Service Broker C# Wrapper Interface and Transactions

August 16th, 2008 by Mark Harris Leave a reply »

Service Broker has a really good C# wrapper interface that comes part of the samples on Codeplex. If you need to work with service broker objects in the managed world then I would recommend using the interface from the .

Most samples I have seen demonstrate communicating within a single database, and hence use the SqlTransaction Class The code below is an example of sending a message to a SSB Service  in a SqlTransaction.

   1: private void SendMsgToSSB()
   2: {
   3:     SqlConnection conn = null;
   4:     SqlTransaction tran = null;
   5:     Conversation dialog = null;
   6:     Service client = null;
   7:     string connString = "Persist Security Info = False; Integrated Security = True; Initial Catalog = MyServiceBrokerDB; Data Source = .; Connect Timeout = 30;"
   8:     try
   9:     {
  10:         conn = new SqlConnection(connString);
  11:         conn.Open();
  12:  
  13:         // Begin a transaction
  14:         tran = conn.BeginTransaction();
  15:  
  16:         // Create a service object
  17:         client = new Service("MyCoolService", conn, tran);
  18:         client.FetchSize = 1;
  19:  
  20:         // Begin a dialog with the MyCoolService
  21:         dialog = client.BeginDialog(
  22:             "MyCoolServiceTarget", null, "DEFAULT",
  23:             TimeSpan.FromMinutes(1), false, conn, tran);
  24:  
  25:         // Create request message
  26:         string outgoingBody = "my really cool msg that broker understands";
  27:         Message request = new Message("DEFAULT",
  28:                                       new MemoryStream(Encoding.UTF8.GetBytes(outgoingBody)));
  29:  
  30:         // Send the message to the service
  31:         dialog.Send(request, conn, tran);
  32:  
  33:         dialog.End(conn, tran);
  34:         tran.Commit(); 
  35:     }
  36:     catch (ServiceException svcEx)
  37:     {//deal with this pesky service exceptions
  38:     }
  39:     finally
  40:     {//clean up here close connections etc.
  41:     }
  42: }

But in scenarios where the transaction needs to be elevated from a lightweight transaction to one that needs the aid of the DTC the SqlTransaction object is not going to cut it for you.

With a simple change (in bold and italicized) you can then support enlisting in a Distributed Transaction.

   1: public void SendMsgToSSB()
   2: {
   3:     SqlConnection conn = null;
   4:     Conversation dialog = null;
   5:     Service client = null;
   6:     string ConnectionString = "Persist Security Info = False; Integrated Security = True; Initial Catalog = MyServiceBrokerDB; Data Source = .; Connect Timeout = 30;";
   7:     try
   8:     {
   9:         conn = new SqlConnection(ConnectionString);
  10:         if (conn.State != ConnectionState.Open)
  11:         {
  12:             conn.Open();
  13:         }
  14:         conn.EnlistTransaction(Transaction.Current);
  15:  
  16:         // Create a service object
  17:         client = new Service("MyCoolService", conn, null);
  18:         client.FetchSize = 1;
  19:  
  20:         // Begin a dialog with the MyCoolService
  21:         dialog = client.BeginDialog(
  22:             "MyCoolServiceTarget", null, "DEFAULT",
  23:             TimeSpan.FromMinutes(1), false, conn, null);
  24:  
  25:         // Create request message
  26:         string outgoingBody = "my really cool msg that broker understands";
  27:         Message request = new Message("DEFAULT",
  28:                                       new MemoryStream(Encoding.UTF8.GetBytes(outgoingBody)));
  29:  
  30:         dialog.Send(request, conn, null);
  31:         dialog.End(conn, null);
  32:     }
  33:     catch (ServiceException ex)
  34:     { //deal with the exception
  35:     }
  36:     finally
  37:     { //clean up
  38:     }
  39: }

 

Again this code has a small issue what about if there is no Transaction available then sending a message without a transaction could be a bad thing. With one more change its ready to support both scenarios.

   1: public void SendMsgToSSB()
   2:   {   SqlTransaction tran = null;
   3:       SqlConnection conn = null;
   4:       Conversation dialog = null;
   5:       Service client = null;
   6:       string ConnectionString = "Persist Security Info = False; Integrated Security = True; Initial Catalog = MyServiceBrokerDB; Data Source = .; Connect Timeout = 30;";
   7:       try
   8:       {
   9:           conn = new SqlConnection(ConnectionString);
  10:           if (conn.State != ConnectionState.Open)
  11:           {
  12:               conn.Open();
  13:           }
  14:           if (Transaction.Current != null)
  15:           {
  16:               conn.EnlistTransaction(Transaction.Current);
  17:           }
  18:           else
  19:           {
  20:               tran = conn.BeginTransaction();
  21:           }
  22:  
  23:           // Create a service object
  24:           client = new Service("MyCoolService", conn, null);
  25:           client.FetchSize = 1;
  26:  
  27:           // Begin a dialog with the MyCoolService
  28:           dialog = client.BeginDialog(
  29:               "MyCoolServiceTarget", null, "DEFAULT",
  30:               TimeSpan.FromMinutes(1), false, conn, null);
  31:  
  32:           // Create request message
  33:           string outgoingBody = "my really cool msg that broker understands";
  34:           Message request = new Message("DEFAULT",
  35:                                         new MemoryStream(Encoding.UTF8.GetBytes(outgoingBody)));
  36:  
  37:           dialog.Send(request, conn, null);
  38:           dialog.End(conn, null);
  39:           if (tran != null)
  40:           {
  41:               tran.Commit();
  42:           }
  43:       }
  44:       catch (ServiceException ex)
  45:       { //deal with the exception
  46:       }
  47:       finally
  48:       { //clean up 
  49:       }
  50:   }

 

I have also been making a few changes to the interface that I intend to publish shortly.

Advertisement

2 comments

  1. Quite inspiring,

    Thanks

  2. HHC says:

    I used the SQLBroker Interface and with the above sample was able to send the message to the queue too but am not able to receive it. The queue has the message. Any suggestions?

Leave a Reply