filleduchaos / firebase-functions-gauth

Proof-of-concept of getting offline access to various Google API scopes for a serverless Firebase project.

firebase-functions-gauth

Proof-of-concept of getting offline access to various Google API scopes for a serverless Firebase project.

How to set up

You will need to have created a Firebase account and project, installed the Firebase CLI and logged in from the command line.

• Clone the project and change into the project directory
• Edit the .firebaserc file to point the default project to your Firebase project.
• This demo uses anonymous authentication to capture users, so you'll have to enable that for your project (from the Firebase console). Alternatively, you can change to and enable whatever sign-in you want.
• You will need to obtain your Google project's credentials and register your OAuth callback.

  • Go to your Google console.

  • Make sure your Firebase project is the current selected project.

  • Click on Enable APIs and Services, search for and enable the Calendar API.

  • From the APIs and Services side menu, navigate to the Credentials page.

  • Add the server secret key to your app configuration:

    firebase functions:config:set gauth.server_api_key=YOUR_SERVER_API_KEY

  • Under the OAuth 2.0 client IDs section, click on the web client that was auto created by Google.

  • Add the client ID and secret at the top of the page to your configuration with these commands:

    firebase functions:config:set gauth.client_id=YOUR_CLIENT_ID
    firebase functions:config:set gauth.client_secret=YOUR_CLIENT_SECRET

  • On the Google Developers' Console page, go to the Authorized Redirect URIs section and add https://<PROJECT_ID>.firebaseapp.com/google-oauth2-callback.

    • If you have your own domain connected to the project, don't forget to add https://<YOUR_DOMAIN>/google-oauth2-callback as well.

  • Save your changes

    • Optionally, you can go to the OAuth consent screen tab to customize the authorization screen that will be presented to users

  • From the command line, run firebase deploy to push the app live

That's it! :)

How to use

• Navigate to your hosted project URL, sign in (if necessary) and grant Google permissions
• If you check your Firebase database, you should see a __tokens__ ref that has a credentials object for your user ID (protected from non-admin read/write access)
• You can test the offline access by visiting https://<YOUR_PROJECT_DOMAIN>/list-events?userID=<A_USER_ID>. A list of the user's calendar events for the coming week should be returned as a JSON if they have granted access previously. Also, visiting https://<YOUR_PROJECT_DOMAIN>/add-event?userID=<A_USER_ID> will add an event at a random time in the upcoming week to the user's calendar.

More

Check out the react-app branch for a more robust client implemented in React.

I might be turning this into a full-fledged library, so stay tuned!