How to use IRouteConstraint in FastEndpoints

Question

Anyone know how to use IRouteConstraint in FastEndpoints? I have a existing class implemented IRouteConstraint and want to reuse it when I migrate to FastEndpoints? (I use it to parse hashids)

Answer 1

you can register custom route constraints the same way you would with minimal apis:

var bld = WebApplication.CreateBuilder(args);
bld.Services
   .Configure<RouteOptions>(c => c.ConstraintMap.Add("hasXYZ", typeof(MyConstraint)))
   .SwaggerDocument()
   .AddFastEndpoints();

var app = bld.Build();
app.UseFastEndpoints()
   .UseSwaggerGen();
app.Run();

sealed class MyConstraint : IRouteConstraint
{
    public bool Match(HttpContext? httpContext, IRouter? route, string routeKey, RouteValueDictionary values, RouteDirection routeDirection)
    {
        if (!values.TryGetValue(routeKey, out var routeValue))
            return false;

        var routeValueString = Convert.ToString(routeValue, CultureInfo.InvariantCulture);

        return routeValueString is not null && routeValueString.StartsWith("xyz");
    }
}

sealed class MyEndpoint : EndpointWithoutRequest
{
    public override void Configure()
    {
        Get("test/{id:hasXYZ}");
        AllowAnonymous();
    }

    public override async Task HandleAsync(CancellationToken c)
    {
        await SendAsync(Route<string>("id"));
    }
}