php验证码生成类

<?phpclass Upload {//确定属性private $_max_size;private $_ext_list= array('.jpg','.png','.gif');private $_allow_mine_list= array('image/pgn','image/gif','image/jpeg','image/pjpeg','image/x-png');private $_upload_path;private $_prefix;public function __construct(){$this -> setMaxsize(4*1024*1024);}//给出对应的set方法public function setMaxsize($max_size){$this->_max_size=$max_size;}public function setExtList(array $ext_list = array('.jpg','.png','.gif')){$this->_ext_list=$ext_list;}public function setAllowMimeList(array $allow_mine_list=array('image/pgn','image/gif','image/jpeg','image/pjpeg','image/x-png')){$this->_allow_mine_list=$allow_mine_list;}public function setUploadPath ($upload_path){$this->_upload_path=$upload_path;}public function setPrefix($prefix){$this->_prefix=$prefix;}public function doUpload($tmp_file){//判断文件大小，当文件过大时给出提示，放弃上传if($tmp_file['size']>$this->_max_size){echo '你上传的文件过大';return false ;}if(!($tmp_file['error']===0)){echo '上传文件有误';return false ;}//增加一段代码，用来校验上传的文件类型是否正确//上传文件的后缀统一转成小写$ext = strtolower(strrchr($tmp_file['name'],'.'));if(!in_array($ext, $this->_ext_list)){echo '你上传的文件类型不对';return false;}//对文件进行第二级防护，对上传文件的MIME进行验证$mime_type =$tmp_file['type'];if(!in_array($mime_type, $this->_allow_mine_list)){echo '你上传的文件的mime不对';return false;}//对文件类型进行第三级防护，使用PHP程序对文件类型进行MIME检测//为了使用Finfo这个类，需要开启php.ini中一个扩展：extension php_fileinfo.dll$finfo = new Finfo(FILEINFO_MIME_TYPE);$mime_type=$finfo->file($tmp_file['tmp_name']);if (!in_array($mime_type, $this->_allow_mine_list)){echo '类型不合法';return false;}//这里我们增加一段代码，让文件名唯一$filename = uniqid($this->_prefix,true);//拼接一个完整唯一的文件名$upload_filename=$filename.$ext;//增加分目录存放处理，记得在最后带上/$sub_dir = date('Ymd').'/';//判断这个目录是否存在if (!is_dir($this->_upload_path.$sub_dir)){//如果目录不存在，则创建一个新的mkdir($this->_upload_path.$sub_dir,0777,true);}if (move_uploaded_file(iconv('gbk','utf-8',$tmp_file['tmp_name']), iconv('utf-8','gbk',$this->_upload_path.$sub_dir.$upload_filename))){return $sub_dir.$upload_filename;}else{return false;}}}