カテゴリー: CAPTCHA

securimage.php を解析してみる。

L:618行目付近 ”function check($code)”

function check($code)
{   
    // 考えながら検証する
    // $code: POSTしたデータ
    // echo $code;   // ←POSTしたデータ
    
    $this->code_entered = $code;
    $this->validate();
    return $this->correct_code;
}

L:1170付近 ”function validate()”

function validate()
{
    // retrieve code from session, if no code exists check sqlite database if supported.
    $code = '';

    if (isset($_SESSION['securimage_code_value']) && trim($_SESSION['securimage_code_value']) != '') {
        if ($this->isCodeExpired($_SESSION['securimage_code_ctime']) == false) { 
            $code = $_SESSION['securimage_code_value'];
        }
    } else if ($this->use_sqlite_db == true && function_exists('sqlite_open')) { // no code in session - may mean user has cookies turned off
        $this->openDatabase();
        $code = $this->getCodeFromDatabase();
    } else { /* session code invalid or non-existant and code not found in sqlite db or sqlite is not available */ }
    
    $code               = trim(strtolower($code));
    $code_entered       = trim(strtolower($this->code_entered));
    $this->correct_code = false;
    
    // echo '----------------'.$code_entered .'------------------';
    //$code_entered: 入力したデータを小文字にしたもの
    // echo $_SESSION['securimage_code_value'];
    // echo '===================';
    // echo $_SESSION['securimage_code_ctime'];
    
    
    if ($code != '') {
                if ($code == $code_entered) {
            $this->correct_code = true;
            $_SESSION['securimage_code_value'] = '';  // ← 照合する元データ
            $_SESSION['securimage_code_ctime'] = '';  // ← 照合する元データの生成時刻
            $this->clearCodeFromDatabase();
            }
    }
}