在file_get_contents中，保留session

設定完cookie即可

session_start();
$context = stream_context_create(array(
'http' => array(
 'method' => 'POST',
 'header' => "Content-Type: application/json\r\n".
 'Cookie: '.session_name().'='.session_id()."\r\n"
)));
session_write_close();