Add example/demo for multiple or dynamic origins

[abergs]

A number of issues and pr's has been asked over the years to support either multiple origins, subdomains or dynamic origin validation configured at runtime.

All these can be supported by initiating a new instance of the library with the proper configuration. This can be done either with a new Fido2(new config...)) or through DI with the use of a factory.

We currently don't have too many easy to copy/paste examples of this, so perhaps we should add one.

Related:

• Support dynamic "origins" for this library for testing #538 (reply in thread)
• Wildcard orgin url feature #583

[namespacedevbox]

If you use Finbuckle.MultiTenant and a URL-based strategy where the ID is the origin, you can do it like this.

In Program.cs

builder.Services.AddScoped<IFido2Service, Fido2Service>();

In Fido2Service constructor

 private readonly Fido2 _fido2;

 public Fido2Service(IMultiTenantContextAccessor tenantAccessor)
 {
     var tenantInfo = tenantAccessor?.MultiTenantContext?.TenantInfo
         ?? throw new InvalidOperationException("Tenant information not resolved.");

     var origin = new Uri("https://" + tenantInfo.Identifier);

     _fido2 = new Fido2(new Fido2Configuration()
     {
         ServerDomain = origin.Host,
         ServerName = "My Identity",
         Origins = new HashSet<string> { origin.AbsoluteUri },
         TimestampDriftTolerance = 300000
     });
 }