parse method
Implementation
DeviceInfo parse(Uri uri) {
var URLBase = doc.tagVal('URLBase').trim();
if (URLBase.isEmpty) {
URLBase = _urlBaseFromLocation(uri);
}
final device = _pickDevice();
return DeviceInfo(
URLBase,
_directText(device, 'deviceType'),
_directText(device, 'friendlyName'),
_services(device),
);
}