This Library makes it easy to use OAuth. It is also flexible in that you can specify any google service names and an optional scope. This is only required if your API is not yet in our list.
Project Key: MM5uQxqjwkMiuJW2zE50SgUF7jOZt2NQ8
1. In the script editor, click on Resources > Manage librairies...
2. In the Included Libraries window, insert the project key into the Find a Library textbox and click on the Select button.
3. Select the Stable version from the drop down list.
*Note that the Identifier is how you call the library.
4. In your code type: Oauthapp.
You will see the available choices in the autocomplete box.
The .getAuth method takes an apiName as its argument from the list below.
Google service names:
In this example you are going to call on the getAuth(apiName) method. You will then be asked to grant access to your app. After granting access you will be able to get your G+ posts.