Google Drive API provides the revisions
resource so that you can download and publish file revisions. For more details
about revision terminology, see Changes and revisions overview.
Specify revisions to save from auto delete
Google Drive automatically deletes older revisions that are no longer of
interest to the user. To prevent this from happening, you can set the boolean
flag keepRevisionForever to true to mark revisions that you don't want
Drive to purge.
Download a revision
To download the latest revision, use the
files.download method. For more
information, see Manage long-running
operations.
Publish a revision
To publish a Docs, Sheets, and
Slides revision, set the published property for that file in
the revisions resource. This property can't
be set for Google Sites revisions using Drive API.
If the file is created in a Google Workspace domain, the
publishedOutsideDomain property indicates whether the revision is accessible
by anyone or if it's restricted to users of the domain. For Sites
files, this property indicates whether a type=anyone permission exists.
Published revisions don't reflect changes made to a file unless the
publishAuto property is set. If that property is set to true, newer
revisions of a file are automatically published, overwriting the previous ones.
This behavior is also controlled by the "Automatically re-publish when changes
are made" checkbox in the Drive UI. For Sites
files, publishAuto is always false.