An external provider need to send a callback to our BizTalk environment. There callback is just a HTTP POST with an XML body.
Naturally we don't want to expose our BizTalk externally and we would like to go for a relay service in Azure.
As far as I can see there is not WebHttpRelayBinding in BizTalk. Is there some way around this or do I need to create a .NET service to handle this?
You can use WebHttpRelayBinding with the WCF Custom adapter. On a current project, we've configured the binding, together with the TransportClientEndpointBehavior and ServiceRegistrySettings behaviours, in machine.config. That allows us to easily configure the WCF Custom adapter as required.
This works fine, and supports Microsoft's approach to REST over the Relay Service. It doesn't quite solve our issues. We are dealing with AS2 traffic from a supplier. We receive XML payloads over AS2. That's OK. WebHttpRelay handles XML. The problem is that we need to return S/MIME acks (they are called MDNs in AS2) synchronously. To do that, we had to write a custom behaviour to handle 'raw' formatting in WCF. We have also had to write a couple of simple pipeline components to handle formatting and message property issues at the BizTalk end. We may evolve this by building a custom adapter using WCF, and refactor the pipeline component logic into the adapter at the service model level.
