Protocol Channel Example: Chunking
In my quick PDC recap I promised to post Yasser’s demo code. So before I digress: here is the code for a protocol chunking channel.
There is a lot more refinement to be added in order to make this production-level, but it’s a great illustration of the power and flexibility of a layered channel model. We have streaming over some Indigo transports (TCP/Named Pipe datagram, and HTTP requests and responses). However, these streams suffer from connections getting dropped mid-message, and need to be secured, routed, etc at the transport layer.
Yasser’s chunking channel nicely sidesteps all of these issues. By fragmenting/reassembling at the SOAP layer, each SOAP “chunk message” can be secured using WS-Security, reliably sent using WS-RM, and even transacted using WS-Transactions. Even better, this solution works for streaming a Message over any arbitrary transport. Which means you can write a simple streaming media server by adapting the chunking channel and using it in conjunction with a Udp multicast transport. Maybe I’ll mock one up next week even 
For those not on commnet, I’ve posted the slides from my PDC talk here. Enjoy!
February 8th, 2006 at 9:15 pm
[…] Enable streaming on your binding (either through TransferMode.Streamed on a transport or by using chunking at the top of your binding stack) […]
June 27th, 2007 at 1:07 am
Hi Kenny.
I’m writing a custom HTTP binding. Would you know if the following channel stack yields an IDuplexSessionChannel shape?
ReliableSessionBindingElement
TextMessageEncodingBindingElement
HttpTransportBindingElement
I’m implementing a WsHTTP custom binding for the chunking sample, but it fails with when I add the ChunkingBindingElement to the top of the BindingElementCollection. The error is “’WsHttpChunkingBinding’ doesn’t support creating any channel types”. The CanBuildChannelFactory and CanBuildChannelListener functions in ChunkingBindingElement always return false. I suspect the binding elements I have chosen for my test binding don’t support the IDuplexSessionChannel shape. I also get the same problem when I remove the ChunkingBindingElement and add a CompositeDuplexBindingElement element. Cheers.
July 15th, 2007 at 2:54 pm
In order to get duplex session from RM on top of HTTP you need to layer CompositeDuplex and OneWayBindingElement in between (see what WsDualHttpBinding generates for example). You can setup this binding stack for IDuplexSessionChannel over HTTP:
ReliableSessionBindingElement
CompositeDuplexBindingElement
OneWayBindingElement
TextMessageEncodingBindingElement
HttpTransportBindingElement
July 17th, 2007 at 12:11 am
Hello Kenny,
I’m trying to integrate ChunkingChannel with WsFederationHttpBinding.
Is it my stack:
…….
But it fails. Is it possible to do what I would?
Thanks in advance
August 2nd, 2007 at 2:33 pm
Your stack seems to be ellided. is Chunking at the top? Is it a duplex stack?
August 7th, 2007 at 12:19 pm
Hello Kenny,
I have the same problem as guys had. I try to use chunking for WSDualHttpBinding. I create binding elements from in the following way:
public override BindingElementCollection CreateBindingElements()
{
WSDualHttpBinding wsHttpBinding = new WSDualHttpBinding();
BindingElementCollection beCollection = wsHttpBinding.CreateBindingElements();
beCollection.Insert(6, be);
return beCollection;
//BindingElementCollection col = new BindingElementCollection();
//col.Add(new TransactionFlowBindingElement());
//col.Add(rsbe);
////col.Add(new TransportSecurityBindingElement());
//col.Add(SecurityBindingElement.CreateAnonymousForCertificateBindingElement());
//col.Add(cdbe);
//col.Add(owbe);
//col.Add(new WindowsStreamSecurityBindingElement());
//col.Add(encbe);
//col.Add(be);
//col.Add(httpbe);
//return col;
}
February 18th, 2008 at 10:33 am
[…] you want to use full WS-Security, then you would need app-level “chunking†or a chunking protocol at the […]