WebApi安全性使用TOKEN+签名验证

（2）在请求头中添加timespan（时间戳），nonce（随机数），staffId（用户Id），signature（签名参数）　　　

            //加入头信息
            request.Headers.Add("staffid", staffId.ToString()); //当前请求用户StaffId
            request.Headers.Add("timestamp", timeStamp); //发起请求时的时间戳（单位：毫秒）
            request.Headers.Add("nonce", nonce); //发起请求时的时间戳（单位：毫秒）
            request.Headers.Add("signature", GetSignature(timeStamp,nonce,staffId,data)); //当前请求内容的数字签名

(3)根据请求参数计算本次请求的签名，用timespan+nonc+staffId+token+data（请求参数字符串）得到signStr签名字符串，然后再进行排序和MD5加密得到最终的signature签名字符串，添加到请求头中

private static string GetSignature(string timeStamp,string nonce,int staffId,string data)
        {
            Token token = null;
            var resultMsg = GetSignToken(staffId);
            if (resultMsg != null)
            {
                if (resultMsg.StatusCode == (int)StatusCodeEnum.Success)
                {
                    token = resultMsg.Result;
                }
                else
                {
                    throw new Exception(resultMsg.Data.ToString());
                }
            }
            else
            {
                throw new Exception("token为null，员工编号为：" +staffId);
            }

            var hash = System.Security.Cryptography.MD5.Create();
            //拼接签名数据
            var signStr = timeStamp +nonce+ staffId + token.SignToken.ToString() + data;
            //将字符串中字符按升序排序
            var sortStr = string.Concat(signStr.OrderBy(c => c));
            var bytes = Encoding.UTF8.GetBytes(sortStr);
            //使用MD5加密
            var md5Val = hash.ComputeHash(bytes);
            //把二进制转化为大写的十六进制
            StringBuilder result = new StringBuilder();
            foreach (var c in md5Val)
            {
                result.Append(c.ToString("X2"));
            }
            return result.ToString().ToUpper();
        }

（4） webapi接收到相应的请求，取出请求头中的timespan，nonc，staffid，signature 数据，根据timespan判断此次请求是否失效，根据staffid取出相应token判断token是否失效，根据请求类型取出对应的请求参数，然后服务器端按照同样的规则重新计算请求签名，判断和请求头中的signature数据是否相同，如果相同的话则是合法请求，正常返回数据，如果不相同的话，该请求可能被恶意篡改，禁止访问相应的数据，返回相应的错误信息

如下使用全局过滤器拦截所有api请求进行统一的处理

 public class ApiSecurityFilter : ActionFilterAttribute
    {
        public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext)
        {
            ResultMsg resultMsg = null;
            var request = actionContext.Request;
            string method = request.Method.Method;
            string staffid = String.Empty, timestamp = string.Empty, nonce = string.Empty, signature = string.Empty;
            int id = 0;

            if (request.Headers.Contains("staffid"))
            {
                staffid = HttpUtility.UrlDecode(request.Headers.GetValues("staffid").FirstOrDefault());
            }
            if (request.Headers.Contains("timestamp"))
            {
                timestamp = HttpUtility.UrlDecode(request.Headers.GetValues("timestamp").FirstOrDefault());
            }
            if (request.Headers.Contains("nonce"))
            {
                nonce = HttpUtility.UrlDecode(request.Headers.GetValues("nonce").FirstOrDefault());
            }

            if (request.Headers.Contains("signature"))
            {
                signature = HttpUtility.UrlDecode(request.Headers.GetValues("signature").FirstOrDefault());
            }

            //GetToken方法不需要进行签名验证
            if (actionContext.ActionDescriptor.ActionName == "GetToken")
            {
                if (string.IsNullOrEmpty(staffid) || (!int.TryParse(staffid, out id) || string.IsNullOrEmpty(timestamp) || string.IsNullOrEmpty(nonce)))
                {
                    resultMsg = new ResultMsg();
                    resultMsg.StatusCode = (int)StatusCodeEnum.ParameterError;
                    resultMsg.Info = StatusCodeEnum.ParameterError.GetEnumText();
                    resultMsg.Data = "";
                    actionContext.Response = HttpResponseExtension.toJson(JsonConvert.SerializeObject(resultMsg));
                    base.OnActionExecuting(actionContext);
                    return;
                }
                else
                {
                    base.OnActionExecuting(actionContext);
                    return;
                }
            }


            //判断请求头是否包含以下参数
            if (string.IsNullOrEmpty(staffid) || (!int.TryParse(staffid, out id) || string.IsNullOrEmpty(timestamp) || string.IsNullOrEmpty(nonce) || string.IsNullOrEmpty(signature)))
            {
                resultMsg = new ResultMsg();
                resultMsg.StatusCode = (int)StatusCodeEnum.ParameterError;
                resultMsg.Info = StatusCodeEnum.ParameterError.GetEnumText();
                resultMsg.Data = "";
                actionContext.Response = HttpResponseExtension.toJson(JsonConvert.SerializeObject(resultMsg));
                base.OnActionExecuting(actionContext);
                return;
            }

