Python quickstart

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Quickstarts explain how to set up and run an app that calls a Google Workspace API.

Google Workspace quickstarts use the API client libraries to handle some details of the authentication and authorization flow. We recommend that you use the client libraries for your own apps. Before you can run the sample app, each quickstart requires that you turn on authentication and authorization. If you're unfamiliar with authentication and authorization for Google Workspace APIs, read the Authentication and authorization overview.

Create a Python command-line application that makes requests to the Postmaster Tools API.

Objectives

  • Set up your environment.
  • Install the client library.
  • Set up the sample.
  • Run the sample.

Prerequisites

To run this quickstart, you need the following prerequisites:

  • A Google account with Gmail enabled.

Set up your environment

To complete this quickstart, set up your environment.

Enable the API

Before using Google APIs, you need to enable them in a Google Cloud project. You can enable one or more APIs in a single Google Cloud project.
  • In the Google Cloud console, enable the Postmaster Tools API.

    Enable the API

Authorize credentials for a desktop application

To authenticate as an end user and access user data in your app, you need to create one or more OAuth 2.0 Client IDs. A client ID is used to identify a single app to Google's OAuth servers. If your app runs on multiple platforms, you must create a separate client ID for each platform.
  1. In the Google Cloud console, go to the Credentials page.

    Go to Credentials

  2. Click Create Credentials > OAuth client ID.
  3. Click Application type > Desktop app.
  4. In the Name field, type a name for the credential. This name is only shown in the Google Cloud console.
  5. Click Create. The OAuth client created screen appears, showing your new Client ID and Client secret.
  6. Click OK. The newly created credential appears under OAuth 2.0 Client IDs.
Make a note of these credentials because you need them later in this quickstart.

Install the Google client library

  • Install the Google client library for Python:

    pip install --upgrade google-api-python-client google-auth-httplib2 google-auth-oauthlib
    

Configure the sample

  1. In your working directory, create a file named quickstart.py.
  2. Include the following code in quickstart.py:

    from __future__ import print_function
    import pickle
    import os.path
    from googleapiclient.discovery import build
    from google_auth_oauthlib.flow import InstalledAppFlow
    from google.auth.transport.requests import Request
    from googleapiclient import errors
    
    # If modifying these scopes, delete the file token.pickle.
    SCOPES = ['https://www.googleapis.com/auth/postmaster.readonly']
    
    def main():
        """Shows basic usage of the PostmasterTools v1beta1 API.
        Prints the visible domains on user's domain dashboard in https://postmaster.google.com/managedomains.
        """
        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(port=0)
            # Save the credentials for the next run
            with open('token.pickle', 'wb') as token:
                pickle.dump(creds, token)
    
        service = build('gmailpostmastertools', 'v1beta1', credentials=creds)
    
        domains = service.domains().list().execute()
        if not domains:
            print('No domains found.')
        else:
            print('Domains:')
            for domain in domains['domains']:
                print(domain)
    
    if __name__ == '__main__':
      main()
    
    

Run the sample

  1. In your working directory, build and run the sample:

    python quickstart.py
    
  2. The first time you run the sample, it prompts you to authorize access:

    1. If you're not already signed in to your Google Account, you're prompted to sign in. If you're signed in to multiple accounts, select one account to use for authorization.
    2. Click Accept.

    Authorization information is stored in the file system, so the next time you run the sample code, you aren't prompted for authorization.

You have successfully created your first Python application that makes requests to the Postmaster Tools API.

Next steps