I am trying to build a web UI for users to navigate his/her Google Drive and select one or more documents to be referenced later on in a website from a DB. I am currently bu
NB This answer uses the v2 API. New applications should write to the v3 API.
It is now possible to use the drive.files.list endpoint to list files belonging to a specific folder.
To do so, you can use the ?q= query parameter as follows:
GET https://www.googleapis.com/drive/v2/files?q="'' in parents"
In PHP, that would be
$service->files->list(array('q' => "'' in parents"));