Set up Google OAuth 2.0 Authentication For Blogger and Retrieve Blog Posts

Installation 
Blogger APIs Client Library for Python
CMD> pip install --upgrade google-api-python-client 
Ref: developers.google.com

(base) C:\Users\ashish\Desktop>pip install oauth2client

(base) C:\Users\ashish\Desktop\blogger>pip show google-api-python-client
Name: google-api-python-client
Version: 1.12.3
Summary: Google API Client Library for Python
Home-page: https://github.com/googleapis/google-api-python-client/
Author: Google LLC
Author-email: googleapis-packages@google.com
License: Apache 2.0
Location: d:\programfiles\anaconda3\lib\site-packages
Requires: six, google-auth-httplib2, google-auth, google-api-core, uritemplate, httplib2
Required-by: 

(base) C:\Users\ashish\Desktop\blogger>pip show oauth2client
Name: oauth2client
Version: 4.1.3
Summary: OAuth 2.0 client library
Home-page: http://github.com/google/oauth2client/
Author: Google Inc.
Author-email: jonwayne+oauth2client@google.com
License: Apache 2.0
Location: d:\programfiles\anaconda3\lib\site-packages
Requires: pyasn1, six, rsa, pyasn1-modules, httplib2
Required-by: 

==  ==  ==  ==  ==

Basic structure of the "client_secrets.json" is as written below:

Ref: GitHub

{
  "web": {
    "client_id": "[[INSERT CLIENT ID HERE]]",
    "client_secret": "[[INSERT CLIENT SECRET HERE]]",
    "redirect_uris": [],
    "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    "token_uri": "https://accounts.google.com/o/oauth2/token"
  }
} 

Our "client_secrets.json" file looks like this:

{
  "installed":
  {
    "client_id": "0...9-a...z.apps.googleusercontent.com",
    "project_id": "banded...",
    "auth_uri": "https://accounts.google.com/o/oauth2/auth",
    "token_uri": "https://oauth2.googleapis.com/token",
    "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
    "client_secret": "2.....v",
    "redirect_uris": ["urn:ietf:wg:oauth:2.0:oob", "http://localhost"]
  }
} 

==  ==  ==  ==  ==

About authorization protocols 
Your application must use OAuth 2.0 to authorize requests. No other authorization protocols are supported. If your application uses Google Sign-In, some aspects of authorization are handled for you.

You can create "OAuth Client ID" from here: developers.google.com





You can also create a new "Project".

We will select already created "My Project".

We will select the "OAuth Client" as "Desktop App":





==  ==  ==  ==  ==

Error if the 'client_secrets.json' file is not present alongside "blogger.py":

(base) C:\Users\ashish\Desktop>python blogger.py
The client secrets were invalid:
('Error opening file', 'client_secrets.json', 'No such file or directory', 2)
WARNING: Please configure OAuth 2.0

To make this sample run you will need to populate the client_secrets.json file
found at:

   client_secrets.json

with information from the APIs Console [ https://code.google.com/apis/console ]. 

==  ==  ==  ==  ==

Error on placing "empty (0KB)" file named "client_secrets.json":

(base) C:\Users\ashish\Desktop\blogger>python blogger_v2.py
Traceback (most recent call last):
  File "blogger_v2.py", line 43, in [module]
    main(sys.argv)
  File "blogger_v2.py", line 12, in main
    scope='https://www.googleapis.com/auth/blogger')
  File "D:\programfiles\Anaconda3\lib\site-packages\googleapiclient\sample_tools.py", line 88, in init
    client_secrets, scope=scope, message=tools.message_if_missing(client_secrets)
  File "D:\programfiles\Anaconda3\lib\site-packages\oauth2client\_helpers.py", line 133, in positional_wrapper
    return wrapped(*args, **kwargs)
  File "D:\programfiles\Anaconda3\lib\site-packages\oauth2client\client.py", line 2135, in flow_from_clientsecrets
    cache=cache)
  File "D:\programfiles\Anaconda3\lib\site-packages\oauth2client\clientsecrets.py", line 165, in loadfile
    return _loadfile(filename)
  File "D:\programfiles\Anaconda3\lib\site-packages\oauth2client\clientsecrets.py", line 122, in _loadfile
    obj = json.load(fp)
  File "D:\programfiles\Anaconda3\lib\json\__init__.py", line 296, in load
    parse_constant=parse_constant, object_pairs_hook=object_pairs_hook, **kw)
  File "D:\programfiles\Anaconda3\lib\json\__init__.py", line 348, in loads
    return _default_decoder.decode(s)
  File "D:\programfiles\Anaconda3\lib\json\decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "D:\programfiles\Anaconda3\lib\json\decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0) 

