$url="https://.../api.php?action=getThreads&hash=123fajwersa&node_id=4&order_by=post_date&order=‌​desc&limit=1&grab_content&content_limit=1";

//Using cURL
//  Initiate curl
$ch = curl_init();
// Will return the response, if false it print the response
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
// Set the url
curl_setopt($ch, CURLOPT_URL,$url);
// Execute
$result=curl_exec($ch);
// Closing
curl_close($ch);

// Will dump a beauty json :3
var_dump(json_decode($result, true));
//-------------------------------------------
//using file_get_contents
$result = file_get_contents($url);
// Will dump a beauty json :3
var_dump(json_decode($result, true));