php驗證碼生成類

<?php
    class Upload {
        //確定屬性
        private $_max_size;
        private $_ext_list= array('.jpg','.png','.gif');
        private $_allow_mine_list= array('p_w_picpath/pgn','p_w_picpath/gif','p_w_picpath/jpeg','p_w_picpath/pjpeg','p_w_picpath/x-png');
        private $_upload_path;
        private $_prefix;
        public function __construct()
        {
            $this -> setMaxsize(4*1024*1024);
        }
        //給出對應的set方法
        public function setMaxsize($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('p_w_picpath/pgn','p_w_picpath/gif','p_w_picpath/jpeg','p_w_picpath/pjpeg','p_w_picpath/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($tmp_file){
            //判斷文件大小，當文件過大時給出提示，放棄上傳
            if($tmp_file['size']>$this->_max_size){
                echo '你上傳的文件過大';
                return false ;
            }
            if(!($tmp_file['error']===0)){
                echo '上傳文件有誤';
                return false ;
            }
            //增加一段代碼，用來校驗上傳的文件類型是否正確
            //上傳文件的后綴統一轉成小寫
            $ext = strtolower(strrchr($tmp_file['name'],'.'));

            if(!in_array($ext, $this->_ext_list)){
                echo '你上傳的文件類型不對';
                return false;
            }
            //對文件進行第二級防護，對上傳文件的MIME進行驗證
            $mime_type =$tmp_file['type'];
            if(!in_array($mime_type, $this->_allow_mine_list)){
                echo '你上傳的文件的mime不對';
                return false;
            }
            //對文件類型進行第三級防護，使用PHP程序對文件類型進行MIME檢測
            //為了使用Finfo這個類，需要開啟php.ini中一個擴展：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 '類型不合法';
                return false;
            }
            //這里我們增加一段代碼，讓文件名唯一
            $filename = uniqid($this->_prefix,true);
            //拼接一個完整唯一的文件名
            $upload_filename=$filename.$ext;

            //增加分目錄存放處理，記得在最后帶上/
            $sub_dir = date('Ymd').'/';
            //判斷這個目錄是否存在
            if (!is_dir($this->_upload_path.$sub_dir)){
                //如果目錄不存在，則創建一個新的
                mkdir($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;
            }
        }
    }