Google Drive API to identify the changes in files - google-drive-api

Question

I have a list of files and folder stored on a google drive folder. My objective is to identify any changes (modify/create/delete) related to any file/folder within a particular google drive folder i.e get the list of these file name and their drive path.
I have not registered any domain as our spring boot application is deployed on K8's pod and I do not want any notification on any domain or any webhook address. I only want the list of files being modified/deleted when I call the below method/api
Below is the code snippet for spring boot application.
#Component
public class DriveServiceProvider {
#Autowired
private DriveConfig dc;
public Drive getDriveService() throws IOException, GeneralSecurityException {
final GoogleCredentials credentials = GoogleCredentials
.fromStream(new ByteArrayInputStream(new JSONObject(dc.getCred()).toString().getBytes()))
.createScoped(Collections.singletonList("https://www.googleapis.com/auth/drive"));
HttpRequestInitializer requestInitializer = new HttpCredentialsAdapter(credentials);
return new Drive.Builder(GoogleNetHttpTransport.newTrustedTransport(), JacksonFactory.getDefaultInstance(), requestInitializer)
.setApplicationName(ApplicationConstants.APPLICATION_NAME).build();
}
}
Controller:
#RestController
#RequestMapping("/admin/watch")
public class TestGoogleWatchController {
#Autowired
private DriveServiceProvider driveServiceProvider;
#PostMapping(value = "/googleWatchNotification")
#ResponseStatus(HttpStatus.OK)
public Channel getNotification() throws IOException, GeneralSecurityException {
try {
StartPageToken pageToken = driveServiceProvider.getDriveService().changes().getStartPageToken().execute();
String savedStartPageToken = pageToken.getStartPageToken();
System.err.println(" savedStartPageToken "+savedStartPageToken );
while (savedStartPageToken != null) {
ChangeList changes = driveServiceProvider.getDriveService().changes().list(savedStartPageToken).execute();
System.err.println("======= changes " + changes.toPrettyString());
System.err.println("============ size ::" + changes.getChanges().size());
System.err.println("============ ChangeList ::" + changes.getChanges());
for (Change changeObj : changes.getChanges()) {
System.err.println(" files "+changeObj.getFileId() + " Kind "+changeObj.getKind() + ", Team Drive ID "+changeObj.getTeamDriveId() + ", Type::"+changeObj.getType()+ ",File ::"+changeObj.getFile()+ ", Is Removed::"+changeObj.getRemoved()+ ",Time ::"+changeObj.getTime());
}
}
}catch(Exception ex) {
}
return null;
}
}
*Below is the output after executing:
savedStartPageToken 165
======= changes {
"changes" : [ ],
"kind" : "drive#changeList",
"newStartPageToken" : "165"
}
============ size ::0
============ ChangeList ::[]*
The savedStartPageToken is printing incrementing numeric value after we change anything in drive, however there the ChangeList is always blank.

Answer 1

I am glad that I am answering my own question. The issue was that I was passing the current token in the changeList api.
Actually, the solution is to find the changes since last token till the current token using a loop.