Turn API Return to Object PHP

Question

My API returns a JSON that I would like to transform into a PHP object so that I can find a specific field in return. how can I do this?

My get

public function teste()
{
    $requestUrl='http://XXXXXX:XXX/api/login';
    $users = array("wts-authorization: XXX/XXx","content-type: application/json","accept: application/json");
    $ch = curl_init($requestUrl);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $users);
    $obj = curl_exec($ch);

}

My return

{"page":2,"per_page":6,"total":12,"total_pages":2,"data":[{"id":7,"email":"[email protected]","first_name":"Michael","last_name":"Lawson","avatar":"https://s3.amazonaws.com/uifaces/faces/twitter/follettkyle/128.jpg"},{"id":8,"email":"[email protected]","first_name":"Lindsay","last_name":"Ferguson","avatar":"https://s3.amazonaws.com/uifaces/faces/twitter/araa3185/128.jpg"},{"id":9,"email":"[email protected]","first_name":"Tobias","last_name":"Funke","avatar":"https://s3.amazonaws.com/uifaces/faces/twitter/vivekprvr/128.jpg"},{"id":10,"email":"[email protected]","first_name":"Byron","last_name":"Fields","avatar":"https://s3.amazonaws.com/uifaces/faces/twitter/russoedu/128.jpg"},{"id":11,"email":"[email protected]","first_name":"George","last_name":"Edwards","avatar":"https://s3.amazonaws.com/uifaces/faces/twitter/mrmoiree/128.jpg"},{"id":12,"email":"[email protected]","first_name":"Rachel","last_name":"Howell","avatar":"https://s3.amazonaws.com/uifaces/faces/twitter/hebertialmeida/128.jpg"}]}

I would like to treat as an object and use as follows

obj->first_name == "Michael"

Magento 2.3.3 Win10 Xampp

Answer 1

Solved this way

public function testeDeBanco() {

    $objectManager = \Magento\Framework\App\ObjectManager::getInstance(); // Instance of object manager
    $resource = $objectManager->get('Magento\Framework\App\ResourceConnection');
    $connection = $resource->getConnection();


    $tableName = $resource->getTableName('catalog_category_entity_varchar'); //gives table name with prefix
    $sql = "Select * FROM " . $tableName;
    $result = $connection->fetchAll($sql);
    foreach ($result as $e){
        if($e['value']=='watches'){
            echo "id:".$e['value_id'];
        }
    }