Subscriptions in UCMA part 4: Presence (PIDF)

In this part I'll show you how to implement subscriptions using PIDF. See also Subscriptions in UCMA part 3: Presence.

First we need as with all subscriptions the ISipSubscriptionProcessor.

public class PresenceSubscriptionPIDF : ISipSubscriptionProcessor
    {

        #region ISipSubscriptionProcessor Members

        void ISipSubscriptionProcessor.GetExtensionHeaders(SipSubscription.RequestType requestType, out IEnumerable<SignalingHeader> extensionHeaders)
        {
           
            extensionHeaders = null;
        }

        void ISipSubscriptionProcessor.GetMessageBody(SipSubscription.RequestType requestType, out ContentType contentType, out byte[] messageBody)
        {
            contentType = null;
            messageBody = new Byte[0];

        }

        void ISipSubscriptionProcessor.ProcessErrorResponse(SipResponseData message)
        {
            Console.WriteLine("error = " + message.ResponseCode);
        }

        public void ProcessNotification(SipMessageData message)
        {
            string s = message.GetMessageBodyString();
            string status = "online";
            string sip = "";
            try{
                XmlDocument doc = new XmlDocument();
                doc.LoadXml(s);
                XmlNamespaceManager nsmanager = new XmlNamespaceManager(doc.NameTable);
                nsmanager.AddNamespace("p", "urn:ietf:params:xml:ns:pidf");
                nsmanager.AddNamespace("ep", "urn:ietf:params:xml:ns:pidf:status:rpid-status");
                nsmanager.AddNamespace("ci", "urn:ietf:params:xml:ns:pidf:cipid");
                XmlNode node = null;
                node = doc.SelectSingleNode("//p:presence", nsmanager);
                sip = node.Attributes["entity"].Value;
                node = doc.SelectSingleNode("//p:presence/p:tuple/p:status/p:basic", nsmanager);
                if (node.InnerText == "closed")
                {
                    status = "offline";
                }
                else{
                    node = doc.SelectSingleNode("//ep:activities/ep:activity", nsmanager);
                    status = node.InnerText;
                }
                   
                
            }catch{
            }
           //TODO 
        }

        void ISipSubscriptionProcessor.SubscriptionStateChanged(SubscriptionStateChangedEventArgs eventArg)
        {
           //TODO
        }
      
        #endregion
    }

Let's subscribe:

public void SubscribePresence(string sip)
        {
            PresenceSubscriptionPIDF presenceSubscription = new PresenceSubscriptionPIDF();
            SipEndpoint myEndpoint = _endPoint;
            RealTimeAddress cgAddress = new RealTimeAddress(sip);
            SipSubscription mySubScription = new SipSubscription(myEndpoint, cgAddress, "presence", presenceSubscription);
            mySubScription.BeginSubscribe(BeginSubscribeCallback, mySubScription);
        }
public void BeginSubscribeCallback(IAsyncResult asyncResult)
         {

             SipSubscription mySubscription = asyncResult.AsyncState as SipSubscription;
             try
             {
                 mySubscription.EndSubscribe(asyncResult);
  
             }
             catch (PublishSubscribeException)
             {
                 //Error("An exception occurred when unregistering the session.\n{0}", endpoint.ToString());
             }

             catch (RealTimeException)
             {
                 //Error("An exception occurred when unregistering the session.\n{0}", endpoint.ToString());
             }
         }

For more information/questions/remarks please contact me sip:marc.wetters@e-office.com

Tags van Technorati: ISipSubscriptionProcessor,Presence,PIDF,Marc Wetters,UCMA,Subscriptions