Wcf – Can’t Access Net TCP service From WCF Test Client

nettcpbindingwcf

I'm trying to run two WCF services from within IIS one is a web service and one is a Net TCP Binding Service.

Here is a simulcrum of my Web.config (I've anonymized the service name):

<?xml version="1.0"?>
<configuration>

  <system.web>
    <compilation debug="true" targetFramework="4.0" />
  </system.web>
  <system.serviceModel>
    <services>
      <service name="ServerService">
        <endpoint address="ServerService" 
                  binding="netTcpBinding" 
                  bindingConfiguration="" 
                  name="NetTcpEndPoint" 
                  contract="IServerService">
          <identity>
            <dns value="localhost" />
          </identity>
        </endpoint>
        <endpoint address="mex"
                  binding="mexHttpBinding"
                  contract="IMetadataExchange" />
        <host>
          <baseAddresses>
            <add baseAddress="net.tcp://localhost:8523/"/>
            <add baseAddress="htt://localhost:8523/"/>
          </baseAddresses>
        </host>
      </service>

      <service name="MyWebService">
        <endpoint address=""
                  binding="wsHttpBinding"
                  bindingConfiguration=""
                  name="AACCWSEndPoint"
                  contract="IMyWebService">
          <identity>
            <dns value="localhost" />
          </identity>
        </endpoint>
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8523/IMyWebService"/>
          </baseAddresses>
        </host>
      </service>

    </services>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
          <serviceMetadata httpGetEnabled="true"/>
          <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
  </system.serviceModel>
 <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
  </system.webServer>

</configuration>

When I run this in the IDE it opens a page running on port 51953 and I can get the WSDL for the webservice by browsing to http://localhost:51953/WebService.svc?wsdl (Note the port is different).
I can't seem to get the WSDL by changing to port to what I've specified in the webconfig file (8523).

When I point the WcfTestClient app at "net.tcp://localhost:8523/ServerService and it gives me an error saying that it can't access the meta data, which as far as I can see I've configured (the second end point in the service).

What am I doing wrong here?

UPDATE:

I've tried changing the port number on the project properties to 8523 as suggested that didn't seem to work, I've also tried changint the address of the mex endpoint to "ServerService\mex" the test client spent some time churning but then it threw the following error:

Error: Cannot obtain Metadata from
net.tcp://localhost:8523/ServerService If this is a Windows (R)
Communication Foundation service to which you have access, please
check that you have enabled metadata publishing at the specified
address. For help enabling metadata publishing, please refer to the
MSDN documentation at
http://go.microsoft.com/fwlink/?LinkId=65455.WS-Metadata Exchange
Error URI: net.tcp://localhost:8523/ServerService Metadata
contains a reference that cannot be resolved:
'net.tcp://localhost:8523/ServerService'. You have tried to create
a channel to a service that does not support .Net Framing. It is
possible that you are encountering an HTTP endpoint. Expected
record type 'PreambleAck', found '72'.

I'm going to keep digging but I'd appreciate any help.

UPDATE 2:

I've changed the mex endpoint to a mexTcpBinding:
Here is the service tag:

    <endpoint address="ServerServiceWS"
              binding="wsHttpBinding"
              bindingConfiguration=""
              name="WSEndPoint"
              contract="IServerService">
      <identity>
        <dns value="localhost" />
      </identity>
    </endpoint>
    <endpoint address="mex"
              binding="mexTcpBinding"
              contract="IMetadataExchange" />
    <host>
      <baseAddresses>
        <add baseAddress="net.tcp://localhost:8523/"/>
        <add baseAddress="http://localhost:8523/"/>
      </baseAddresses>
    </host>
  </service>

Still no luck. Just to be sure I am entering the correct url into the tester the Url I am using is:

net.tcp://localhost:8523/ServerService

I've also Tried:

net.tcp://localhost:8523/mex

and

net.tcp://localhost:8523/

All of which give me some variation of the following error:

Error: Cannot obtain Metadata from
net.tcp://localhost:8523/ServerService If this is a Windows (R)
Communication Foundation service to which you have access, please
check that you have enabled metadata publishing at the specified
address. For help enabling metadata publishing, please refer to the
MSDN documentation at
http://go.microsoft.com/fwlink/?LinkId=65455.WS-Metadata Exchange
Error URI: net.tcp://localhost:8523/ServerService Metadata
contains a reference that cannot be resolved:
'net.tcp://localhost:8523/ServerService'. You have tried to create
a channel to a service that does not support .Net Framing. It is
possible that you are encountering an HTTP endpoint. Expected
record type 'PreambleAck', found '72'.