            //判断timespan是否有效
            double ts1 = 0;
            double ts2 = (DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0)).TotalMilliseconds;
            bool timespanvalidate = double.TryParse(timestamp, out ts1);
            double ts = ts2 - ts1;
            bool falg = ts > int.Parse(WebSettingsConfig.UrlExpireTime) * 1000;
            if (falg || (!timespanvalidate))
            {
                resultMsg = new ResultMsg();
                resultMsg.StatusCode = (int)StatusCodeEnum.URLExpireError;
                resultMsg.Info = StatusCodeEnum.URLExpireError.GetEnumText();
                resultMsg.Data = "";
                actionContext.Response = HttpResponseExtension.toJson(JsonConvert.SerializeObject(resultMsg));
                base.OnActionExecuting(actionContext);
                return;
            }


            //判断token是否有效
            Token token = (Token)HttpRuntime.Cache.Get(id.ToString());
            string signtoken = string.Empty;
            if (HttpRuntime.Cache.Get(id.ToString()) == null)
            {
                resultMsg = new ResultMsg();
                resultMsg.StatusCode = (int)StatusCodeEnum.TokenInvalid;
                resultMsg.Info = StatusCodeEnum.TokenInvalid.GetEnumText();
                resultMsg.Data = "";
                actionContext.Response = HttpResponseExtension.toJson(JsonConvert.SerializeObject(resultMsg));
                base.OnActionExecuting(actionContext);
                return;
            }
            else
            {
                signtoken = token.SignToken.ToString();
            }

            //根据请求类型拼接参数
            NameValueCollection form = HttpContext.Current.Request.QueryString;
            string data = string.Empty;
            switch (method)
            {
                case "POST":
                    Stream stream = HttpContext.Current.Request.InputStream;
                    string responseJson = string.Empty;
                    StreamReader streamReader = new StreamReader(stream);
                    data = streamReader.ReadToEnd();
                    break;
                case "GET":
                    //第一步：取出所有get参数
                    IDictionary<string, string> parameters = new Dictionary<string, string>();
                    for (int f = 0; f < form.Count; f++)
                    {
                        string key = form.Keys[f];
                        parameters.Add(key, form[key]);
                    }

                    // 第二步：把字典按Key的字母顺序排序
                    IDictionary<string, string> sortedParams = new SortedDictionary<string, string>(parameters);
                    IEnumerator<KeyValuePair<string, string>> dem = sortedParams.GetEnumerator();

                    // 第三步：把所有参数名和参数值串在一起
                    StringBuilder query = new StringBuilder();
                    while (dem.MoveNext())
                    {
                        string key = dem.Current.Key;
                        string value = dem.Current.Value;
                        if (!string.IsNullOrEmpty(key))
                        {
                            query.Append(key).Append(value);
                        }
                    }
                    data = query.ToString();
                    break;
                default:
                    resultMsg = new ResultMsg();
                    resultMsg.StatusCode = (int)StatusCodeEnum.HttpMehtodError;
                    resultMsg.Info = StatusCodeEnum.HttpMehtodError.GetEnumText();
                    resultMsg.Data = "";
                    actionContext.Response = HttpResponseExtension.toJson(JsonConvert.SerializeObject(resultMsg));
                    base.OnActionExecuting(actionContext);
                    return;
            }
            
            bool result = SignExtension.Validate(timestamp, nonce, id, signtoken,data, signature);
            if (!result)
            {
                resultMsg = new ResultMsg();
                resultMsg.StatusCode = (int)StatusCodeEnum.HttpRequestError;
                resultMsg.Info = StatusCodeEnum.HttpRequestError.GetEnumText();
                resultMsg.Data = "";
                actionContext.Response = HttpResponseExtension.toJson(JsonConvert.SerializeObject(resultMsg));
                base.OnActionExecuting(actionContext);
                return;
            }
            else
            {
                base.OnActionExecuting(actionContext);
            }
        }
        public override void OnActionExecuted(HttpActionExecutedContext actionExecutedContext)
        {
            base.OnActionExecuted(actionExecutedContext);
        }
    }

然后我们进行测试，检验api请求的合法性

Get请求：

1.获取产品数据，传递参数id=1，name="wahaha" ,完整请求为http://localhost:14826/api/product/getproduct?id=1&name=wahaha

2.请求头添加timespan，staffid，nonce，signature字段

3.如图当data里面的值为id1namewahaha的时候请求头中的signature和服务器端计算出来的result的值是完全一样的，当我将data修改为id1namewahaha1之后，服务器端计算出来的签名result和请求头中提交的signature就不相同了，就表示为不合法的请求了

4.不合法的请求就会被识别为请求参数已被修改

合法的请求则会返回对应的商品信息

post请求：

1.post对象序列化为json字符串后提交到后台，后台返回相应产品信息

2.后台获取请求的参数信息

3.判断签名是否成功，第一次请求签名参数signature和服务器端计算result完全相同，然后当把请求参数中count的数量从10改成100之后服务器端计算的result和请求签名参数signature不同，所以请求不合法，是非法请求，同理如果其他任何参数被修改最后计算的结果都会和签名参数不同，请求同样识别为不合法请求