Question

Due to network architecture of our software, our application servers cannot connect directly to the web service of our customer. Because of this we have an integration server between the application servers and customer’s servers. This integration server hosts a proxy web service. The problem is that the necessary credentials and some other additional information needs to be passed from the database at our application server to our proxy web service at the integration server.

I wouldn’t want to pollute the API and pass the object containing credentials and additional information on each web service request. Additionally we have multiple integration servers which can be shut down at will so I cannot just initialize the web service with credentials and other information in a separate method because the subsequent web service requests might be passed to another integration server.

Is there a way to add some kind of SoapExtension which could be used to pass the information to my web service instance on each method? If not, is there something else I could do besides adding an argument to each web method and use that to pass the information?

Answer 1

The answer was actually quite obvious.

Firstly I need to create a class which is derived from SoapHeader. This class is used to store all credentials and other additional information. For easier explaining, let’s give this class a name CredentialContainer.

In the actual web service class we need to add a new public property of type CredentialContainer. The property in this example is named Container.

Lastly, we have to add new attribute called SoapHeader to each method with WebMethod attribute. This handles transferring the information passed in the header of SOAP message to our CredentialContainer instance. Because new web service instance is created for each web service request, there are no risk even with multiple concurrent web service requests.

Here’s the example code:

[WebService]
public class ExampleWebService
{
    public CredentialContainer Container { get; set; }

    [WebMethod]
    [SoapHeader("Container")]
    public void PerformSomething(string value)
    {
        var actualWebServiceClient = new MyWebServiceClient(Container.Url, ...);
        actualWebServiceClient.SendValue(value);
    }
}

public class CredentialContainer : SoapHeader
{
    public string Url { get; set; }
    ...
}