Disallow bindings from other sources on optional claim binding.

So i want to bind the role from claim like this:

    [FromClaim(claimType: ClaimTypes.Role, false)]
    public string? Role { get; set; }

My goal is to do something role related if you have one. In the swagger document i got this: I dont want to bind the role from quary or other source, but i want it to be optional (some users dont have any role), thus the request returns a 400. I found this on the documantation: Is there a way to disable higher priority binding soruces for this property? Link: https://fast-endpoints.com/docs/model-binding#from-user-claims

[dj-nitehawk]

since swagger is a different universe, you’re gonna need a custom operation processor like this:

public class MyOperationProcessor : IOperationProcessor
{
    public bool Process(OperationProcessorContext ctx)
    {
        var apiDescription = ((AspNetCoreOperationProcessorContext)ctx).ApiDescription;
        var reqDtoType = apiDescription.ParameterDescriptions.FirstOrDefault()?.Type;
        var opParams = ctx.OperationDescription.Operation.Parameters;

        if (reqDtoType?.GetInterfaces().Contains(typeof(IHasRole)) is true)
        {
            foreach (var param in opParams.ToArray())
            {
                if (param.Name == nameof(IHasRole.Role))
                    opParams.Remove(param);
            }
        }
        return true;
    }
}

register it at startup like this:

builder.Services.AddSwaggerDoc(s => s.OperationProcessors.Add(new MyOperationProcessor()));

[szekelymatyas]

with v5.1.0-beta1 you can now do the following:

public interface IHasRole
{
    string? Role { get; set; }
}

public class Request : IHasRole
{
    public string? Role { get; set; }
}

app.UseFastEndpoints(c => c.Binding.Modifier = (req, tReq, ctx, ct) =>
{
    if (req is IHasRole r)
    {
        r.Role = ctx.HttpContext.User.ClaimValue(ClaimTypes.Role) ?? "Guest";
    }
});

I did almost the same thing with RequestBinder. I already started seaching a config to add request binder globally. Binding modifier is exactly what im looking for. Ty 😃