As most of the information contained within Google drive is private user data. You must have an access token in order to access the information. Access tokens can be retrieved via the Oauth2 authentication process.
GET https://www.googleapis.com/drive/v2/files?access_token={Valid Access Token}
Response
{
"kind": "drive#fileList",
"etag": etag,
"selfLink": string,
"nextPageToken": string,
"nextLink": string,
"items": [
[files Resource][2]
]
}