Google Sheet example for credential encryption modification

quickstart.py

#  Modified to add cryptography from the spreadsheet example:
# https://developers.google.com/sheets/api/quickstart/python
# https://github.com/gsuitedevs/python-samples/blob/master/sheets/quickstart/quickstart.py
#
# Copyright 2018 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# [START sheets_quickstart]
from __future__ import print_function
import pickle
from cryptography.fernet import Fernet
import os.path
from googleapiclient.discovery import build
from google_auth_oauthlib.flow import InstalledAppFlow
from google.auth.transport.requests import Request

# If modifying these scopes, delete the file token.pickle.
SCOPES = ['https://www.googleapis.com/auth/spreadsheets.readonly']

# The ID and range of a sample spreadsheet.
SAMPLE_SPREADSHEET_ID = '1BxiMVs0XRA5nFMdKvBdBZjgmUUqptlbs74OgvE2upms'
SAMPLE_RANGE_NAME = 'Class Data!A2:E'



def load_decrypt_unpkl(fname, encrypt_key, protocol=3): 
     """ 
     :param fname: file to load and decode 
     :param encrypt_key: encryption key  
     :param protocol: default=3 pickle protocol version, using 3 as the version 4 is default in  python3.8 and 3 previous to py3.8 while GitLab 
 uses 3.7 for the build 
     :returns: Google Credentials object 
     """ 
     decryptor = Fernet(encrypt_key) 
     with open(fname, 'rb') as enc_token: 
         pkl_token = decryptor.decrypt(enc_token.read()) 
         token = pickle.loads(pkl_token) 
         return token 
          
          


def pkl_encrypt_save(gcreds, fname, encrypt_key,protocol=3):
     """
     As the Google Credentials object is not easy to handle, the easiest way to do it is using a pickled version
     Encryption is used to save
     :param gcreds: google credentials
     :param encrypt_key: encryption key
     :param protocol: default=3 pickle protocol version, using 3 as the version 4 is default in  python3.8 and 3 previous to py3.8 while GitLab
 uses 3.7 for the build
     :returns: pickled and encrypted
     """
     encoder = Fernet(encrypt_key)
     pkl_creds = pickle.dumps(gcreds, protocol=protocol)
     enc_pkl_creds = encoder.encrypt(pkl_creds)
     with open(fname, 'wb') as enc_token:
         enc_token.write(enc_pkl_creds)
     return enc_pkl_creds


# THIS SHOULD BE DONE SECURELY, here is just as an example:
ENC_KEY=b'6SyMleooZS64_qb9dnhH63cGDoFl2-Yc0z0otmCBabQ='

def main():
    """Shows basic usage of the Sheets API.
    Prints values from a sample spreadsheet.
    """
    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'):
        creds = load_decrypt_unpkl('token.pickle', ENC_KEY)
    # 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(port=0)
        # Save the credentials for the next run
        pkl_encrypt_save(creds, 'token.pickle', ENC_KEY)

    service = build('sheets', 'v4', credentials=creds)

    # Call the Sheets API
    sheet = service.spreadsheets()
    result = sheet.values().get(spreadsheetId=SAMPLE_SPREADSHEET_ID,
                                range=SAMPLE_RANGE_NAME).execute()
    values = result.get('values', [])

    if not values:
        print('No data found.')
    else:
        print('Name, Major:')
        for row in values:
            # Print columns A and E, which correspond to indices 0 and 4.
            print('%s, %s' % (row[0], row[4]))

if __name__ == '__main__':
    main()
# [END sheets_quickstart]