ConstantContact bad example

class ConstantContact{

    private $api_key;
    private $token;

    private $is_valid = false;

    private $url = 'https://api.constantcontact.com/v2/';

    # constructor simply sets some internal vars
    function __construct($api_key, $token){

        if(!is_string($api_key) || empty($api_key)) return;
        $this->api_key = $api_key;

        if(!is_string($token) || empty($token)) return;
        $this->token = $token;

        $this->is_valid = true;
    }

    # returns available contact lists
    function get_lists(){
        if(!$this->is_valid) return false;
        $url = $this->url.'lists/?api_key='.$this->api_key;

        $ctx = stream_context_create($this->get_auth_context());
        $result = json_decode(file_get_contents($url,0,$ctx));

        if(false===$result) return false;
        return (array)$result;

    }

    # adds a contact to specified list.
    # extra data is appended with array_merge_recursive()

    function add_contact($email, $list_id, $extra_data=array()){

        # standard input validation
        if(!is_email($email)) return false;
        if(!is_numeric($list_id) ) return false;
        if(!is_array($extra_data)) $extra_data = array();

        # prepare the data
        $d = array_merge_recursive($extra_data, array(
            'lists'=>array(array('id'=>"".$list_id)),
            'email_addresses'=>array( array(
                'email_address'=>$email,
                'opt_in_source'=>'ACTION_BY_OWNER',
                'confirm_status'=>'NO_CONFIRMATION_REQUIRED'
            ))
        ));

        # create the context
        $url = $this->url."contacts?api_key=".$this->api_key;
        $ctx = array_merge_recursive($this->get_auth_context(),array(
            'http'=>array(
                'content'=>''.json_encode($d)
            )
        ));
        $ctx['http']['method']="POST";
        $ctx['http']['header'].="\r\n".implode("\r\n", array(
            "Content-type: application/json",
            "Action-By: ACTION_BY_OWNER"
        ));

        $ctx = stream_context_create($ctx);
        return file_get_contents($url,0,$ctx);
    }

    # returns authentication context template for file_get_contents
    private function get_auth_context(){

        return array('http'=>array(
            'method'=>'GET','header'=>implode("\r\n",array(
                "Authorization: Bearer ".$this->token,
                "X-Originating-Ip: ".$_SERVER['REMOTE_ADDR']
            ))
        ));
    }

}



$coco = new ConstantContact("api_key", "token");
echo var_dump($coco->add_contact('test_'.time().'@test.ca',1));