Gmail API quickstart.py脚本返回KeyError'_module'

Question

I enabled the Gmail API and downloaded the .json file containing the token. I placed it in the same folder as the script. When I try to run it, I get this error:

Traceback (most recent call last):
  File "email_clean.py", line 14, in <module>
    creds = store.get()
  File "C:\Python27\lib\site-packages\oauth2client\client.py", line 407, in get
    return self.locked_get()
  File "C:\Python27\lib\site-packages\oauth2client\file.py", line 54, in locked_get
    credentials = client.Credentials.new_from_json(content)
  File "C:\Python27\lib\site-packages\oauth2client\client.py", line 302, in new_from_json
    module_name = data['_module']
KeyError: '_module'

I am aware that there are several other questions on SO for this same issue, but those solutions did not help me. The token.json file is in the same folder as the script, and the URL appears to be spelled correctly as best I can tell. The JSON file looks correctly formatted. Any help would be greatly appreciated.

Here is the script:

"""
Shows basic usage of the Gmail API.

Lists the user's Gmail labels.
"""
from __future__ import print_function
from apiclient.discovery import build
from httplib2 import Http
from oauth2client import file, client, tools

# Setup the Gmail API
SCOPES = 'https://www.googleapis.com/auth/gmail.readonly'
store = file.Storage('token.json')
creds = store.get()
if not creds or creds.invalid:
    flow = client.flow_from_clientsecrets('credentials.json', SCOPES)
    creds = tools.run_flow(flow, store)
service = build('gmail', 'v1', http=creds.authorize(Http()))

# Call the Gmail API
results = service.users().labels().list(userId='me').execute()
labels = results.get('labels', [])
if not labels:
    print('No labels found.')
else:
    print('Labels:')
    for label in labels:
        print(label['name'])

Answer 1

It's not finding / reading your token.json file. (You can look at that file and see it should have the first line read something like:

{"_module":  "oauth2client.client",
...

Simple fix (assuming your file has the correct info) is to pass the full absolute path name to file.Storage() , rather than just the file name.

In your case, you say your json file starts with

{"installed": {"client_id": ...

Thats's the your client secret json file, not the credentials json -- you'll need to use the former to get the latter. That file (with "installed" ) is the one to be used with your call to client.flow_from_clientsecrets() . On success, that will write the file as indicated by file.Storage() , and on subsequent attempts, the flow will look in the token file and use information in there (rather than clientsecrets).

A fix may be as simple as making sure your token.json file does not exist on first attempt as then it will attempt execute the flow & re-create the file.

A really good explanation of the flow is : Ashok Yogi's A beginners guide to Google OAuth and Google APIs

Answer 2

Figured it out. The problem was that I had saved the .json file as token.json, not realizing that this is a file that gets created once it authenticates. The trick was to delete token.json and then save the .json file from the Developer's Console as credentials.json.