Azure Devops Api - Detect if credentials are ok

In previous article of the series I’ve played with Azure DevOps api connection showing how you can use a .NET 4.8 full framework application that can login to Azure DevOps with a token or with an interactive login.

When you use interactive login, usually Windows operating system will retain credentials in credentials store, this will avoid asking for credential every time the application is run. The code that perform the check is really simple, it just check if _vssConnection.AuthorizedIdentity.DisplayName is not “anynymous”. This happens because the real credential check is done usually when you perform some real query, and not only the connection.

If you really need your software to verify if credentials are ok before doing everything else, you should try calling some api. Here is a possible code.

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try
{
    await _vssConnection.ConnectAsync();

    //Can try to force login to the server.
    if (string.IsNullOrEmpty(token) && "anonymous".Equals(_vssConnection.AuthorizedIdentity.DisplayName, StringComparison.OrdinalIgnoreCase))
    {
        var client = _vssConnection.GetClient<Microsoft.TeamFoundation.Core.WebApi.ProjectHttpClient>();
        await client.GetProjects();
    }
    return !"anonymous".Equals(_vssConnection.AuthorizedIdentity.DisplayName, StringComparison.OrdinalIgnoreCase);
}
catch (Exception ex)
{
    Log.Error(ex, "Error logging into the account");
}
return false;

This code is really simple, the problem is, after some time, cached credentials will expire, so you call ConnectAsync() and user DyplayName is “anonymous”. In this case I have no token (interactive login) and I cannot simply answer “login failed” because the connection failed due to expired cached credentials. The result is to call a simple api like GetProjects() that will trigger another interactive login.

Other posts in this series:

• Step 1: Connecting to the server
  • Step 1a: Detect if credentials are ok

Gian Maria.