
        [DataMemberAttribute]
        public string GuidKey { get; set; }
        /// <summary>
        /// 请求方式0:get,1:Post
        /// </summary>
        public int HttpMethod { get; set; }
        /// <summary>
        /// 要调用的方法
        /// </summary>
        [DataMemberAttribute]
        public string Url { get; set; }
        /// <summary>
        /// 方法的参数列表
        /// </summary>
        [DataMemberAttribute]
        public IDictionary<string, string> RequestParam { get; set; }
    }
    /// <summary>
    /// 请求数据包
    /// </summary>
    [DataContractAttribute]
    public class RequestDataSegment
    {
        public RequestDataSegment()
        {
            this.RequestData = new List<RequestData>();
        }
        [DataMemberAttribute]
        public List<RequestData> RequestData { get; set; }
    }
    #endregion

再来看一下响应对象

#region 响应对象
    /// <summary>
    /// 数据包实体
    /// </summary>
    [DataContractAttribute]
    public class ResponseData
    {
        /// <summary>
        /// 本次传输过程中唯一标识
        /// </summary>
        [DataMemberAttribute]
        public string GuidKey { get; set; }
        /// <summary>
        /// 状态：100失败，200成功
        /// </summary>
        [DataMemberAttribute]
        public int Status { get; set; }
        /// <summary>
        /// 数据包：Json对象
        /// </summary>
        [DataMemberAttribute]
        public string Data { get; set; }
    }
    /// <summary>
    /// 响应数据包
    /// </summary>
    [DataContractAttribute]
    public class ResponseDataSegment
    {
        public ResponseDataSegment()
        {
            this.ResponseData = new List<ResponseData>();
        }
        [DataMemberAttribute]
        public List<ResponseData> ResponseData { get; set; }
    }
    #endregion

而我们服务器对客户端开放的是一个大接口，或者叫入口接口，它负责把客户端传来的请求进行解析，然后代理客户端，处理多请求，并将结果进行组装，返回给客户端，在mvc和web api里，我们为了让程序扩展性更强，通常把这个核心逻辑写在attribute里

下面看一下代码的实现　

    /// <summary>
    /// Api代理过滤器(api多任务请求的入口)
    /// </summary>
    [AttributeUsage(AttributeTargets.Method)]
    public class ApiProxyFilter : ActionFilterAttribute
    {
        public override void OnActionExecuting(ActionExecutingContext filterContext)
        {
            var Request = filterContext.HttpContext.Request;
            var responseDataSegment = new ResponseDataSegment();
            var data = VCommons.SerializeMemoryHelper.DeserializeFromJson<RequestDataSegment>(Request.Form["dataSeg"]);
            if (data != null && data.RequestData.Any())
            {
                foreach (var item in data.RequestData)
                {
                    try
                    {
                        HttpResponseMessage response;
                        var handler = new HttpClientHandler() { AutomaticDecompression = DecompressionMethods.GZip };
                        using (var http = new HttpClient(handler))
                        {

                            if (item.HttpMethod == 0)
                            {
                                if (item.RequestParam != null)
                                {
                                    item.Url += "?";
                                    foreach (var p in item.RequestParam)
                                        item.Url += p.Key + "=" + p.Value + "&";
                                    item.Url = item.Url.Remove(item.Url.Length - 1, 1);
                                }
                                response = http.GetAsync(item.Url).Result;
                            }
                            else
                            {
                                var content = new FormUrlEncodedContent(item.RequestParam);
                                response = http.PostAsync(item.Url, content).Result;
                            }

                            response.EnsureSuccessStatusCode();
                            responseDataSegment.ResponseData.Add(new ResponseData
                            {
                                GuidKey = item.GuidKey,
                                Status = 200,
                                Data = response.Content.ReadAsStringAsync().Result
                            });
                        }
                    }
                    catch (Exception ex)
                    {

                        responseDataSegment.ResponseData.Add(new ResponseData
                        {
                            GuidKey = item.GuidKey,
                            Status = 100,
                            Data = ex.Message
                        });
                    }

                }

            }
            filterContext.HttpContext.Response.ContentType = "applicatin/json";
            filterContext.HttpContext.Response.Write(VCommons.SerializeMemoryHelper.SerializeToJson(responseDataSegment));
            base.OnActionExecuting(filterContext);
        }
    }

对于你的具体项目，选个主入口，在它上面添加上ApiProxy特性即可

　　　　　/// <summary>
        /// Api统一处理的入口
        /// </summary>
        /// <returns></returns>
        [ApiProxyFilter]
        public JsonResult Index()
        {
            return null;
        }

现在你就可以去测试你的客户端了，哈哈，看是否把你的单个请求里的（三个请求）转发并为你返回了，呵呵．