How to connect to a Google Drive API and get the AccessToken - php

Question

I'm here with a little problem to connect my script with a Google Drive API using a credentials json file.
This is my code:
$oauth_credentials = __DIR__.'\credentials.json';
$redirect_uri = 'http://' . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF'];
$client = new Google\Client();
$client->setAccessType('offline');
$client->setAuthConfig($oauth_credentials);
$client->setRedirectUri($redirect_uri);
$client->addScope("https://www.googleapis.com/auth/drive");
if (isset($_GET['code'])) {
$token = $client->fetchAccessTokenWithAuthCode($_GET['code']);
var_dump($token);
}
Obviously I used composer to add google apiclient project to my script, and I used the cloud console of google to enable Drive API and create the credentials for this, and I used the credentials.json file downloaded of Google Console.
All is apparently good, I added a test account and used this account to accept permissions to use the Drive API.
Using the playground, in this URL https://developers.google.com/oauthplayground I test my credentials and I get the authorization code to create a refresh token and access token, but when i use this authorization code in my script the result is this: ""
'error' => string 'invalid_grant' (length=13)
'error_description' => string 'Bad Request' (length=11)
Any suggests? this code is exactly like the code appear in the Google examples.

Answer 1

My problem is that the focus is wrong way, I create a service account and generate the json credentials file and I use this code for upload a file:
putenv('GOOGLE_APPLICATION_CREDENTIALS=credentials.json');
$client = new Google_Client();
$client->useApplicationDefaultCredentials();
$client->setScopes(['https://www.googleapis.com/auth/drive.file']);
try {
$service = new Google_Service_Drive($client);
$file_path = 'example.txt';
$file = new Google_Service_Drive_DriveFile();
$file->setName('example.txt');
$file->setParents([$this->folder_id]);
$file->setDescription('Example description text');
$result = $service->files->create($file,[
'data' => file_get_contents($file_path),
'mimeType' => 'text/plain',
'uploadType' => 'text'
]);
echo 'Link to the uploaded file';
}
catch(Google_Service_Exception $gs)
{
$m = json_decode($gs->getMessage());
echo $m->error->message;
}
catch(Exception $e)
{
echo $e->getMessage();
}