[Feature Request] Leverage the new .WithCssRoutingHint in MSAL.NET 4.34.0

[jmprieur]

Is your feature request related to a problem? Please describe.

• Microsoft.Identity.Web:

  • currently uses it own extension methods to provide the routing hint.
  • uses the .WithHttpHeaders method:

    microsoft-identity-web/src/Microsoft.Identity.Web/TokenAcquisition.cs

    Line 178 in 9824659

    .WithExtraHttpHeaders(new Dictionary<string, string> { { Constants.XAnchorMailbox, ccsRoutingHint } });

• MSAL.ENT 4.33.0 retro-fitted a similar API

  public sealed class AcquireTokenByAuthorizationCodeParameterBuilder : 
    AbstractConfidentialClientAcquireTokenParameterBuilder<AcquireTokenByAuthorizationCodeParameterBuilder> {
        public AcquireTokenByAuthorizationCodeParameterBuilder WithCcsRoutingHint(string userName);
        public AcquireTokenByAuthorizationCodeParameterBuilder WithCcsRoutingHint(string userObjectIdentifier, string tenantIdentifier);
    }
    public sealed class AcquireTokenOnBehalfOfParameterBuilder : 
    AbstractConfidentialClientAcquireTokenParameterBuilder<AcquireTokenOnBehalfOfParameterBuilder> {
        public AcquireTokenOnBehalfOfParameterBuilder WithCcsRoutingHint(string userName);
        public AcquireTokenOnBehalfOfParameterBuilder WithCcsRoutingHint(string userObjectIdentifier, string tenantIdentifier);
    }
    public sealed class GetAuthorizationRequestUrlParameterBuilder : 
    AbstractConfidentialClientAcquireTokenParameterBuilder<GetAuthorizationRequestUrlParameterBuilder> {
        public GetAuthorizationRequestUrlParameterBuilder WithCcsRoutingHint(string userObjectIdentifier, string tenantIdentifier);
    }

Describe the solution you'd like

• Update the current code in Id.Web (still nice as it takes a ClaimsPrincipal), to use the new MSAL.NET 4.34.0 API
  

  microsoft-identity-web/src/Microsoft.Identity.Web/CcsHintExtensions.cs

  Lines 23 to 49 in 9824659

  	public static AbstractAcquireTokenParameterBuilder<T> WithCcsRoutingHint<T>(
  	this AbstractAcquireTokenParameterBuilder<T> builder,
  	ClaimsPrincipal? user)
  	where T : AbstractAcquireTokenParameterBuilder<T>
  	{
  	builder.WithExtraHttpHeaders(new Dictionary<string, string>
  	{
  	{ Constants.XAnchorMailbox, CreateCcsRoutingHintFromHttpContext(user) },
  	});
  	return builder;
  	}
  	internal static string CreateCcsRoutingHintFromHttpContext(ClaimsPrincipal? user)
  	{
  	if (user != null)
  	{
  	string? oid = user.GetObjectId();
  	string? tid = user.GetTenantId();
  	if (!string.IsNullOrEmpty(oid) && !string.IsNullOrEmpty(tid))
  	{
  	return $"oid:{oid}@{tid}";
  	}
  	}
  	return string.Empty;
  	}

• Use the new API instead of the .WithExtraHttpHeaders:
  

  microsoft-identity-web/src/Microsoft.Identity.Web/TokenAcquisition.cs

  Line 178 in 9824659

  .WithExtraHttpHeaders(new Dictionary<string, string> { { Constants.XAnchorMailbox, ccsRoutingHint } });

Describe alternatives you've considered
Leave the current code in Id.Web

[jennyf19]

Included in 1.15 release