Google API client authorization: Internal Server Error 500 - php

Question

I'm using an OAuth 2.0 for Web Server Applications example code on remote web server.
$client->authenticate(...) causes
Internal Server Error 500.
No idea why, can you help me please?
Here is the web address: http://imperiousgroup.com/gdrive/
And here is the code:
//index.php
require_once(__DIR__ ."/api/vendor/autoload.php");
session_start();
$client = new Google_Client();
$client->setAuthConfig('client_secrets.json');
$client->addScope(Google_Service_Drive::DRIVE_METADATA_READONLY);
if (isset($_SESSION['access_token']) && $_SESSION['access_token']) {
$client->setAccessToken($_SESSION['access_token']);
$drive_service = new Google_Service_Drive($client);
$files_list = $drive_service->files->listFiles(array())->getItems();
echo json_encode($files_list);
} else {
$redirect_uri = 'http://' . $_SERVER['HTTP_HOST'] . '/gdrive/oauth2callback.php';
header('Location: ' . filter_var($redirect_uri, FILTER_SANITIZE_URL));
}
//oauth2callback.php
require_once __DIR__ .'/api/vendor/autoload.php';
session_start();
$client = new Google_Client();
$client->setAuthConfigFile('client_secrets.json');
$client->setRedirectUri('http://' . $_SERVER['HTTP_HOST'] . '/gdrive/oauth2callback.php');
$client->addScope(Google_Service_Drive::DRIVE_METADATA_READONLY);
if (!isset($_GET['code'])) {
$auth_url = $client->createAuthUrl();
header('Location: ' . filter_var($auth_url, FILTER_SANITIZE_URL));
} else {
$client->authenticate($_GET['code']);
}

Answer 1

Which PHP version are you using?
I had a similar issue as I was using PHP 5.3 while the google api technically requires 5.4+.
If updating it is not an option, I was able to fix my specific issue by using the solution described here:
SO link
The call to curl_reset() is found in /vendor/guzzlehttp/guzzle/src/Handler/CurlFactory.php in the google api client folder.