public class ApiTestController : ApiController
{    // GET api/<controller>/5
    public object Get(int id)
    {        return "value" + id;
    }
}

    //
    // 摘要:    //     A base type for handlers which only do some small processing of request and/or    //     response messages.
    public abstract class MessageProcessingHandler : DelegatingHandler
    {        //
        // 摘要:        //     Creates an instance of a System.Net.Http.MessageProcessingHandler class.
        protected MessageProcessingHandler();        //
        // 摘要:        //     Creates an instance of a System.Net.Http.MessageProcessingHandler class with        //     a specific inner handler.        //
        // 参数:        //   innerHandler:        //     The inner handler which is responsible for processing the HTTP response messages.
        protected MessageProcessingHandler(HttpMessageHandler innerHandler);        //
        // 摘要:        //     Performs processing on each request sent to the server.        //
        // 参数:        //   request:        //     The HTTP request message to process.        //
        //   cancellationToken:        //     A cancellation token that can be used by other objects or threads to receive        //     notice of cancellation.        //
        // 返回结果:        //     Returns System.Net.Http.HttpRequestMessage.The HTTP request message that was        //     processed.
        protected abstract HttpRequestMessage ProcessRequest(HttpRequestMessage request, CancellationToken cancellationToken);        //
        // 摘要:        //     Perform processing on each response from the server.        //
        // 参数:        //   response:        //     The HTTP response message to process.        //
        //   cancellationToken:        //     A cancellation token that can be used by other objects or threads to receive        //     notice of cancellation.        //
        // 返回结果:        //     Returns System.Net.Http.HttpResponseMessage.The HTTP response message that was        //     processed.
        protected abstract HttpResponseMessage ProcessResponse(HttpResponseMessage response, CancellationToken cancellationToken);        //
        // 摘要:        //     Sends an HTTP request to the inner handler to send to the server as an asynchronous        //     operation.        //
        // 参数:        //   request:        //     The HTTP request message to send to the server.        //
        //   cancellationToken:        //     A cancellation token that can be used by other objects or threads to receive        //     notice of cancellation.        //
        // 返回结果:        //     Returns System.Threading.Tasks.Task`1.The task object representing the asynchronous        //     operation.        //
        // 异常:        //   T:System.ArgumentNullException:        //     The request was null.
        protected internal sealed override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken);
    }

 1     /// <summary> 2     /// 加密解密接口 3     /// </summary> 4     public interface IMessageEnCryption 5     { 6         /// <summary> 7         /// 加密 8         /// </summary> 9         /// <param name="content"></param>10         /// <returns></returns>11         string Encode(string content);12         /// <summary>13         /// 解密14         /// </summary>15         /// <param name="content"></param>16         /// <returns></returns>17         string Decode(string content);18     }

 1     /// <summary> 2     /// 加解密 只做 base64 3     /// </summary> 4     public class MessageEncryptionVersion1_0 : IMessageEnCryption 5     { 6         public string Decode(string content) 7         { 8             return content?.DecryptBase64(); 9         }10 11         public string Encode(string content)12         {13             return content.EncryptBase64();14         }15     }

 1     public static class EncrypExtends 2     { 3  4         //默认密钥向量 5         private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF }; 6         internal static string Key = "*@&$(@#H"; 7  8         //// <summary> 9         /// DES加密字符串10         /// </summary>11         /// <param name="encryptString">待加密的字符串</param>12         /// <param name="encryptKey">加密密钥,要求为8位</param>13         /// <returns>加密成功返回加密后的字符串，失败返回源串</returns>14         public static string EncryptDES(this string encryptString, string encryptKey)15         {16             try17             {18                 byte[] rgbKey = Encoding.UTF8.GetBytes(encryptKey.Substring(0, 8));19                 byte[] rgbIV = Keys;20                 byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);21                 DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();22                 MemoryStream mStream = new MemoryStream();23                 CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);24                 cStream.Write(inputByteArray, 0, inputByteArray.Length);25                 cStream.FlushFinalBlock();26                 return Convert.ToBase64String(mStream.ToArray());27             }28             catch29             {30                 return encryptString;31             }32         }33         //// <summary>34         /// DES解密字符串35         /// </summary>36         /// <param name="decryptString">待解密的字符串</param>37         /// <param name="decryptKey">解密密钥,要求为8位,和加密密钥相同</param>38         /// <returns>解密成功返回解密后的字符串，失败返源串</returns>39         public static string DecryptDES(this string decryptString, string key)40         {41             try42             {43                 byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));44                 byte[] rgbIV = Keys;45                 byte[] inputByteArray = Convert.FromBase64String(decryptString);46                 DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();47                 MemoryStream mStream = new MemoryStream();48                 CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);49                 cStream.Write(inputByteArray, 0, inputByteArray.Length);50                 cStream.FlushFinalBlock();51                 return Encoding.UTF8.GetString(mStream.ToArray());52             }53             catch54             {55                 return decryptString;56             }57         }58         public static string EncryptBase64(this string encryptString)59         {60             return Convert.ToBase64String(Encoding.UTF8.GetBytes(encryptString));61         }62         public static string DecryptBase64(this string encryptString)63         {64             return Encoding.UTF8.GetString(Convert.FromBase64String(encryptString));65         }66         public static string DecodeUrl(this string cryptString)67         {68             return System.Web.HttpUtility.UrlDecode(cryptString);69         }70         public static string EncodeUrl(this string cryptString)71         {72             return System.Web.HttpUtility.UrlEncode(cryptString);73         }74     }

