最近公司有几个项目需要开发手机客户端，服务器端选用WebApi，那么如何保证手机客户端在请求服务器端时数据不被篡改，如何保证一个http请求的失效机制，下面总结一下我们在项目中针对这两个问题的解决方案。
基本思路如下：
用户在成功登陆app客户端之后，手机客户端向服务器端发出的所有的http请求在请求头(HttpHeader)上都会带上下面三个参数：1、Uid(用户ID)，2、Ts（时间戳），3、Sign（签名）。其中Ts是当前时间减去1970-1-1得到的10位的时间时间戳数字，Sign是接口中所有http请求参数与Uid、Ts经过MD5加密后得到的一个字符串。
具体实现如下(客户端的实现，手机客户端生成下面两个参数的思路是一样的)：
1、Ts时间戳
Ts参数可以保证请求的时效性，在手机客户端生成的Ts，在服务器端验证一下，保证请求是在我们规定的时间段内，具体代码如下：
(1)、生成Ts(C#)代码如下，Andriod和IOS可以同理生成
/// <summary> /// 获取十位的时间戳 /// </summary> /// <param name="dt"></param> /// <returns></returns> public string GenerateTimeStamp(DateTime dt) { // Default implementation of UNIX time of the current UTC time TimeSpan ts = dt.ToUniversalTime() - new DateTime(1970, 1, 1, 0, 0, 0, 0); return Convert.ToInt64(ts.TotalSeconds).ToString(); }
(2)、服务器端端验证Ts代码如下，我们规定从手机客户端发到服务器端的请求有效期为5分钟，时间戳参数是跟在Http请求头中
//获取请求头信息 var requestHeader = HttpContext.Current.Request.Headers; //10位时间戳 var Ts = requestHeader.Get("Ts"); //验证Ts是否合法(请求时间有效时间为：加减5分钟) var ts = Ts;//10位时间戳 if (ts.Length != 10) { var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "请求已过期", "application/json"); ; throw new HttpResponseException(resp); } var tsDate = ComHelper.ConvertIntDateTime(ts.ToString()); if (tsDate > DateTime.Now.AddMinutes(5) || tsDate < DateTime.Now.AddMinutes(-5)) { var resp = Request.CreateResponse<string>(HttpStatusCode.OK, "请求已过期", "application/json"); ; throw new HttpResponseException(resp); }
(3)、ComHelper公共类代码如下
using System; using System.Collections.Generic; using System.Collections.Specialized; using System.Linq; using System.Text; using System.Web; using System.Web.Security; namespace OpenAPITest.App_Start { public class ComHelper { /// <summary> /// 获取post/get集合 /// </summary> /// <param name="ignoreCase">true 不区分大小写，统一返回小写 false 区分大小写</param> /// <returns></returns> public static SortedDictionary<string, string> GetRequestSortDic(bool ignoreCase) { int i = 0; SortedDictionary<string, string> sArray = new SortedDictionary<string, string>(); NameValueCollection coll; //Load Form variables into NameValueCollection variable. coll = HttpContext.Current.Request.Form; //coll = HttpContext.Current.Request.Params; // Get names of all forms into a string array. String[] requestItem = coll.AllKeys; for (i = 0; i < requestItem.Length; i++) { if (ignoreCase) sArray.Add(requestItem[i].ToLower(), GetString(requestItem[i])); else sArray.Add(requestItem[i], GetString(requestItem[i])); } coll = HttpContext.Current.Request.QueryString; requestItem = coll.AllKeys; for (i = 0; i < requestItem.Length; i++) { if (ignoreCase) sArray.Add(requestItem[i].ToLower(), GetString(requestItem[i])); else sArray.Add(requestItem[i], GetString(requestItem[i])); } return sArray; } /// <summary> /// 从当前环境中获取 /// </summary> /// <param name="name"></param> /// <param name="defValue"></param> /// <returns></returns> public static string GetString(string name) { string res = ""; var v = HttpContext.Current.Request[name]; if (v != null) { res = v.ToString(); } return res; } /// <summary> /// 时间戳转为C#格式时间 /// </summary> /// <param name="timeStamp"></param> /// <returns></returns> public static DateTime ConvertIntDateTime(string timeStamp) { DateTime dtStart = TimeZone.CurrentTimeZone.ToLocalTime(new DateTime(1970, 1, 1)); long lTime = long.Parse(timeStamp + "0000000"); TimeSpan toNow = new TimeSpan(lTime); return dtStart.Add(toNow); } /// <summary> /// MD5加密 /// </summary> /// <param name="str">原串</param> /// <param name="code">加密位</param> /// <returns></returns> public static string ToMD5(string str) { return FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower(); } /// <summary> /// 获取Sign /// </summary> /// <param name="inputPara"></param> /// <param name="privateKey"></param> /// <returns></returns> public static string GetResponseMysign(SortedDictionary<string, string> inputPara, string privateKey) { string fullstring = GetPostStrings(inputPara, "_sign") + privateKey; return ToMD5(fullstring); } private static string GetPostStrings(SortedDictionary<string, string> inputPara, string excepted) { Dictionary<string, string> sPara = new Dictionary<string, string>(); //过滤空值、sign与sign_type参数 foreach (KeyValuePair<string, string> temp in inputPara) { if (temp.Key.ToLower() != excepted && temp.Value != "" && temp.Value != null) { sPara.Add(temp.Key.ToLower(), temp.Value); } } //获得签名结果 StringBuilder prestr = new StringBuilder(); foreach (KeyValuePair<string, string> temp in sPara) { prestr.Append(temp.Key + "=" + temp.Value + "&"); } //去掉最後一個&字符 int nLen = prestr.Length; if (nLen > 1) prestr.Remove(nLen - 1, 1); return prestr.ToString(); } /// <summary> /// 获取十位的时间戳 /// </summary> /// <param name="dt"></param> /// <returns></returns> public static string GenerateTimeStamp(DateTime dt) { // Default implementation of UNIX time of the current UTC time TimeSpan ts = dt.ToUniversalTime() - new DateTime(1970, 1, 1, 0, 0, 0, 0); return Convert.ToInt64(ts.TotalSeconds).ToString(); } } }