问无法检索google Oauth2的刷新令牌

EN

  $url ="https://accounts.google.com/o/oauth2/token";
$fields = array(
   "client_id"=>"{your client id}",
   "client_secret"=>"{your client secret}",
   "refresh_token"=>"{your refresh token 1/.....}",
   "grant_type"=>"refresh_token"
);

$ch = curl_init($url);

//set the url, number of POST vars, POST data
curl_setopt($ch, CURLOPT_POST,count($fields));
curl_setopt($ch, CURLOPT_POSTFIELDS, $fields);
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);

//execute post
$lResponse_json = curl_exec($ch);

//close connection
curl_close($ch);