source: TFP-WebServer/WebServer/src/WebAPI/APIs/Permissions/PermissionsApiHelpers.cs@ 451

using System;
using System.Net;

namespace Webserver.WebAPI.APIs.Permissions {
        public static class PermissionsApiHelpers {
                public static bool TryParseId (RequestContext _context, byte[] _jsonInputData, out PlatformUserIdentifierAbs _userId,
                        out string _groupId) {
                        string id = _context.RequestPath;
                        _userId = default;
                        _groupId = default;

                        if (string.IsNullOrEmpty (id)) {
                                WebUtils.SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, "NO_USER_OR_GROUP");
                                return false;
                        }

                        const string kindUserPrefix = "user/";
                        if (id.StartsWith (kindUserPrefix, StringComparison.Ordinal)) {
                                bool validId = PlatformUserIdentifierAbs.TryFromCombinedString (id.Substring (kindUserPrefix.Length), out _userId);
                                if (!validId) {
                                        WebUtils.SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, "INVALID_USER");
                                }

                                return validId;
                        }

                        const string kindGroupPrefix = "group/";
                        if (id.StartsWith (kindGroupPrefix, StringComparison.Ordinal)) {
                                _groupId = id.Substring (kindGroupPrefix.Length);
                                bool validId = _groupId.Length > 0;
                                if (!validId) {
                                        WebUtils.SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, "INVALID_GROUP");
                                }

                                return validId;
                        }

                        WebUtils.SendEmptyResponse (_context, HttpStatusCode.BadRequest, _jsonInputData, "INVALID_KIND");
                        return false;
                }
        }
}