ApiClient.prototype._authenticate = function () {
    this.authlock = true;
    this._rpcRequest('user.login', {
        user: this.user,
        password: this.password
    }, function (err, res) {
        if (!err) {
            this.authid = res;
        }

        if (!this.version) {
            this._getApiVersion(function (err, res) {
                if (!err) {
                    this.version = res;
                }
                this.authlock = false;
                this._processPendingQueries(err);
            }.bind(this));
        }
        else {
            this.authlock = false;
            this._processPendingQueries(err);
        }
    }.bind(this));
};