asana getUserInfo error using PHP - php

Question

this is my code
<?php
require_once('asana.php');
$asana = new Asana(array('apiKey' => 'XXXXXXXX')); // API Key
$userinfo=$asana->getUserInfo();
if ($asana->responseCode != '200' || is_null($userinfo)) {
echo 'Error while trying to connect to Asana, response code: ' . $asana->responseCode;
return;
}
$resultJson = json_decode($userinfo);
foreach ($resultJson->data as $user) {
echo $user->name . ' (id ' . $user->id . ')' . PHP_EOL;
}
?>
In asana.php
public function getUserInfo($userId = null, array $opts = array()) {
$options = http_build_query($opts);
if (is_null($userId)) {
$userId = 'me';
}
return $this->askAsana($this->userUrl . '/' . $userId . '?' . $options);
}
And I got error like this: Notice: Trying to get property of non-object in C:\wamp\www\pngtest\index.php on line 15
What is the problem? Thanks in advance

Answer 1

$resultJson = json_decode($userinfo);
foreach ($resultJson->data as $user) {
}
You're trying to access $resultJson->data before you know if $resultJson is a valid object or not.
Note that json_decode returns:
NULL is returned if the json cannot be decoded or if the encoded data is deeper than the recursion limit.
It is possible (likely) that $resultJson is NULL, because it was given invalid JSON data. You should echo $userinfo and determine if it is what you expect.