Keeping HTTP Basic Authentification alive while being redirected

Question

We are using web service with basic authentication. It all worked all fine, till owners of web service implemented balancing service. Which is simply redirects requests to

Answer 1

Follow the MSDN for HttpWebRequest.AllowAutoRedirect Property i found this :

The Authorization header is cleared on auto-redirects and HttpWebRequest automatically tries to re-authenticate to the redirected location. In practice, this means that an application can't put custom authentication information into the Authorization header if it is possible to encounter redirection. Instead, the application must implement and register a custom authentication module. The System.Net.AuthenticationManager and related class are used to implement a custom authentication module. The AuthenticationManager.Register method registers a custom authentication module.

Solution is to write a custom Authentication Module.

Here what i've found about it :

http://msdn.microsoft.com/en-us/library/system.net.authenticationmanager.aspx

And here the AllowAutoRedirect properties page :

http://msdn.microsoft.com/en-us/library/system.net.httpwebrequest.allowautoredirect.aspx

UPDATE

Can you try to use CredentialCache instead of add header to webrequest ?

CredentialCache myCache = new CredentialCache();

myCache.Add(
new Uri("http://www.contoso.com/"),"Basic",new NetworkCredential(UserName,SecurelyStoredPassword));
req.Credentials = myCache;

Answer 2

Indeed, CredentialCache is working correctly. However, if you would like to add multiple basic auth credentials (for example if there is redirection that you are aware of) you can use following function that I have made:

private void SetNetworkCredential(Uri uriPrefix, string authType, NetworkCredential credential)
{
    if (request.Credentials == null)
    {
        request.Credentials = new CredentialCache();
    }

    if (request.Credentials.GetCredential(uriPrefix, authType) == null)
    {
        (request.Credentials as CredentialCache).Add(uriPrefix, authType, credential);
    }
}

I hope it will help somebody in the future.