how to do Curl -X POST -d in PHP

Question

I’m doing an integration with an api that brings real estate

In the documentation, it looks like this:

curl -X POST -d "client_id=1234&client_secret=abcd&grant_type=client_credentials" \
https://www.linkapi.com.br/oauth/token

However I do not know how to do in PHP, I did the way below, but returned empty({}bool(true)):

$client_id="1234";
$client_secret="abcd";
$url ="https://www.linkapi.com.br/oauth/token";

$process = curl_init($url);
$data = json_encode(array('grant_type' => 'client_credentials', 'client_id' => $client_id, 'client_secret' => $client_secret));
curl_setopt($process, CURLOPT_HTTPHEADER, array("Content-Type: application/json"));
curl_setopt($process, CURLOPT_POST, true);
curl_setopt($process, CURLOPT_POSTFIELDS, $data);
$resp = curl_exec($process);

Answer 1

The data is in x-www-form-urlencoded, and not in JSON.

-d "client_id=1234&client_secret=abcd&grant_type=client_credentials"

This is a urlencoded, and not a JSON.

---

To have exactly the same effect, you’d have to use:

$data = http_build_query(['grant_type' => 'client_credentials', 'client_id' => $client_id, 'client_secret' => $client_secret]);

$process = curl_init($url);
curl_setopt($process, CURLOPT_HTTPHEADER, ["Content-Type: application/x-www-form-urlencoded"]); // O -d utiliza `application/x-www-form-urlencoded` por padrão.
curl_setopt($process, CURLOPT_POST, true);
curl_setopt($process, CURLOPT_POSTFIELDS, $data);
curl_setopt($process, CURLOPT_RETURNTRANSFER, true); // Para "salvar" a resposta no curl_exec (o $resp).
$resp = curl_exec($process);

The only difference is the removal of json and the use of http_build_query.