WCF: Concept of FLAT WSDL

Article
04/13/2015

Ask:

Java Client (Non.Net client) unable to consume the WCF service WSDL document.

Reason:

After collecting fiddler traces from client side, I see that there is a problem while trying to get the XSD downloaded.

WCF expose XSD via external location and sometime Java client may not be able to access them.

Fiddler Traces extract:

First request from svcutil.exe

GET https://XYZ.com.com/MyService/MyServiceFile.svc?wsdl
HTTP/1.1

Response, we do get the WSDL doc:

========

HTTP/1.1 200 OK

Content-Type: text/xml; charset=UTF-8

<?xml version="1.0" encoding="utf-8"?>

<wsdl:definitions
name="MyServiceFile" targetNamespace="tempuri.org/"
xmlns:wsdl="schemas.xmlsoap.org/wsdl/"
xmlns:wsx="schemas.xmlsoap.org/ws/2004/09/mex"
xmlns:wsa10="www.w3.org/2005/08/addressing"
xmlns:tns="tempuri.org/" xmlns:soap12="schemas.xmlsoap.org/wsdl/soap12/"
xmlns:wsu="docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-utility-1.0.xsd"
xmlns:wsp="schemas.xmlsoap.org/ws/2004/09/policy"
xmlns:wsap="schemas.xmlsoap.org/ws/2004/08/addressing/policy"
xmlns:msc="schemas.microsoft.com/ws/2005/12/wsdl/contract"
xmlns:wsa="schemas.xmlsoap.org/ws/2004/08/addressing"
xmlns:wsam="www.w3.org/2007/05/addressing/metadata"
xmlns:wsaw="www.w3.org/2006/05/addressing/wsdl"
xmlns:soap="schemas.xmlsoap.org/wsdl/soap/"
xmlns:xsd="www.w3.org/2001/XMLSchema"
xmlns:soapenc="schemas.xmlsoap.org/soap/encoding/">

<wsp:Policy
wsu:Id="MyRoutingEndpoint_policy"><wsp:ExactlyOne><wsp:All><sp:TransportBinding
xmlns:sp="schemas.xmlsoap.org/ws/2005/07/securitypolicy"><wsp:Policy><sp:TransportToken><wsp:Policy><sp:HttpsToken
RequireClientCertificate="false"/></wsp:Policy></sp:TransportToken><sp:AlgorithmSuite><wsp:Policy><sp:Basic256/></wsp:Policy></sp:AlgorithmSuite><sp:Layout><wsp:Policy><sp:Strict/></wsp:Policy></sp:Layout></wsp:Policy></sp:TransportBinding></wsp:All></wsp:ExactlyOne>

</wsp:Policy>

<wsdl:types>

<xsd:schema
targetNamespace="tempuri.org/Imports">

<xsd:import
schemaLocation="XYZ.com.com/MyService/MyServiceFile.svc?xsd=xsd0"
namespace="tempuri.org/"/>

<xsd:import
schemaLocation="XYZ.com.com/MyService/MyServiceFile.svc?xsd=xsd1"
namespace="schemas.microsoft.com/2003/10/Serialization/"/>

<xsd:import
schemaLocation="XYZ.com.com/MyService/MyServiceFile.svc?xsd=xsd2"
namespace="schemas.microsoft.com/2003/10/Serialization/Arrays"/>

<xsd:import
schemaLocation="XYZ.com.com/MyService/MyServiceFile.svc?xsd=xsd3"
namespace="schemas.datacontract.org/2004/07/McAfeePortal.MyService"/>

<xsd:import
schemaLocation="XYZ.com.com/MyService/MyServiceFile.svc?xsd=xsd4"
namespace="schemas.datacontract.org/2004/07/McAfeePortal.PurchaseMailService"/>

</xsd:schema></wsdl:types><wsdl:message

Second: Because of wrong Schema location, we end up in sending the request to wrong address:

GET XYZ.com.com/MyService/MyServiceFile.svc?xsd=xsd0
HTTP/1.1

Because of this issue, my reference.cs file is blank.

Options:

Considering the requirement, the feature is added in latest and greatest WCF 4.5.

But what about client running on 4.0 ?

Solution:

Using WCF extensibility we can achieve this by implementing the - IWsdlExportExtension

public class MyFlatWsdl : IWsdlExportExtension,IEndpointBehavior

{

public void ExportContract(WsdlExporter exporter, WsdlContractConversionContext context)

{

//throw new NotImplementedException();

}

public void ExportEndpoint(WsdlExporter exporter, WsdlEndpointConversionContext context)

{

XmlSchemaSet schemaSet =exporter.GeneratedXmlSchemas;

foreach (System.Web.Services.Description.ServiceDescription wsdl in exporter.GeneratedWsdlDocuments)

{

List<XmlSchema> importsList = new List<XmlSchema>();

foreach(XmlSchema schema inwsdl.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 voidAddImportedSchemas(XmlSchema schema, XmlSchemaSet schemaSet, List<XmlSchema> importsList)

{

foreach (XmlSchemaImportimport in schema.Includes)

{

ICollectionrealSchemas = schemaSet.Schemas(import.Namespace);

foreach(XmlSchema ixsd in realSchemas)

{

if(!importsList.Contains(ixsd))

{

importsList.Add(ixsd);

AddImportedSchemas(ixsd, schemaSet, importsList);

}

private voidRemoveXsdImports(XmlSchema schema)

{

for (int i = 0; i < schema.Includes.Count; i++)

{

if(schema.Includes[i] is XmlSchemaImport)

schema.Includes.RemoveAt(i--);

}

void IEndpointBehavior.AddBindingParameters(ServiceEndpoint endpoint,System.ServiceModel.Channels.BindingParameterCollection
bindingParameters)

{

//throw new NotImplementedException();

}

void IEndpointBehavior.ApplyClientBehavior(ServiceEndpoint endpoint,System.ServiceModel.Dispatcher.ClientRuntime
clientRuntime)

{

//throw new NotImplementedException();

}

void IEndpointBehavior.ApplyDispatchBehavior(ServiceEndpoint endpoint,System.ServiceModel.Dispatcher.EndpointDispatcher
endpointDispatcher)

{

//throw new NotImplementedException();

}

void IEndpointBehavior.Validate(ServiceEndpoint endpoint)

{

//throw new NotImplementedException();

}

public class MyBehaviorExtension : BehaviorExtensionElement

{

public overrideType BehaviorType

{

get { return typeof(MyFlatWsdl); }

}

protected override object CreateBehavior()

{

MyFlatWsdl myBehavior = new MyFlatWsdl();

return myBehavior;

}

Config file changes:

     <extensions>
      <behaviorExtensions>
        <add name="MyEndPointBehavior" type="WcfService2.MyBehaviorExtension, WcfService2"/>
      </behaviorExtensions>
    </extensions>

       <service name="WcfService2.Service1">
        <endpoint address="" binding="basicHttpBinding" bindingConfiguration="" behaviorConfiguration="MyBeh"
          name="end" contract="WcfService2.IService1" />
      </service>

       <endpointBehaviors>
        <behavior name="MyBeh">
          <MyEndPointBehavior />
        </behavior>
      </endpointBehaviors>

 With above code/config changes we can easily expose WCF service with Flat WSDL in 4.0.

 FYI, in WCF 4.5 it is available as "SingleWSDL" option.

 Hope this help !

WCF: Concept of FLAT WSDL

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