Using Streaming Subscriptions in Exchange 2010

Example

The following example from a console application shows how to create a streaming subscription and output the number of notification events in the response.

        static void SetStreamingNotifications(ExchangeServiceBinding esb)
        {
            // Subscribe to streaming notifications on the Inbox folder, and only listen
            // to new mail, created, and deleted events.
            SubscribeType subscribeType = new SubscribeType();
            StreamingSubscriptionRequestType streamingRequest = new StreamingSubscriptionRequestType();
            streamingRequest.EventTypes = new NotificationEventTypeType[] 
            { 
               NotificationEventTypeType.NewMailEvent, 
               NotificationEventTypeType.CreatedEvent, 
               NotificationEventTypeType.DeletedEvent
            };
            streamingRequest.SubscribeToAllFolders = true;
            streamingRequest.SubscribeToAllFoldersSpecified = true;
            subscribeType.Item = streamingRequest;

            SubscribeResponseType response = esb.Subscribe(subscribeType);

            // Create the XML file for the request.
            CreateXmlMessageTextFile(subscribeType, response);

            // Get the subscription ID from the response.
            SubscribeResponseMessageType subscribeResponseMessage = response.ResponseMessages.Items[0] as SubscribeResponseMessageType;
            String subscriptionid = subscribeResponseMessage.SubscriptionId;
        }

After the subscription ID is retrieved, use an asynchronous Web request and response to submit the GetStreamingEvents Operation request and wait for responses.

The following example shows how a GetStreamingEvents request is generated. The subscription ID is passed into the routine and a StringBuilder object is used to store the generated XML request.

static HttpWebRequest GenerateStreamingRequest(string subscriptionid)
        {
            HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create("https://CAS01.contoso.com/EWS/Exchange.asmx");
            // Set Credentials.
            request.Credentials = new NetworkCredential("User1", "pass@word1");

            // Prepare the SOAP string with the appropriate subscription ID.
            StringBuilder SoapStr = new StringBuilder();
            SoapStr.Append("<soap:Envelope xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\"");
            SoapStr.Append(" xmlns:m=\"https://schemas.microsoft.com/exchange/services/2006/messages\"");
            SoapStr.Append(" xmlns:t=\"https://schemas.microsoft.com/exchange/services/2006/types\"");
            SoapStr.Append(" xmlns:soap=\"https://schemas.xmlsoap.org/soap/envelope/\">\n");
            SoapStr.Append("  <soap:Header>\n");
            SoapStr.Append("    <t:RequestServerVersion Version=\"Exchange2010_SP1\" />\n");
            SoapStr.Append("  </soap:Header>\n");
            SoapStr.Append("  <soap:Body>\n");
            SoapStr.Append("    <m:GetStreamingEvents>\n");
            SoapStr.Append("      <m:SubscriptionIds>\n");
            SoapStr.Append("        <t:SubscriptionId>" + subscriptionid + "</t:SubscriptionId>\n");
            SoapStr.Append("      </m:SubscriptionIds>\n");
            SoapStr.Append("      <m:ConnectionTimeout>30</m:ConnectionTimeout>\n");
            SoapStr.Append("    </m:GetStreamingEvents>\n");
            SoapStr.Append("  </soap:Body>\n");
            SoapStr.Append("</soap:Envelope>\n");

            request.ContentType = "text/xml; charset=\"utf-8\"";
            request.Accept = "text/xml";
            request.Method = "POST";

            byte[] bytes = Encoding.UTF8.GetBytes(SoapStr.ToString());
            request.ContentLength = bytes.Length;

            using (Stream stm = request.GetRequestStream())
            {
                using (StreamWriter stmw = new StreamWriter(stm))
                {
                    stmw.Write(SoapStr.ToString());
                }
            }
            return request;
        }

The following example shows how to parse the response that is returned by the server. In this example, the XML is searched by using XPath to find all the nodes for specified events.

static void GetStreamingResponse(HttpWebResponse streamingresponse)
     {
            String result = "";
            using (streamingresponse)
            {
                StreamReader reader = new StreamReader(streamingresponse.GetResponseStream());
                result = reader.ReadToEnd();
            }

            // The following wrapper is needed for a multiple node error.
            result = "<MyStreamingResponse>" + result + "</MyStreamingResponse>";
            // Display the result - the returned text.
            Console.WriteLine("\n" + result);
            
            // Load the result into an XML document and set the root node.            
            XmlDocument doc = new XmlDocument();
            doc.Load(new StringReader(result));
            XmlNode root = doc.DocumentElement;
            // Add the namespace.
            XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
            nsmgr.AddNamespace("t", "https://schemas.microsoft.com/exchange/services/2006/types");
            
            // Using Xpath, search for the subscribed events.
            XmlNodeList nodeList1 = root.SelectNodes("//t:NewMailEvent", nsmgr);
            Console.WriteLine("NewMailEvents= " + nodeList1.Count.ToString());
            XmlNodeList nodeList2 = root.SelectNodes("//t:DeletedEvent", nsmgr);
            Console.WriteLine("DeletedEvents= " + nodeList2.Count.ToString());
            XmlNodeList nodeList3 = root.SelectNodes("//t:CreatedEvent", nsmgr);
            Console.WriteLine("CreatedEvents= " + nodeList3.Count.ToString());
     }

You can also use the XmlNodeList object to step through the collection of nodes to read additional information about each of the returned events.

See Also

Concepts

Other Resources