SoupServer.vala

using GLib;

namespace SoupServer {
    
    class ServerApplication : Object {
        
        private Soup.Server server;
        
        public ServerApplication() {
            server = new Soup.Server(Soup.SERVER_PORT, 8000, null);
        }

        public void respond(Soup.Server server, Soup.Message msg,
          string path, HashTable? query, Soup.ClientContext client) {
            msg.set_status(Soup.KnownStatusCode.OK);
            msg.set_response("text/plain", Soup.MemoryUse.COPY,
              "TEST!", 4);
            return;
        }

        public void run() {
            server.add_handler("/", respond);
            server.run();
        }

        static int main(string[] args) {
            var app = new ServerApplication();
            app.run();
            return 0;
        }

    }

}