Pre authenticate web service request in C#

Question

I'm having a problem with calling a web service request in C#.

The service and request are working fine in Soap UI with the option 'Authenticate Preemptively' enabled (File, Preferences, HTTP Settings). Without this setting enabled the service returns a 'Java.Lang.NullPointerException'.

The problem I'm having is that I do not know how to enable this setting in a C# context.

I have a .NET 3.5 class library which holds a so called service reference to the specific service. This is a simple code snippet;

try
{
    CatalogService.CatalogChangeClient service = new CatalogService.CatalogChangeClient();
    service.ClientCredentials.UserName.UserName = "fancydress";
    service.ClientCredentials.UserName.Password = "47fda9cb4b51a9e";
    service.ClientCredentials.SupportInteractive = true;

    ProductUpdate[] products = new ProductUpdate[1];
    products[0] = new ProductUpdate();
    products[0].ProductCode = "00001";
    products[0].ProductDescription = "TestProduct";

    string result = service.UpdateProducts(products);
}
catch (Exception exception)
{
    Console.WriteLine(exception.Message);
}

Update after first reply.

The CatalogService.CatalogChangeClient class seems to implement the WCF abstract class

System.ServiceModel.ClientBase<TChannel>

End Update

Could anyone help me set this property?

please show more code esp. the interface `CatalogService.CatalogChangeClient` implements — Yahia, Aug 17 '11 at 08:00
It seems to be implementing the System.ServiceModel.ClientBase class from WCF: public partial class CatalogChangeClient : System.ServiceModel.ClientBase, Fancydress.ResourceAccess.MCSF.CatalogService.CatalogChange — Rob Maas, Aug 17 '11 at 08:40
From what i gather this is a problem in the .NET implementation it sends the request and only when it gets a 401 from the services resends with Credentials... your Java WebService doesn't seem to send 401 - although you should first confirm that is really the case (i.e. WireShark)... IF it is the case: to circumvent this I suspect you will have to use a different client (proxy) which can be "tricked" into sending the credentials always... — Yahia, Aug 17 '11 at 08:48
Yahia, you are spot on. Using WireShark I was able to confirm that the java webservice does not send a 401. So yes, I will need a different proxy which will send the credentials always. Thanks! — Rob Maas, Aug 17 '11 at 08:57

score 7 · Accepted Answer · edited Apr 24 '18 at 08:35

7

You could try and override the GetWebRequest method from your generated client stub. I have used this once and that solved my problem.

Look at the following URL:

http://www.eggheadcafe.com/community/wcf/18/10056093/consuming-webservices-and-http-basic-authentication.aspx

Scroll a bit down.

Here's the code from the link:

protected override System.Net.WebRequest GetWebRequest(Uri uri)
{
    HttpWebRequest request;
    request = (HttpWebRequest)base.GetWebRequest(uri);

    if (PreAuthenticate)
    {
        NetworkCredential networkCredentials =
            Credentials.GetCredential(uri, "Basic");

        if (networkCredentials != null)
        {
            byte[] credentialBuffer = new UTF8Encoding().GetBytes(
                networkCredentials.UserName + ":" +
                networkCredentials.Password);
            request.Headers["Authorization"] =
                "Basic " + Convert.ToBase64String(credentialBuffer);
        }
        else
        {
            throw new ApplicationException("No network credentials");
        }
    }
    return request;
}

edited Apr 24 '18 at 08:35

Jhon

582
7
28

answered Oct 26 '11 at 12:22

Nicklas Møller Jepsen

1,248
2
16
34

2

There's a good article at [.NET WebRequest.PreAuthenticate – not quite what it sounds like](http://www.west-wind.com/weblog/posts/2010/Feb/18/NET-WebRequestPreAuthenticate-not-quite-what-it-sounds-like) which describes your answer and other options in much more detail. – ChrisW Jul 12 '13 at 21:17
1

I think you need an extra space: request.Headers["Authorization"] = "Basic " + ... but otherwise +1 – Julia Hayward Jun 26 '15 at 15:43
@Julia Hayward - True,should've been there. – Amit Kumar Ghosh Jul 13 '15 at 11:09
3

Where is the `GetWebRequest` method? – Shimmy Weitzhandler Nov 17 '15 at 07:23
2

System.ServiceModel.ClientBase doesn't have GetWebRequest, so where did you made this override? – volfk May 10 '21 at 20:32

Pre authenticate web service request in C#

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