UPDATE 3

FWIW I think there might be a bigger problem with my WEb.config Here is what it currently looks like:

<?xml version="1.0"?>
<configuration>

  <system.web>
    <compilation debug="true" targetFramework="4.0" />
  </system.web>
  <system.serviceModel>
    <services>
      <service name="ServerService">
        <endpoint address="" 
                  binding="netTcpBinding" 
                  bindingConfiguration="DefaultBindingConfig" 
                  name="NetTcpEndPoint" 
                  contract="IServerService">
          <identity>
            <dns value="localhost" />
          </identity>
        </endpoint>

        <endpoint address="mex"
                  binding="mexTcpBinding"
                  contract="IMetadataExchange" 
                  bindingConfiguration="mexBinding"/>
        <host>
          <baseAddresses>
            <add baseAddress="net.tcp://localhost:8523/"/>
          </baseAddresses>
        </host>
      </service>

      <service name="MyWebService">
        <endpoint address=""
                  binding="wsHttpBinding"
                  bindingConfiguration=""
                  name="MyWSEndPoint"
                  contract="IMyWebService">
          <identity>
            <dns value="localhost" />
          </identity>
        </endpoint>
        <endpoint address="mex"
                  binding="mexHttpBinding"
                  contract="IMetadataExchange"
                  bindingConfiguration="mexHttpBinding"/>
        <host>
          <baseAddresses>
            <add baseAddress="http://localhost:8523/MyWebService"/>
          </baseAddresses>
        </host>
      </service>

    </services>
    <bindings>
      <netTcpBinding>
        <binding name="DefaultBindingConfig"
                 maxConnections="5"
                 portSharingEnabled="true" >
        </binding>
        <binding name="mexBinding"
                 portSharingEnabled="true">
          <security mode="None"></security>
        </binding>
      </netTcpBinding>
      <mexTcpBinding>
        <binding name="mexTcpBinding"/>
      </mexTcpBinding>
      <mexHttpBinding>
        <binding name="mexHttpBinding"/>
      </mexHttpBinding>
    </bindings>
    <behaviors>
      <serviceBehaviors>
        <behavior name="ServerServiceBehaviour">
          <!-- To avoid disclosing metadata information, set the value below to false and remove the metadata endpoint above before deployment -->
          <serviceMetadata httpGetEnabled="true" />
          <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
          <serviceDebug includeExceptionDetailInFaults="false"/>
        </behavior>
        <behavior name="MexBehaviour">
          <serviceMetadata httpGetEnabled="true" policyVersion="Policy15"/>
        </behavior>
      </serviceBehaviors>
    </behaviors>
    <serviceHostingEnvironment multipleSiteBindingsEnabled="true" />
  </system.serviceModel>
 <system.webServer>
    <modules runAllManagedModulesForAllRequests="true"/>
  </system.webServer>

</configuration>

I can browse to the Webservice and that allows me to get the WSDL using ?wsdl but if I put the Adddress http://localhost:8523/MyWebService into the WCF tester it throws an error too.

Error: Cannot obtain Metadata from http://localhost:8523/MyWebService
If this is a Windows (R) Communication Foundation service to which you
have access, please check that you have enabled metadata publishing at
the specified address. For help enabling metadata publishing, please
refer to the MSDN documentation at
http://go.microsoft.com/fwlink/?LinkId=65455.WS-Metadata Exchange
Error URI: http://localhost:8523/MyWebService Metadata contains
a reference that cannot be resolved:
'http://localhost:8523/MyWebService'. An error occurred while
receiving the HTTP response to http://localhost:8523/MyWebService.
This could be due to the service endpoint binding not using the HTTP
protocol. This could also be due to an HTTP request context being
aborted by the server (possibly due to the service shutting down). See
server logs for more details. The underlying connection was closed:
An unexpected error occurred on a receive. Unable to read data from
the transport connection: An existing connection was forcibly closed
by the remote host. An existing connection was forcibly closed by
the remote hostHTTP GET Error URI:
http://localhost:8523/MyWebService There was an error downloading
'http://localhost:8523/MyWebService'. The request failed with HTTP
status 404: Not Found.

I think the issue is either something to do with paths or I'm just putting the wrong URL into the test application. Either that or I've still not configured the meta data correctly.

Best Answer

For the HTTP endpoint, you need to reconfigure the Project Properties so that it starts your web.config defined endpoint at port 8523 if hosted using IIS Express. Use specific port (8523) instead of auto-assigned port (51953).

For the TCP metadata, you need to support a TCP-enabled mex endpoint (mexTcpBinding).

<endpoint address="mex" binding="mexTcpBinding" contract="IMetadataExchange" />

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C# – Catch-22 prevents streamed TCP WCF service securable by WIF; ruining the Christmas, mental health

WCF has gotchas in a few areas with streaming (I'm looking at you, MTOM¹) due to a fundamental issue in how it fails to perform preauthentication the way most people would think that should work (it only affects subsequent requests for that channel, not the first request) Ok, so this is not exactly your issue but please follow along as I will get to yours at the end. Normally the HTTP challenge works like this:

client hits server anonymously
server says, sorry, 401, I need authentication
client hits server with authentication token
server accepts.