==  ==  ==  ==  ==

Before authentication:

  C:\Users\ashish\Desktop\blogger>tree /f
  
  C:.
      blogger_v1.py
      client_secrets.json
  
  No subfolders exist 

After authentication (the authentication steps are shown below), a 'blogger.dat' file is created:

  C:\Users\ashish\Desktop\blogger>tree /f
  
  C:.
      blogger.dat
      blogger_v1.py
      client_secrets.json
  
  No subfolders exist 

==  ==  ==  ==  ==

When we run the application the application the first time, it opens the "Google's User Authentication" window to give access to the application to the Blogger for a Google account by logging into the respective Google Account. 





Last prompt will ask you to confirm your choice:



Once the sign-in is complete it opens a Broswer Window (our browser is Chrome) as shown below:



Message: Application flow has been completed

==  ==  ==  ==  ==

CODE V1 

#!/usr/bin/env python
# -*- coding: utf-8 -*-

"""Simple command-line sample for Blogger.
Command-line application that retrieves the users blogs and posts.

Usage:
  $ python blogger.py

You can also get help on all the command-line flags the program understands
by running:
  $ python blogger.py --help

To get detailed log output run:
  $ python blogger.py --logging_level=DEBUG
"""

from __future__ import print_function

import sys

from oauth2client import client
from googleapiclient import sample_tools


def main(argv):
  # Authenticate and construct service.
  service, flags = sample_tools.init(
      argv, 'blogger', 'v3', __doc__, __file__,
      scope='https://www.googleapis.com/auth/blogger')

  try:
      users = service.users()

      # Retrieve this user's profile information
      thisuser = users.get(userId='self').execute()
      print('This user\'s display name is: %s' % thisuser['displayName'])

      blogs = service.blogs()

      # Retrieve the list of Blogs this user has write privileges on
      thisusersblogs = blogs.listByUser(userId='self').execute()
      for blog in thisusersblogs['items']:
        print('The blog named \'%s\' is at: %s' % (blog['name'], blog['url']))

      posts = service.posts()

      # List the posts for each blog this user has
      for blog in thisusersblogs['items']:
        print('The posts for %s:' % blog['name'])
        request = posts.list(blogId=blog['id'])
        while request != None:
          posts_doc = request.execute()
          if 'items' in posts_doc and not (posts_doc['items'] is None):
            for post in posts_doc['items']:
              print('  %s (%s)' % (post['title'], post['url']))
          request = posts.list_next(request, posts_doc)

  except client.AccessTokenRefreshError:
    print ('The credentials have been revoked or expired, please re-run'
      'the application to re-authorize')

if __name__ == '__main__':
  main(sys.argv) 

==  ==  ==  ==  ==

(base) CMD>python blogger_v1.py
D:\programfiles\Anaconda3\lib\site-packages\oauth2client\_helpers.py:255: UserWarning: Cannot access blogger.dat: No such file or directory
  warnings.warn(_MISSING_FILE_MESSAGE.format(filename))

Your browser has been opened to visit:
  https://accounts.google.com/o/oauth2/auth?client_id=1...

If your browser is on a different machine then exit and re-run this
application with the command-line parameter

  --noauth_local_webserver

Authentication successful.
This user's display name is: Ashish Jain
The blog named 'survival8' is at: http://survival8.blogspot.com/
The blog named 'ashish' is at: http://ashish.blogspot.com/

The posts for survival8:
  Difficult Conversations. How to Discuss What Matters Most (D. Stone, B. Patton, S. Heen, 2010) (http://survival8.blogspot.com/2020/09/douglas-stone-b-patton-s-heen-difficult.html)
  ...
  Is having a water fountain a sensible thing to do? (http://survival8.blogspot.com/2016/11/is-having-water-fountain-sensible-thing_21.html)
  
The posts for ashish:
  ... 

==  ==  ==  ==  ==

'Cloud Resource Manager' Screenshot Showing Our Usage



==  ==  ==  ==  ==

References

GitHub

  % Blogger: google-api-python-client
  
  % blogger.py

Google API Console

  % Google API Console
  
  % Dashboard
 
  % Cloud Resource Manager
  
Documentation

  % Blogger APIs Client Library for Python
  
  % Blogger API: Using the API
  
  % Blogger API v3 (Instance Methods)
  
  % Blogger API v3 . posts (Instance Methods)