/**
* Test if a given bucket is writable. We will cache results in memcache as
* this is an expensive operation. This might lead to incorrect results being
* returned for this call for a short period while the result remains in the
* cache.
*/
private function isBucketWritable($bucket)
{
$cache_key_name = sprintf(parent::WRITABLE_MEMCACHE_KEY_FORMAT, $bucket);
$memcache = new \Memcache();
$result = $memcache->get($cache_key_name);
if ($result) {
return $result['is_writable'];
}
// We determine if the bucket is writable by trying to start a resumable
// upload. GCS will cleanup the abandoned upload after 7 days, and it will
// not be charged to the bucket owner.
$token_header = $this->getOAuthTokenHeader(parent::WRITE_SCOPE);
if ($token_header === false) {
return false;
}
$headers = array_merge(parent::$upload_start_header, $token_header);
$url = parent::createObjectUrl($bucket, parent::WRITABLE_TEMP_FILENAME);
$http_response = $this->makeHttpRequest($url, "POST", $headers);
if ($http_response === false) {
return false;
}
$status_code = $http_response['status_code'];
$is_writable = $status_code == HttpResponse::CREATED;
$memcache->set($cache_key_name, ['is_writable' => $is_writable], null, $this->context_options['writable_cache_expiry_seconds']);
return $is_writable;
}
