How to get results from udemy api with search - php

Question

I have the same problem as here How to get results from Udemy Api with search? which unfortunately doesn't have an answer.
I'm able to retrieved the title etc, from this URL for example, https://www.udemy.com/api-2.0/courses/238934/?fields[course]=#all (you'll see the results in your browser) this URL works as well https://www.udemy.com/api-2.0/search-suggestions?q=java but not this one https://www.udemy.com/api-2.0/courses/?search=java
As mentioned here https://www.udemy.com/developers/affiliate/methods/get-courses-list/
get /api-2.0/courses/?search=java should work?
Here is my code:
$url = "https://www.udemy.com/api-2.0/courses/?search=java";
$ch = curl_init();
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_URL,$url);
$c_id = base64_encode('XXX');
$c_sid = base64_encode('XXX');
curl_setopt($ch,CURLOPT_HTTPHEADER,array('X-Udemy-Client-Id: '.$c_id.'','X-Udemy-Client-Secret: '.$c_sid.'',"Authorization: base64 encoded value of client-id:client-secret","Accept: application/json, text/plain, */*"));
curl_setopt($ch, CURLINFO_HEADER_OUT, true);
$result=curl_exec($ch);
curl_close($ch);
$result = json_decode($result);
$title = $result->title;
If someone could please shed some light on this.

Answer 1

Based on ADyson comments, here is the answer (just update the code with your own clientID and clientSecret ID from Udemy):
I've basically updated the CURLOPT_HTTPHEADER:
Code:
$url = "https://www.udemy.com/api-2.0/courses/?search=java";
$ch = curl_init();
curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_URL,$url);
//HTTP username.
$clientID = 'XXX';
//HTTP password.
$clientSecret = 'XXX';
//Create the headers array.
$headers = array(
'Content-Type: application/json',
'Authorization: Basic '. base64_encode("$clientID:$clientSecret")
);
//Set the headers that we want our cURL client to use.
curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
curl_setopt($ch, CURLINFO_HEADER_OUT, true);
$result=curl_exec($ch);
// echo curl_getinfo($ch, CURLINFO_HEADER_OUT);
// echo curl_getinfo($ch,CURLINFO_HTTP_CODE);
curl_close($ch);
$json = json_decode($result, true);
// return $result;
foreach($json['results'] as $results) {
$title = $results['title'];
echo $title.'<br>';
}
Results: (Course titles based on this search: https://www.udemy.com/api-2.0/courses/?search=java)
Java Programming Masterclass for Software Developers
Java Programming for Complete Beginners
Java In-Depth: Become a Complete Java Engineer!
The Complete Java Certification Course
Etc.