使用MetadataExchangeClient时设置凭据

Question

would appreciate some help with this - I feel I must be missing something obvious. I want to use the System.ServiceModel.Description.MetadataExchangeClient to retrieve information about a Web service. If the Web service is unsecured, then I have no problem, but if the Web service is a WCF service secured by Windows authentication, then I get an error along the lines of: Metadata contains a reference that cannot be resolved: 'http://server/Service.svc?WSDL'.

My code is fairly simple:

Uri endpointUri = new Uri("http://server/Service.svc?WSDL");
System.ServiceModel.Description.MetadataExchangeClient mexClient = new System.ServiceModel.Description.MetadataExchangeClient(endpointUri, System.ServiceModel.Description.MetadataExchangeClientMode.HttpGet);
mexClient.ResolveMetadataReferences = true;
System.Net.NetworkCredential mexNetworkCredentials = new System.Net.NetworkCredential(username, password, domain);
mexClient.HttpCredentials = mexNetworkCredentials;
System.ServiceModel.Description.MetadataSet metadataSet = mexClient.GetMetadata(endpointUri, System.ServiceModel.Description.MetadataExchangeClientMode.HttpGet);

Am I just missing something in the way that the client needs to specify authentication? I have googled around for a sample code, but nothing seems to match what I have in mind.

Here is the Web.config file (slightly redacted):

<?xml version="1.0"?>
<configuration>
    <configSections>
        <sectionGroup name="system.web.extensions" type="System.Web.Configuration.SystemWebExtensionsSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
            <sectionGroup name="scripting" type="System.Web.Configuration.ScriptingSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
                <section name="scriptResourceHandler" type="System.Web.Configuration.ScriptingScriptResourceHandlerSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
                <sectionGroup name="webServices" type="System.Web.Configuration.ScriptingWebServicesSectionGroup, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
                    <section name="jsonSerialization" type="System.Web.Configuration.ScriptingJsonSerializationSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="Everywhere"/>
                    <section name="profileService" type="System.Web.Configuration.ScriptingProfileServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
                    <section name="authenticationService" type="System.Web.Configuration.ScriptingAuthenticationServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
                    <section name="roleService" type="System.Web.Configuration.ScriptingRoleServiceSection, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" requirePermission="false" allowDefinition="MachineToApplication"/>
                </sectionGroup>
            </sectionGroup>
        </sectionGroup>
    </configSections>
    <connectionStrings>
        <remove name="db"/>
        <add name="db" connectionString="server=&quot;server&quot;;database=&quot;database&quot;;Integrated Security=SSPI;" providerName="System.Data.SqlClient="/>
    </connectionStrings>
    <system.web>
        <!--
          Set compilation debug="true" to insert debugging 
          symbols into the compiled page. Because this 
          affects performance, set this value to true only 
          during development.
      -->
        <compilation>
            <assemblies>
                <add assembly="System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=B77A5C561934E089"/>
                <add assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            </assemblies>
        </compilation>
    </system.web>
    <location path="." inheritInChildApplications="false">
        <system.web>
            <authentication mode="Windows"/>
            <pages>
                <controls>
                    <add tagPrefix="asp" namespace="System.Web.UI" assembly="System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
                </controls>
            </pages>
            <httpHandlers>
                <remove verb="*" path="*.asmx"/>
                <add verb="*" path="*.asmx" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
                <add verb="*" path="*_AppService.axd" validate="false" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
                <add verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" validate="false"/>
            </httpHandlers>
            <httpModules>
                <add name="ScriptModule" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            </httpModules>
        </system.web>
        <system.codedom>
            <compilers>
                <compiler language="c#;cs;csharp" extension=".cs" warningLevel="4" type="Microsoft.CSharp.CSharpCodeProvider, System, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089">
                    <providerOption name="CompilerVersion" value="v3.5"/>
                    <providerOption name="WarnAsError" value="false"/>
                </compiler>
            </compilers>
        </system.codedom>
        <system.webServer>
            <validation validateIntegratedModeConfiguration="false"/>
            <modules>
                <remove name="ScriptModule"/>
                <add name="ScriptModule" preCondition="integratedMode" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            </modules>
            <handlers>
                <remove name="WebServiceHandlerFactory-Integrated"/>
                <remove name="ScriptHandlerFactory"/>
                <remove name="ScriptHandlerFactoryAppServices"/>
                <remove name="ScriptResource"/>
                <add name="ScriptHandlerFactory" verb="*" path="*.asmx" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
                <add name="ScriptHandlerFactoryAppServices" verb="*" path="*_AppService.axd" preCondition="integratedMode" type="System.Web.Script.Services.ScriptHandlerFactory, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
                <add name="ScriptResource" preCondition="integratedMode" verb="GET,HEAD" path="ScriptResource.axd" type="System.Web.Handlers.ScriptResourceHandler, System.Web.Extensions, Version=3.5.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"/>
            </handlers>
        </system.webServer>
        <system.serviceModel>
            <bindings>
                <basicHttpBinding>
                    <binding name="SecuredHttpBinding" maxReceivedMessageSize="52428800">
                        <readerQuotas maxArrayLength="52428800"/>
                        <security mode="TransportCredentialOnly">
                            <transport clientCredentialType="Ntlm"/>
                        </security>
                    </binding>
                </basicHttpBinding>
            </bindings>
            <services>
                <service behaviorConfiguration="APIServiceBehavior" name="APIService">
                    <endpoint address="" binding="basicHttpBinding" bindingConfiguration="SecuredHttpBinding" name="IAPIService" contract="IAPIService" bindingNamespace="http://www.general.com/general/api/v1"/>
                </service>
                <service behaviorConfiguration="APIServiceBehavior" name="Com.IntApp.Walls.API.InternalAPIService">
                    <endpoint address="" binding="basicHttpBinding" bindingConfiguration="SecuredHttpBinding" name="IInternalAPIService" contract="IInternalAPIService" bindingNamespace="http://www.general.com/general/api/v1"/>
                </service>
            </services>
            <behaviors>
                <serviceBehaviors>
                    <behavior name="APIServiceBehavior">
                        <serviceMetadata httpGetEnabled="true"/>
                        <serviceDebug includeExceptionDetailInFaults="true"/>
                    </behavior>
                </serviceBehaviors>
            </behaviors>
        </system.serviceModel>
    </location>
</configuration>

