Choose Auth Scopes
Auth scopes express the permissions you request users to authorize for your app. While many Drive apps can function with just the required set of scopes, you may need to consider using other available scopes.
Google Drive scopes
Scopes available for the Drive API are:
||Per-file access to files created or opened by the app|
||Full, permissive scope to access all of a user's files. Request this
scope only when it is strictly necessary. Tokens with scope
||Allows apps read-only access to the list of Drive apps a user has installed.|
||Allows read-only access to file metadata and file content|
||Allows read-only access to file metadata, but does not allow any access to read or download file content|
||Special scope used to let users approve installation of an app|
||Allows access to the Application Data folder|
||Allows access to Apps Script files|
If your app requires access to any other Google APIs, you can add those scopes as well. For more information about Google API scopes, see Using OAuth 2.0 to Access Google APIs.
What scope or scopes does my app need?
As a general rule, choose the most restrictive scope possible, and avoid requesting scopes that your app does not actually need. Users more readily grant access to limited, clearly described scopes. Conversely, users may hesitate to grant broad access to their files unless they truly trust your app and understand why it needs the information.
strikes this balance in a practical way. Presumably, users only
open or create a file with an app that they trust, for reasons they
Requesting full drive scope for an app
Full access to all
files in the user's Drive (
may be necessary for some apps. An app designed to sync files, for
instance, needs this level of access to Drive. Apps with special
needs related to listing or reorganizing files might need full
Requesting drive-wide read-only scope for an app
access to all of a user's Drive files
https://www.googleapis.com/auth/drive.readonly) may be useful
for certain apps. For instance, a photo browser might need to
reorganize image files in a unique presentation order for a
slideshow, or a mobile app might have to work around unique display
constraints without needing to write anything. For apps that only
need to read file metadata for all files in Drive, there's
Requesting full drive scope during app development
One common and completely valid case for using full scope is iterative development. It may just be easier to avoid authorization-related constraints and use the full scope while testing your app during development. Then before you actually publish your app, you can back off to the file-level scope or whatever scope you really need for production operation.
Tips and tricks
To learn more about scopes, you can watch the following video of Google engineers
discussing related tips and tricks.