user2490003 user2490003 - 1 year ago 96
Python Question

Authorizing a python script to access the GData API without the OAuth2 user flow

I'm writing a small python script that will retrieve a list of my Google Contacts (using the Google Contacts API) and will randomly suggest one person for me to contact (good way to automate keeping in touch with friends!)

This is just a standalone script that I plan to schedule on a cron job. The problem is that Google seems to require OAuth2 style authentication, where the user (me) has to approve the access and then the app receives an authorization token I can then use to query the user's (my) contacts.

Since I'm only accessing my own data, is there a way to "pre-authorize" myself? Ideally I'd love to be able to retrieve some authorization token and then I'd run the script and pass that token as an environment variable

AUTH_TOKEN=12345 python

That way it doesn't require user input/interaction to authorize it one time.

Answer Source

The implementation you're describing invokes the full "three-legged" OAuth handshake, which requires explicit user consent. If you don't need user consent, you can instead utilize "two-legged" OAuth via a Google service account, which is tied to an application, rather than a user. Once you've granted permission to your service account to access your contacts, you can use the oauth2client ServiceAccountCredentials class to directly access GData without requiring user consent.

Here's the two-legged authentication example from the Google service account documentation:

import json

from httplib2 import Http

from oauth2client.service_account import ServiceAccountCredentials
from apiclient.discovery import build

scopes = ['']

credentials = ServiceAccountCredentials.from_json_keyfile_name(
        'service-account.json', scopes)

sqladmin = build('sqladmin', 'v1beta3', credentials=credentials)
response = sqladmin.instances().list(project='examinable-example-123').execute()

print response
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