Flatten your WSDL with this Custom ServiceHost for WCF - All About Interop - Site Home

Yesterday I mentioned using a custom service host to flatten the WSDL that is generated by a WCF service. This is something Christian showed us all how to do a long while ago, to improve interoperability between WCF-implemented services and consumers written on other technology stacks. Flattening WSDL is important for Interop purposes becausse many tools don't digest modular WSDL very well. When I say modular WSDL, I mean WSDL that imports other WSDL's or XSDs.

I realized that I had never actually published the code for my custom WCF service host that flattens WSDL.

So here it is. [updated 146pm US/Pacific time based on Natasa's comment]

using System;
using System.Collections;
using System.Collections.Generic;
using System.ServiceModel.Channels;
using System.ServiceModel.Description;
using System.ServiceModel.Dispatcher;
using System.Xml.Schema;
using ServiceDescription = System.Web.Services.Description.ServiceDescription;
 
namespace Thinktecture.ServiceModel
{
    public class FlatWsdl : IWsdlExportExtension, IEndpointBehavior
    {
        public void ExportContract(WsdlExporter exporter, WsdlContractConversionContext context) { }
 
        public void ExportEndpoint(WsdlExporter exporter, WsdlEndpointConversionContext context)
        {
            XmlSchemaSet schemaSet = exporter.GeneratedXmlSchemas;
            foreach (WsdlDescription wsdl in exporter.GeneratedWsdlDocuments)
            {
                List<XmlSchema> importsList = new List<XmlSchema>();
                foreach (XmlSchema schema in wsdl.Types.Schemas)
                    AddImportedSchemas(schema, schemaSet, importsList);
 
                if (importsList.Count == 0)
                    return;
 
                wsdl.Types.Schemas.Clear();
                foreach (XmlSchema schema in importsList)
                {
                    RemoveXsdImports(schema);
                    wsdl.Types.Schemas.Add(schema);
                }
            }
        }
 
        private void AddImportedSchemas(XmlSchema schema, XmlSchemaSet schemaSet, List<XmlSchema> importsList)
        {
            foreach (XmlSchemaImport import in schema.Includes)
            {
                ICollection realSchemas =
                    schemaSet.Schemas(import.Namespace);
 
                foreach (XmlSchema ixsd in realSchemas)
                {
                    if (!importsList.Contains(ixsd))
                    {
                        importsList.Add(ixsd);
                        AddImportedSchemas(ixsd, schemaSet, importsList);
                    }
                }
            }
        }
 
        private void RemoveXsdImports(XmlSchema schema)
        {
            for (int i = 0; i < schema.Includes.Count; i++)
            {
                if (schema.Includes[i] is XmlSchemaImport)
                    schema.Includes.RemoveAt(i--);
            }
        }
 
        public void AddBindingParameters(ServiceEndpoint endpoint, BindingParameterCollection bindingParameters) { }
 
        public void ApplyClientBehavior(ServiceEndpoint endpoint, ClientRuntime clientRuntime) { }
 
        public void ApplyDispatchBehavior(ServiceEndpoint endpoint, EndpointDispatcher endpointDispatcher) { }
 
        public void Validate(ServiceEndpoint endpoint) { }
    }
 
 
 
    public class FlatWsdlServiceHost : System.ServiceModel.ServiceHost
    {
        public FlatWsdlServiceHost() { }
 
        public FlatWsdlServiceHost(Type serviceType, params Uri[] baseAddresses)
            : base(serviceType, baseAddresses) { }
 
        public FlatWsdlServiceHost(object singletonInstance, params Uri[] baseAddresses)
            : base(singletonInstance, baseAddresses) { }
 
        protected override void ApplyConfiguration()
        {
            Console.WriteLine("ApplyConfiguration (thread {0})",
                              System.Threading.Thread.CurrentThread.ManagedThreadId);
            base.ApplyConfiguration();
            InjectFlatWsdlExtension();
        }
 
        private void InjectFlatWsdlExtension()
        {
            foreach (ServiceEndpoint endpoint in this.Description.Endpoints)            
                endpoint.Behaviors.Add(new FlatWsdl());
        }
    }
 
 
 
    public sealed class FlatWsdlServiceHostFactory : System.ServiceModel.Activation.ServiceHostFactory
    {
        public override System.ServiceModel.ServiceHostBase CreateServiceHost(string constructorString, Uri[] baseAddresses)
        {
            return base.CreateServiceHost(constructorString, baseAddresses);
        }
 
        protected override System.ServiceModel.ServiceHost CreateServiceHost(Type serviceType, Uri[] baseAddresses)
        {
            return new FlatWsdlServiceHost(serviceType, baseAddresses);
        }
    }
}

And to use this, you would specify something like this in your .svc file:

<%@ ServiceHost
    Language="C#"
    Factory="Thinktecture.ServiceModel.FlatWsdlServiceHostFactory"
    Service="Ionic.Samples.Webservices.WcfService1"%>