C# WWW Middleware

using System;
using System.Threading.Tasks;
using System.Text.RegularExpressions;

using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Extensions;
using Microsoft.AspNetCore.Builder;

using Microsoft.Extensions.Logging;


namespace Website.Middlewares
{

    public class WWWRedirectionMiddleware
    {
        private readonly RequestDelegate _next;
        private readonly ILogger _logger;

        private string _domain;
        private int _https_port;

        public WWWRedirectionMiddleware(RequestDelegate next, ILoggerFactory loggerFactory)
        {
            _next = next ?? throw new ArgumentNullException(nameof(next));
            _logger = loggerFactory.CreateLogger<WWWRedirectionMiddleware>();
        }

        public async Task InvokeAsync(HttpContext context)
        {

            var request = context.Request;
            var response = context.Response;

            var host = request.Host;

            if (Environment.GetEnvironmentVariable("ASPNETCORE_ENVIRONMENT") == "Development")
            {
                _domain = "localhost";
                _https_port = 5001;
            }
            else
            {
                _domain = "seaoftools.com";
                _https_port = 80;
            }

            // Redirect to www domain if url is home page
            if (host.Host.Equals(_domain, StringComparison.OrdinalIgnoreCase))
            {
                host = new HostString("www." + host.Host, _https_port);

                var redirectUrl = UriHelper.BuildAbsolute(
                    "https",
                    host,
                    request.PathBase,
                    request.Path,
                    request.QueryString);

                response.Redirect(redirectUrl, true);
                return;
            } // Redirect to non-www domain if url is with a subdomain
            else if (host.Value.StartsWith("www.", StringComparison.OrdinalIgnoreCase)
                     && Regex.Replace(host.Host, @"www.|" + _domain, String.Empty) != String.Empty)
            {
                host = new HostString(host.Host.Replace("www.", String.Empty), _https_port);

                var redirectUrl = UriHelper.BuildAbsolute(
                    "https",
                    host,
                    request.PathBase,
                    request.Path,
                    request.QueryString);

                response.Redirect(redirectUrl, true);
                return;
            }

            await _next.Invoke(context);
        }
    }

}