How do I make a PATCH request in PHP using cURL?

Question

I have to make a PATCH request using PhP cURL. I couldn't find any documentation, so I tried the following but it isn't working.

$data = "{'field_name': 'field_value'}";
$url = "http://webservice.url";
$headers = array('X-HTTP-Method-Override: PATCH');
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_POST, 1);
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
$response = curl_exec($curl);
curl_close($curl);

Any idea why this isn't working? How can I fix it?

Edit: I am connecting to a RESTful web service. It returns HTTP/1.1 200 for successful requests. Unsuccessful requests return HTTP/1.1 403. I keep getting 403.

I tried changing $data to:

$data = "data={'field_name': 'field_value'}";

It didn't change the outcome.

Edit2: The final working code.

$data = "{'field_name': 'field_value'}";
$url = "http://webservice.url";
$headers = array('Content-Type: application/json');
$curl = curl_init();
curl_setopt($curl, CURLOPT_URL, $url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'PATCH');
curl_setopt($curl, CURLOPT_POSTFIELDS, $data);
curl_setopt($curl, CURLOPT_HTTPHEADER, $headers);
$response = curl_exec($curl);
curl_close($curl);

Answer 1

curl_setopt($curl, CURLOPT_CUSTOMREQUEST, 'PATCH'); should do it.