How to set OpenIdConnect option prompt ="login" from Controller in .net core 2 application?

Question

I'm using a .net core 2 application and have set OpenIDConnect options prompt parameter to consent in ConfigureServices method in Startup.cs

.AddOpenIdConnect(options =>
{
     options.prompt ="consent";
}

But in the initial login page I want to just use the prompt ="login" without consent screen.

In Controller page

            return Challenge(
                   new AuthenticationProperties { RedirectUri = 
                  Url.Action("Index") },
                  OpenIdConnectDefaults.AuthenticationScheme);

Is there any way to change the prompt parameter to "login" from controller. In the previous version we could do this using OwinContext.

HttpContext.GetOwinContext().Environment.Add("Prompt","login");

Any help is appreciated, thanks.

Answer 1

You can use the Items property to communicate arbitrary parameters:

var authenticationProperties = new AuthenticationProperties
{
    RedirectUri = Url.Action("Index")
};
authenticationProperties.Items["prompt"] = "login";
return Challenge(
    authenticationProperties,
    OpenIdConnectDefaults.AuthenticationScheme);

Then you will have to handle the OnRedirectToIdentityProvider event, something like this:

options.Events = new OpenIdConnectEvents
{
    OnRedirectToIdentityProvider = context =>
    {
        if (context.Properties.Items.TryGetValue("prompt", out string prompt))
        {
            context.ProtocolMessage.Prompt = prompt;
        }
        return Task.CompletedTask;
    }
};

It looks in the Items if there is a prompt value given, and if so, replaces the existing value with that.