can not retrieve values from cache in custom module

Question

I am building a module and I set the cache in the form function, which will be retrieved in the insert_new_email function.

I can retrieve the cached data in the form function, but I can not in the insert_new_email function.

Below is the class I use for my mod.email_blast.php file

class email_blast {

    public $return_data;

    /**
     * Constructor
     */
    public function __construct()
    {
        $this->EE =& get_instance();
        $this->EE->load->library('session');
        if (!class_exists('MCAPI'))
        {
            require PATH_THIRD.'email_blast/libraries/MCAPI.php';
        }
    }

    // ----------------------------------------------------------------

    public function form() {
        $service = $this->EE->TMPL->fetch_param('service', false);
        $api_key = $this->EE->TMPL->fetch_param('api_key', false);
        $list_id = $this->EE->TMPL->fetch_param('list_id', false);

        if($api_key == FALSE || $list_id == FALSE) {
            return "You are missing parameter(s)";
        }

        $this->EE->session->set_cache('email_blast', 'api_key', $api_key);
        $this->EE->session->set_cache('email_blast', 'list_id', $list_id);
        $this->EE->session->set_cache('email_blast', 'service', $service);

        // Build an array to hold the form's hidden fields
        $hidden_fields = array(
            'ACT'       => ee()->functions->fetch_action_id('Email_blast', 'insert_new_email'),
            'RET'       => ee()->functions->fetch_current_uri(),
            'API_KEY'   => $this->EE->session->cache('email_blast', 'api_key')
        );

        // Build an array with the form data
        $form_data = array(
            "id" => $this->EE->TMPL->form_id,
            "class" => $this->EE->TMPL->form_class,
            "hidden_fields" => $hidden_fields,
        );

        // Fetch contents of the tag pair, ie, the form contents
        $tagdata = $this->EE->TMPL->tagdata;

        $form = $this->EE->functions->form_declaration($form_data) . 
            $tagdata . "</form>";

        return $form;
    } 

    function insert_new_email()
    {
        $email = ee()->input->get_post('email');
        $email = trim(strip_tags($email));
        $api_key = $this->EE->session->cache('email_blast', 'api_key');
        $api = new MCAPI($api_key);
        $merge_vars = array ("OPTINIP" => $_SERVER['REMOTE_ADDR']);
        $list_id = $this->EE->session->cache('email_blast', 'list_id');
        $result = $api->listSubscribe($list_id, $email, $merge_vars, 'html', 'false', 'true', 'false', 'true');

        $data = array(
            'title'     => 'Mailing list',
            'heading'   => 'Thank you',
            'content'   => $list_id,
            'link'      => array($_POST['RET'], 'Site name here'),
            'email'     => $email,
        );

        ee()->output->show_message($data);
    }
}

Answer 1

The session cache only lasts for a single page request. So by the time your action gets called, that cache is gone. You'd be better off adding those to the form as hidden fields, and then grabbing them from POST in your action.