 1     /// <summary> 2     ///  API消息请求处理 3     /// </summary> 4     public class JoyMessageHandler : MessageProcessingHandler 5     { 6  7         /// <summary> 8         /// 接收到request时 处理 9         /// </summary>10         /// <param name="request"></param>11         /// <param name="cancellationToken"></param>12         /// <returns></returns>13         protected override HttpRequestMessage ProcessRequest(HttpRequestMessage request, CancellationToken cancellationToken)14         {15             if (request.Content.IsMimeMultipartContent())16                 return request;17             // 获取请求头中 api_version版本号18             var ver = System.Web.HttpContext.Current.Request.Headers.GetValues("api_version")?.FirstOrDefault();19             // 根据api_version版本号获取加密对象, 如果为null 则不需要加密20             var encrypt = MessageEncryptionCreator.GetInstance(ver);21 22             if (encrypt != null)23             {24                 // 读取请求body中的数据25                 string baseContent = request.Content.ReadAsStringAsync().Result;26                 // 获取加密的信息27                 // 兼容 body: 加密数据  和 body: code=加密数据28                 baseContent = baseContent.Match("(code=)*(?<code>[\\S]+)", 2);29                 // URL解码数据30                 baseContent = baseContent.DecodeUrl();31                 // 用加密对象解密数据32                 baseContent = encrypt.Decode(baseContent);33 34                 string baseQuery = string.Empty;35                 if (!request.RequestUri.Query.IsNullOrEmpty())36                 {37                     // 同 body38                     // 读取请求 url query数据39                     baseQuery = request.RequestUri.Query.Substring(1);40                     baseQuery = baseQuery.Match("(code=)*(?<code>[\\S]+)", 2);41                     baseQuery = baseQuery.DecodeUrl();42                     baseQuery = encrypt.Decode(baseQuery);43                 }44                 // 将解密后的 URL 重置URL请求45                 request.RequestUri = new Uri($"{request.RequestUri.AbsoluteUri.Split('?')[0]}?{baseQuery}");46                 // 将解密后的BODY数据 重置47                 request.Content = new StringContent(baseContent);48             }49 50             return request;51         }52 53         /// <summary>54         /// 处理将要向客户端response时55         /// </summary>56         /// <param name="response"></param>57         /// <param name="cancellationToken"></param>58         /// <returns></returns>59         protected override HttpResponseMessage ProcessResponse(HttpResponseMessage response, CancellationToken cancellationToken)60         {61             //var isMediaType = response.Content.Headers.ContentType.MediaType.Equals(mediaTypeName, StringComparison.OrdinalIgnoreCase);62             var ver = System.Web.HttpContext.Current.Request.Headers.GetValues("api_version")?.FirstOrDefault();63             var encrypt = MessageEncryptionCreator.GetInstance(ver);64             if (encrypt != null)65             {66                 if (response.StatusCode == HttpStatusCode.OK)67                 {68                     var result = response.Content.ReadAsStringAsync().Result;69                     // 返回消息 进行加密70                     var encodeResult = encrypt.Encode(result);71                     response.Content = new StringContent(encodeResult);72                 }73             }74 75             return response;76         }77 78     }

 1     public static class WebApiConfig 2     { 3         public static void Register(HttpConfiguration config) 4         { 5             // Web API 配置和服务 6             // 将 Web API 配置为仅使用不记名令牌身份验证。 7             config.SuppressDefaultHostAuthentication(); 8             config.Filters.Add(new HostAuthenticationFilter(OAuthDefaults.AuthenticationType)); 9 10             // Web API 路由11             config.MapHttpAttributeRoutes();12 13             config.Routes.MapHttpRoute(14                 name: "DefaultApi",15                 routeTemplate: "api/{controller}/{id}",16                 defaults: new { id = RouteParameter.Optional }17             );18 19             // 添加自定义消息处理20             config.MessageHandlers.Add(new JoyMessageHandler());21 22         }23     }

 1  [TestMethod()] 2         public void GetTest() 3         { 4             var id = 10; 5             var resultSuccess = $"\"value{id}\""; 6             //不加密 7             Trace.WriteLine($"without encryption."); 8             var url = $"api/ApiTest?id={id}"; 9             Trace.WriteLine($"get url : {url}");10             var response = http.GetAsync(url).Result;11             var result = response.Content.ReadAsStringAsync().Result;12             Assert.AreEqual(result, resultSuccess);13             Trace.WriteLine($"result : {result}");14 15             //使用 方案1加密16             Trace.WriteLine($"encryption case one.");17 18             url = $"api/ApiTest?code=" + $"id={id}".EncryptBase64().EncodeUrl();19 20             Trace.WriteLine($"get url : {url}");21 22             http.DefaultRequestHeaders.Clear();23             http.DefaultRequestHeaders.Add("api_version", "1.0");24             response = http.GetAsync(url).Result;25 26             result = response.Content.ReadAsStringAsync().Result;27 28             Trace.WriteLine($"result : {result}");29 30             result = result.DecryptBase64();31 32             Trace.WriteLine($"DecryptBase64 : {result}");33 34             Assert.AreEqual(result, resultSuccess);35 36             //使用 方案2 加密通讯37             Trace.WriteLine($"encryption case one.");38             39             url = $"api/ApiTest?code=" + $"id={id}".EncryptDES(MessageEncryptionVersion1_1.KEY).EncodeUrl();40 41             Trace.WriteLine($"get url : {url}");42 43             http.DefaultRequestHeaders.Clear();44             http.DefaultRequestHeaders.Add("api_version", "1.1");45             response = http.GetAsync(url).Result;46 47             result = response.Content.ReadAsStringAsync().Result;48 49             Trace.WriteLine($"result : {result}");50 51             result = result.DecryptDES(MessageEncryptionVersion1_1.KEY);52 53             Trace.WriteLine($"DecryptBase64 : {result}");54 55             Assert.AreEqual(result, resultSuccess);56         }