How to subscribe to changes on Google Drive using watch - google-drive-api

Question

I am quite stuck in trying to subscribe to changes on a google drive folder. My python3 code is as follows:
SCOPES = 'https://www.googleapis.com/auth/drive.readonly'
store = file.Storage('storage.json')
credentials = store.get()
if not credentials or credentials.invalid:
flow = client.flow_from_clientsecrets('client_id.json', SCOPES)
credentials = tools.run_flow(flow, store)
# This starts the authorization process
DRIVE = discovery.build('drive', 'v3', http=credentials.authorize(Http()))
try:
with open('saved_start_page_token.json') as json_data:
d = json.load(json_data)
try:
saved_start_page_token = d["startPageToken"]
except KeyError:
saved_start_page_token = d["newStartPageToken"]
print("Using saved token: %s" % saved_start_page_token)
except FileNotFoundError:
response = DRIVE.changes().getStartPageToken().execute()
with open("saved_start_page_token.json", "w") as token:
json.dump(response, token)
saved_start_page_token = response.get('startPageToken')
print('Start token: %s' % saved_start_page_token)
body = dict()
body["kind"] = "api#channel"
body["id"] = str(uuid.uuid4()) # TODO: do I have to do something with this channel id?
print(body["id"])
body["resourceId"] = 'web_hook'
body["resourceUri"] = 'https://meg-wm-it-change.appspot.com/notifications/'
json_body = json.dumps(body)
print(json_body)
request = DRIVE.changes().watch(pageToken = saved_start_page_token, body=json_body)
response = request.execute()
return response.body
Except this throws the error
googleapiclient.errors.HttpError: <HttpError 400 when requesting https://www.googleapis.com/drive/v3/changes/watch?pageToken=163958&alt=json returned "entity.resource">
Which I can't quite decipher. I'm sure my issue will be not understanding the documentation, (ie, I don't understand whether the params go versus the body of this request, and can't find any code samples) but any help would be appreciated!

Answer 1

I am going to post the answer I found to my own question in the event that anyone else wanders here:
# If modifying these scopes, delete the file token.pickle.
SCOPES = ['https://www.googleapis.com/auth/drive']
def auth():
creds = None
# The file token.pickle stores the user's access and refresh tokens, and is
# created automatically when the authorization flow completes for the first
# time.
if os.path.exists('token.pickle'):
with open('token.pickle', 'rb') as token:
creds = pickle.load(token)
# If there are no (valid) credentials available, let the user log in.
if not creds or not creds.valid:
if creds and creds.expired and creds.refresh_token:
creds.refresh(Request())
else:
flow = InstalledAppFlow.from_client_secrets_file(
'credentials.json', SCOPES)
creds = flow.run_local_server()
# Save the credentials for the next run
with open('token.pickle', 'wb') as token:
pickle.dump(creds, token)
return creds
def subscribe_changes(service):
channel_id = str(uuid.uuid4())
body = {
"id": channel_id,
"type": "web_hook",
"address": COOL_REGISTERED_DOMAIN
}
response = service.changes().watch(body=body, pageToken = get_page_token(service)).execute()
ts = response['expiration']
print(dateparser.parse(ts))
print(response)
return channel_id
def main():
creds = auth()
service = build('drive', 'v3', credentials=creds)
subscribe_changes(service)