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．