access drive with access token - php

Question

struggling to understand the oauth2 token and refresh token processes
ive got this code
$url = 'https://www.googleapis.com/oauth2/v3/token';
$data = array('client_id' => 'clientid', 'client_secret' => 'secret','refresh_token' => 'token','grant_type' => 'refresh_token');
$options = array(
'http' => array(
'header' => "Content-type: application/x-www-form-urlencoded",
'method' => 'POST',
'approval_prompt'=>'force',
'access_type'=>'offline',
'content' => http_build_query($data),
),
);
$context = stream_context_create($options);
$result = file_get_contents($url, false, $context);
that code above gives me an access token , and i followed this link suggested by one fellow stackoverflower, pinoyyid, BUT , im confunsed on how to correctly use the resulting access token to access drive and copy a file...
all the process ive seen usually involves $client = new Google_Client() and im not sure on how to use the whole POST http://..... thing, so basically i need to figure out if i use the access token i got with the code above in a new instance of google client, or i simply do a post to a url with necesary info ( which im not clear on also ) any help/clarification is appreciated guys really
EDIT #1
what i want to achieve is to allow the end user to access my drive via my webpage, to let them copy a spreadsheet in my drive , and access it via my website, to store data on the spreadsheet,the spreadsheet will always be on my drive, never on the end user
EDIT #2
code as per your posts is as follows, using the service account,,,,the files are inside that gmail account which i created on the api console a service account
<?php
require 'Google/autoload.php';
$client = new Google_Client();
// Replace this with your application name.
$client->setApplicationName("TEST");
// Replace this with the service you are using.
$service = new Google_Service_Drive($client);
// This file location should point to the private key file.
$key = file_get_contents($_SERVER['DOCUMENT_ROOT'] . '/number-privatekey.p12');
$user_to_impersonate = 'admin#testpr.com';
$cred = new Google_Auth_AssertionCredentials(
'number#developer.gserviceaccount.com',
array('https://www.googleapis.com/auth/drive'), ****//this here has to be drive not drive.file
$key,
'notasecret',
'http://oauth.net/grant_type/jwt/1.0/bearer',
$user_to_impersonate
);
$client->setAssertionCredentials($cred);
if ($client->getAuth()->isAccessTokenExpired()) {
$client->getAuth()->refreshTokenWithAssertion();
}
$originFileId = "longnumber";
$copyTitle = 'copied';
$newfile = copyFile($service, $originFileId, $copyTitle);
print_r($newfile);
function copyFile($service, $originFileId, $copyTitle)
{
$copiedFile = new Google_Service_Drive_DriveFile();
$copiedFile->setTitle($copyTitle);
try {
return $service->files->copy($originFileId, $copiedFile);
} catch (Exception $e) {
print "An error occurred: " . $e->getMessage();
}
return NULL;
}
?>
so got it working just now, ty all for your time guys really and edited my post to reflect the dang thing

Answer 1

If you want to give the end user access to your drive, you have to give your application authority to make API calls on behalf of a user (in this case you) in your domain. For this you have to set up a service account and generate a p12 key in the Google Developers Console. You have to enter the https://www.googleapis.com/auth/drive API scope in your Admin Console as well.
Full explanation and examples can be found here: https://developers.google.com/api-client-library/php/auth/service-accounts.
To achieve this you also need the Google API's client library: https://github.com/google/google-api-php-client (also mentioned in the Google manual).
Code example to let users make API calls on behalf of one of your accounts: https://developers.google.com/api-client-library/php/guide/aaa_oauth2_service