WCF routing and service metadata

Question

I'm building a WCF router which needs to act as a proxy for a number of internal web services (WCF and ASMX). The routing part is fairly straight-forward, but I can't understand how the service metadata exchange would work in this solution.

In other words: how would a client obtain metadata for an internal service behind the router? Do I need to manually supply WSDL files to the consumer? Can I somehow setup the router to return the metadata for an appropriate internal service?

Or perhaps my architecture is completely wrong?

Answer 1

I see 2 options here:

1. It may be an option to create a "non-transparent" proxy, if you don't want to expose the internal addresses. The advantage is that you can do more than just routing messages (i.e. such proxy may serve as a "security boundary", unwrapping ciphered messages and passing them plain to the internal endpoint). It can also provide an "interoperable level", exposing a WCF service as simple SOAP using same datatypes/message XML structure. The downside is that you'll have to update its code along with the proxied services
2. You may implement a WSDL rewriter. With it, you can mask the internal service URL on-the-fly - depending on your conditions, a simple string replace may or may not suffice.

Refer to:

• Message Inspectors
• IWsdlExportExtension

Answer 2

The same "router service" can also be used to get the individual WSDL for internal services behind the router.

Check out this thread

Answer 3

Have you considered using a simple HTTP Proxy instead? All WCF using REST or SOAP are at their core HTTP requests. It seems like the routing functionality (which I am assuming you are basing on hostname, URL path or parameters) could be performed by proxying the HTTP request without needing to understand the contents. ASP.Net will do a fairly good job of sanitizing incoming requests on its own, but you could always add additional custom filtering as necessary.