Now, if you ever try to enable MTOM streaming on an WCF endpoint on the server, it will not complain. But, when you configure it on the client proxy (as you should, they must match bindings) it will explode in a fiery death. The reason for this is that the above sequence of events that WCF is trying to prevent is this:

client streams 100MB file to server anonymously in a single POST
server says sorry, 401, I need authentication
client again streams 100MB file to server with an authentication header
server accepts.

Notice that you just sent 200MB to the server when you only needed to send 100MB. Well, this is the problem. The answer is to send the authentication on the first attempt but this is not possible in WCF without writing a custom behaviour. Anyway, I digress.

Your Problem

First up, let me tell you that what you're trying is impossible². Now, in order for you to stop spinning your wheels, let me tell you why:

It strikes me that you are now wandering in a similar class of problem. If you enable message level security, the client must load the entire stream of data into memory before it can actually close out the message with the usual hash function and xml signature required by ws-security. If it has to read the entire stream to sign the single message (which is not really a message, but it's a single continuous stream) then you can see the problem here. WCF will have to stream it once "locally" to compute the message security, then stream it again to send it to the server. This is clearly a silly thing, so WCF does not permit message level security for streaming data.

So, the simple answer here is that you should send the token either as a parameter to the initial web service, or as a SOAP header and use a custom behaviour to validate it. You cannot use WS-Security to do this. Frankly, this is not just a WCF issue - I cannot see how it could practically work for any other stacks.

Solving the MTOM Problem

This is just for an example how I solved my MTOM streaming issue for basic authentication, so perhaps you could take the guts of this and implement something similar for your issue. The crux of it is that in order to enable your custom message inspector, you have to disable all notion of security on the client proxy (it remains enabled on the server,) apart from transport level (SSL):

this._contentService.Endpoint.Behaviors.Add(
    new BasicAuthenticationBehavior(
        username: this.Settings.HttpUser,
        password: this.Settings.HttpPass));
var binding = (BasicHttpBinding)this._contentService.Endpoint.Binding;
binding.Security.Mode = BasicHttpSecurityMode.Transport; // SSL only            
binding.Security.Transport.ClientCredentialType = 
   HttpClientCredentialType.None; // Do not provide

Note that I have turned off transport security here because I will be providing that myself using a message inspector and custom behaviour:

internal class BasicAuthenticationBehavior : IEndpointBehavior
{
    private readonly string _username;
    private readonly string _password;

    public BasicAuthenticationBehavior(string username, string password)
    {
        this._username = username;
        this._password = password;
    }
    public void AddBindingParameters(ServiceEndpoint endpoint, 
        BindingParameterCollection bindingParameters) { }
    public void ApplyClientBehavior(ServiceEndpoint endpoint,
        ClientRuntime clientRuntime)
    {
        var inspector = new BasicAuthenticationInspector(
            this._username, this._password);
        clientRuntime.MessageInspectors.Add(inspector);
    }
    public void ApplyDispatchBehavior(ServiceEndpoint endpoint,
        EndpointDispatcher endpointDispatcher) { }
    public void Validate(ServiceEndpoint endpoint) { }
}

internal class BasicAuthenticationInspector : IClientMessageInspector
{
    private readonly string _username;
    private readonly string _password;

    public BasicAuthenticationInspector(string username, string password)
    {
        this._username = username;
        this._password = password;
    }

    public void AfterReceiveReply(ref Message reply,
        object correlationState) { }

    public object BeforeSendRequest(ref Message request,
        IClientChannel channel)
    {
        // we add the headers manually rather than using credentials 
        // due to proxying issues, and with the 101-continue http verb 
        var authInfo = Convert.ToBase64String(
            Encoding.Default.GetBytes(this._username + ":" + this._password));

        var messageProperty = new HttpRequestMessageProperty();
        messageProperty.Headers.Add("Authorization", "Basic " + authInfo);
        request.Properties[HttpRequestMessageProperty.Name] = messageProperty;

        return null;
    }
}

So, this example is for anyone who is suffering with the MTOM issue, but also as a skeleton for you to implement something similar to authenticate your token generated by the primary WIF-secured token service.

Hope this helps.

(1) Large Data and Streaming

(2) Message Security in WCF (see "disadvantages.")

C# – How to solve System.ServiceModel.ServerTooBusyException in WCF

Check first if the App Pool is fine. If your application produces too much exceptions in a time period you would get the same error message.

In my experience often - if the relevant properties maxConcurrentInstances and maxConcurrentSessions are correctly set like here - it is something faulty in the web.config when this error occures.

Best Answer

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