public function getMainText($file, $callback = null)
    {
        if(!is_null($callback))
        {
            $this->setCallback($callback);
        }

        return $this->request('text-main', $file);
    }
public function getMainText($file, $callback = null)
    {
        if(!is_null($callback))
        {
            $this->setCallback($callback);
        }

        return $this->request('text-main', $file);
    }
public function getMainText ( $ file , $ callback = null ) { if ( ! is_null ( $ callback ) ) { $ this -> setCallback ( $ callback ) ; } return $ this -> request ( 'text-main' , $ file ) ; }
Extracts main text

@param   string  $file
@param   mixed   $callback
@return  string
@throws  \Exception
Extracts main text