从苹果apns的feedback服务器获取推送失败的token

在开发自己的苹果推送服务时候，要合理的控制ios设备的Token,而这个Token是由苹果服务器Apns产生的，就是每次app问Apns要Token，由苹果服务器产生的Token会记录到Apns里面，我们需要根据该Token进行制定设备的消息推送，所有Token需要我们自己去记录和管理，每个设备对应唯一的Token,而app的用户登录会有自己约束的别名，与该tokne进行关系绑定，这样按该别名进行推送，就可以找到对应的Token，进而推送到该iso设备上，对应失效的Token我们需要访问苹果的feedbackServer,拿取失效的Token，然后把本地记录的失效token进行移除。

注意事项：
1.建议和feedback服务器建立长连接，连接过于频繁有可能被当做攻击(简简单单的做一些测试时没有关系的);所有在实际开发完成后，我们基本上可以半天与feedback服务器建立一次socket连接，拿取失效的token,
2.获取的token是在上次你给你的应用发推送失败时加feedback服务的，里面会返回失败的具体时间.
3.返回的数据由三部分组成，请看下面的图：

构中包含三个部分，第一部分是一个上次发推送失败的时间戳，第二个部分是device_token的长度，第三部分就是失效的device_token

贴下PushSharp中连接feedback的代码

     /// <summary>
     /// FeedbackService
     /// </summary>
     public class FeedbackService
     {
         public FeedbackService(ApnsConfiguration configuration)
         {
             Configuration = configuration;
         }

         public ApnsConfiguration Configuration { get; private set; }

         public delegate void FeedbackReceivedDelegate(string deviceToken, DateTime timestamp);
         public event FeedbackReceivedDelegate FeedbackReceived;

         public void Check()
         {
             var encoding = Encoding.ASCII;

             var certificate = Configuration.Certificate;

             var certificates = new X509CertificateCollection();
             certificates.Add(certificate);

             var client = new TcpClient(Configuration.FeedbackHost, Configuration.FeedbackPort);

             var stream = new SslStream(client.GetStream(), true,
                 (sender, cert, chain, sslErrs) => { return true; },
                 (sender, targetHost, localCerts, remoteCert, acceptableIssuers) => { return certificate; });

             stream.AuthenticateAsClient(Configuration.FeedbackHost, certificates, System.Security.Authentication.SslProtocols.Tls, false);

             //Set up
             ];
             ;
             var data = new List<byte>();

             //Get the first feedback
             recd = stream.Read(buffer, , buffer.Length);

             //Continue while we have results and are not disposing
             )
             {
                 // Add the received data to a list buffer to work with (easier to manipulate)
                 ; i < recd; i++)
                     data.Add(buffer[i]);

                 //Process each complete notification "packet" available in the buffer
                  +  + )) // Minimum size for a valid packet
                 {
                     , ).ToArray();
                     , ).ToArray();

                     // Get our seconds since epoch
                     // Check endianness and reverse if needed
                     if (BitConverter.IsLittleEndian)
                         Array.Reverse(secondsBuffer);
                     );

                     //Add seconds since 1970 to that date, in UTC
                     , , , , , , DateTimeKind.Utc).AddSeconds(seconds);

                     //flag to allow feedback times in UTC or local, but default is local
                     if (!Configuration.FeedbackTimeIsUTC)
                         timestamp = timestamp.ToLocalTime();

                     if (BitConverter.IsLittleEndian)
                         Array.Reverse(tokenLengthBuffer);
                     );

                      +  + tokenLength)
                     {

                         , tokenLength).ToArray();
                         // Strings shouldn't care about endian-ness... this shouldn't be reversed
                         //if (BitConverter.IsLittleEndian)
                         //    Array.Reverse (tokenBuffer);
                         var token = BitConverter.ToString(tokenBuffer).Replace("-", "").ToLower().Trim();

                         // Remove what we parsed from the buffer
                         data.RemoveRange(,  +  + tokenLength);

                         // Raise the event to the consumer
                         var evt = FeedbackReceived;
                         if (evt != null)
                             evt(token, timestamp);
                     }
                     else
                     {
                         continue;
                     }

                 }

                 //Read the next feedback
                 recd = stream.Read(buffer, , buffer.Length);
             }

             try
             {
                 stream.Close();
                 stream.Dispose();
             }
             catch { }

             try
             {
                 client.Client.Shutdown(SocketShutdown.Both);
                 client.Client.Dispose();
             }
             catch { }

             try { client.Close(); }
             catch { }
         }
     }

下面是处理逻辑：

     /// <summary>
     /// 处理失效的Token逻辑信息
     /// </summary>
     public class TokenProvider
     {
         private FeedbackService fs = null;
         ;
         private string CID;

         public TokenProvider(ApnsConfiguration cf, string CID)
         {
             this.fs = fs = new FeedbackService(cf);
             this.CID = CID;
             try
             {
                 int hour = int.Parse(ConfigurationManager.AppSettings["ManagerTokenHour"]);//Token的控制时间
             }
             ; }
         }

         /// <summary>
         /// 开启处理失效的Token逻辑信息
         /// </summary>
         /// <param name="cf"></param>
         public void Init()
         {
             try
             {
                 Thread thsub = new Thread(new ThreadStart(() =>
                 {
                     while (true)
                     {
                         try
                         {
                             fs.Check();
                         }
                         catch (Exception ex)
                         {
                             LogInfoProvider.config.Logs.Add(new LogClass() { LogStr = " fs.Check() Error! CID=" + CID, ExInfo = ex });
                         }
                         Thread.Sleep(hour *  *  * );
                     }
                 }));
                 fs.FeedbackReceived += fs_FeedbackReceived;
                 thsub.Start();
                 LogInfoProvider.config.Logs.Add(new LogClass() { LogStr = "Open TokenProvider! CID=" + CID });
             }
             catch (Exception ex)
             { LogInfoProvider.config.Logs.Add(new LogClass() { LogStr = " Open TokenProvider Error! CID=" + CID, ExInfo = ex }); }
         }

         /// <summary>
         /// 处理失效的Token信息
         /// </summary>
         /// <param name="deviceToken"></param>
         /// <param name="timestamp"></param>
         private void fs_FeedbackReceived(string deviceToken, DateTime timestamp)
         {
             try
             {
                 p_DeleteToken p = new p_DeleteToken(deviceToken);
                 if (p.ExecutionDelete()) {
                     LogInfoProvider.config.Logs.Add(new LogClass() { LogStr = "Delete lose token success >> " + deviceToken });
                 } else {
                     LogInfoProvider.config.Logs.Add(new LogClass() { LogStr = "Delete lose token error >> " + deviceToken, ExInfo = null });
                 };
             }
             catch (Exception ex)
             {
                 LogInfoProvider.config.Logs.Add(new LogClass() { LogStr = "fs_FeedbackReceived Error! CID=" + CID, ExInfo = ex });
             }
         }
     }