Thanks for any help, Martin

Answer 1

I will answer my own question in the hopes that this will help someone else later. I enabled tracing on my client by adding the following block of XML to my App.config file:

  <system.diagnostics>
    <sources>
      <source name="System.ServiceModel"
              switchValue="Information, ActivityTracing"
              propagateActivity="true">
        <listeners>
          <add name="traceListener"
              type="System.Diagnostics.XmlWriterTraceListener"
              initializeData= "D:\log\Traces.svclog" />
        </listeners>
      </source>
    </sources>
  </system.diagnostics>

In examining the resulting trace log, I could see that exceptions were being thrown: first because my client had too low a setting for MaxReceivedMessageSize and then because the default settings for MaxNameTableCharCount and MaximumResolvedReferences were too low. I fixed these with code along the following lines:

BasicHttpBinding basicHttpBinding = new BasicHttpBinding(BasicHttpSecurityMode.TransportCredentialOnly);
basicHttpBinding.Security.Transport.ClientCredentialType = HttpClientCredentialType.Windows;
basicHttpBinding.MaxReceivedMessageSize = 52428800;
System.Xml.XmlDictionaryReaderQuotas xmlDictionaryReaderQuotas = new XmlDictionaryReaderQuotas();
xmlDictionaryReaderQuotas.MaxNameTableCharCount = 2147483647;
basicHttpBinding.ReaderQuotas = xmlDictionaryReaderQuotas;
System.ServiceModel.Description.MetadataExchangeClient mexClient = new System.ServiceModel.Description.MetadataExchangeClient(basicHttpBinding);
mexClient.MaximumResolvedReferences = 1000;
System.ServiceModel.Description.MetadataSet metadataSet = mexClient.GetMetadata(endpointUri, System.ServiceModel.Description.MetadataExchangeClientMode.HttpGet);

Hope this saves someone some time!