Google DriveΒΆ
ownCloud uses OAuth 2.0 to connect to Google Drive. This requires configuration through Google to get an app ID and app secret, as ownCloud registers itself as an app.
All applications that access a Google API must be registered through the Google Cloud Console. Follow along carefully because the Google interface is a bit of a maze and it’s easy to get lost.
Note
Your ownCloud server must have a registered domain name and be accessible over the Internet; Google Drive will not connect to a LAN-only server.
If you already have a Google account, such as Groups, Drive, or Mail, you can use your existing login to log into the Google Cloud Console. After logging in click the Create Project button.

Give your project a name, and either accept the default Project ID or create your own, then click the Create button.

The next screen is your Project Dashboard. The Activities screen on the bottom left shows your current status. In the left sidebar click APIs & Auth > APIs, and then click Google Apps APIs > Drive API.

Before you click Enable API you might want to click on Learn more or Explore this API. Then click Enable API.

Enable API takes you to the Drive API dashboard, with tabs for Overview, Usage, Quota, and Drive UI Integration. Feel free to explore, and then go to APIs & Auth > Credentials. This screen has two sections: OAuth and Public API Access.

Click OAuth > Create New Client ID. The next screen that opens is Create Client ID. Check Web Application and click the Configure Consent Screen button. You’ll see the consent screen the first time you create a mountpoint for your Google Drive in ownCloud.

There are just a few required fields on the Consent Screen form: the email address of your Google account and your app name. The optional fields include your site URL, a link to your logo, and links to your privacy and terms of service policies. Your logo must be a hosted file because there is no upload dialogue. Click Save when you’re finished.

Now you should be on the Edit Client Settings screen. The Authorized JavaScript Origins is your root domain, for example https://www.example.com. You need two Authorized Redirect URIs, which must be in the following form:
https://example.com/owncloud/index.php/settings/personal
https://example.com/owncloud/index.php/settings/admin
Replace https://example.com/owncloud/ with your own ownCloud server URL, then click Save.

This should take you back to the OAuth screen, with a summary of your settings and editing buttons. This contains your Client ID and Client Secret, which you need to set up your ownCloud connection.

Go to your Admin page in ownCloud, create your new folder name, enter the Client ID and Client Secret, select your users and groups, and click Grant Access.

Google will open a dialogue asking for permission to connect to ownCloud. Click Accept. When you see the green light confirming a successful connection you’re finished.
See Configuring External Storage (GUI) for additional mount options and information.
See External Storage Authentication mechanisms for more information on authentication schemes.