php中實用的文件上傳類

class upload{
    /**
     * html表單 input 域的 name 屬性，默認為'file'
    */
    var $file_field = 'file' ;
   
    /**
     * $_files 數組
    */
    var $file_array;
   
    /**
     * 保存路徑，默認為當前路徑
    */
    var $save_path = '';
   
    /**
     * 自定義文件名
    */
    var $define_name;   
   
    /**
     * 最終保存的文件名
    */
    var $name;
   
    /**
     * 文件大小，單位：字節
    */
    var $size;
   
    /**
     * 文件擴展名，不包含"."
    */
    var $ext;    
   
    /**
     * 允許上傳的文件類型，默認不限制
    */
    var $allow_ext = array();
   
    /**
     * 允許上傳的文件類型，默認不限制
    */
    var $allow_size = false;
   
    /**
     * 如果已存在同名文件，是否允許覆蓋，默認不覆蓋。
    */
    var $overwrite = false;
   
    /**
     * 錯誤提示
    */
    var $error_code;
   
    /**
     * 構造函數
    */
    public function __construct(){
        if(!is_uploaded_file($_files[$this->file_field]['tmp_name'])){
            die("非法上傳！");
        }else{
            $this->file_array = $_files[$this->file_field];
            $this->name = $this->getpro('name');
            $this->size = $this->getpro('size');
            $this->ext = $this->getpro('ext');   
        }
    }
   
   
    /**
     * 上傳操作函數
     * @abstract    上傳成功返回 true , 否則返回相應錯誤代碼
     * @return        string or bool
    */
    public function upload(){
        if(is_uploaded_file($this->file_array['tmp_name'])){   
               
            if(!empty($this->allow_ext)){
                if(!in_array($this->ext,$this->allow_ext)){
                    $this->error_code = "不允許上傳該類型文件！";   
                    return false;
                }
            }
           
            if(!@file_exists(iconv('utf-8','gbk',$this->save_path))){
                $this->error_code = "文件上傳目錄不存在！";
                return false;
            }
           
            if(!is_writable(iconv('utf-8','gbk',$this->save_path))){
                $this->error_code = "文件上傳目錄不可寫入！";
                return false;
            }
           
            if($this->overwrite==false && @file_exists(iconv('utf-8','gbk',$this->save_path.$this->name))){
                $this->error_code = "該文件已存在！";
                return false;
            }
           
            if($this->allow_size){
                if($this->size > $this->allow_size){
                    $this->error_code = "文件大小超過系統限制！";
                    return false;
                }
            }
           
            $result = @move_uploaded_file($this->file_array['tmp_name'],iconv("utf-8","gbk",$this->save_path.$this->getpro("name")));           
            if($result){
                return true;
            }else{
                switch($this->file_array['error']){
                    case 1:
                        $this->error_code = "上傳的文件超過了 upload_max_filesize 選項限制的值！";
                    break;
                    case 2:
                        $this->error_code = "上傳文件的大小超過了 max_file_size 選項指定的值！";
                    break;
                    case 3:
                        $this->error_code = "上傳過程被中斷！";
                    break;
                    case 4:
                        $this->error_code = "沒有文件被上傳！";
                    break;
                    case 6:
                        $this->error_code = "找不到臨時文件夾！";
                    break;
                    case 7:
                        $this->error_code = "文件寫入失敗！";
                    break;
                }
                return false;
            }
        }
    }
   
    /**
     * 上傳操作函數
     * @abstract    獲取文件屬性
     * @param        $itme:string類型，有效輸入為name(文件名)、ext(文件擴展名)、size(文件大小)
     * @return        string
    */
    public function getpro($item){
        switch($item){
            case "name":
                $filename = $this->file_array['name'];
                return isset($this->define_name) ? $this->define_name.".".$this->ext : $filename;
            break;   
            case "ext":
                $filename = $this->file_array['name'];
                $filter = explode(".",$filename);
                return strtolower($filter[count($filter)-1]);
            break;
            case "size":
                return $this->file_array['size'];
            break;
            default:
                die("非法操作！");
            break;
        }
    }
}