CodeIgniter的CAPTCHA验证(CodeIgniter CAPTCHA validati

我创建了某种形式将数据插入到数据库和检查，如果数据是从人我用它已经集成到CI CAPTCHA发送。

这是我的控制器：

    $checkrules = array(
        'img_path' => realpath(APPPATH . '../upload/checking/img') . '/',
        'img_url' => base_url() . 'upload/checking/img/',
        'font_path' => realpath(APPPATH . '../upload/checking/font.ttf'),
        'img_width' => 150,
        'img_height' => 30,
        'expiration' => 7200
    );

    $check = create_captcha($checkrules);
    $data['checkimg'] = $check['image'];

    $this->form_validation->set_rules('name', 'Name', 'required|max_length[40]|xss_clean');
    $this->form_validation->set_rules('email', 'E-mail', 'required|valid_email|xss_clean');
    $this->form_validation->set_rules('website', 'Website', 'max_length[80]|prep_url|xss_clean');
    $this->form_validation->set_rules('comment', 'Comment', 'required|xss_clean');
    $this->form_validation->set_rules('check', 'Check', 'required|xss_clean');

    if ($this->form_validation->run() == FALSE)
    {
        $this->load->view('cms/theme', $data);
    }
    else
    {
        echo "success";
        $this->load->view('cms/theme', $data);
    }

我现在的问题是，什么是验证CAPTCHA的最佳方式？

1）创建的回调，我已经做了，但出现了问题，因为当我发送的形式是错误与新的验证码代码。

2）将CAPTCHA的代码转换成数据库并从中检查。问题是，因为会有很多加载数据库，这将是非常繁忙。

而第二个问题。难道这CAPTCHA只保存在文件夹.JPG图片，也可以是任何其他格式吗？（我问这个，因为我想删除使用后，他们此验证码是。）

Answer 1:

 * Example of captcha validation without database useage
 * Instead of it used session to store captcha value
 * The images will be deleted after the use

public function index()
{   
    $this->load->helper(array('form', 'url','captcha'));
    $this->load->library('form_validation');

       $this->form_validation->set_error_delimiters('<div class="error">', '</div>');
       $this->form_validation->set_rules('username', 'Username', 'trim|required|xss_clean');
       $this->form_validation->set_rules('password', 'Password', 'trim|required|xss_clean|callback_check_database');
       $this->form_validation->set_rules('captcha', 'Captcha', 'callback_validate_captcha');

    if($this->form_validation->run() == FALSE)
       {

        $original_string = array_merge(range(0,9), range('a','z'), range('A', 'Z'));
        $original_string = implode("", $original_string);
        $captcha = substr(str_shuffle($original_string), 0, 6);

         //Field validation failed.  User redirected to login page
        $vals = array(
                'word' => $captcha,
                'img_path' => './captcha/',
                'img_url' => 'http://mycodeignitor.org/captcha/',
                'font_path' => BASEPATH.'fonts/texb.ttf',
                'img_width' => 150,
                'img_height' => 50,
                'expiration' => 7200
        );

        $cap = create_captcha($vals);
        $data['image'] = $cap['image'];

        if(file_exists(BASEPATH."../captcha/".$this->session->userdata['image']))
            unlink(BASEPATH."../captcha/".$this->session->userdata['image']);

        $this->session->set_userdata(array('captcha'=>$captcha, 'image' => $cap['time'].'.jpg'));
        $this->load->view('index_index',$data);
       }
       else
       {
            if(file_exists(BASEPATH."../captcha/".$this->session->userdata['image']))
                unlink(BASEPATH."../captcha/".$this->session->userdata['image']);

            $this->session->unset_userdata('captcha');
            $this->session->unset_userdata('image');
            redirect('home', 'refresh');
       }



}

public function validate_captcha(){
    if($this->input->post('captcha') != $this->session->userdata['captcha'])
    {
        $this->form_validation->set_message('validate_captcha', 'Wrong captcha code, hmm are you the Terminator?');
        return false;
    }else{
        return true;
    }

}