将登录信息与外部文件php

Question

我有用户名和密码输入的html注册表。用户名和密码存储在.txt文件中，如下所示：

username1,password1  
username2,password2

我需要将输入的用户名和密码与存储的用户名和密码相匹配。这是我的代码，但有些东西不起作用，有人可以建议吗？

<form action = "./get_form.php" method = "post" name = "form" > 
    Username:
    <input type= "text" name = "username" >
    Password:
    <input type= "text" name = "passwords" >
    Remember me:
    <input type= "checkbox" name = "remember" value = "checked" >
    <input type = "submit" name = "submit" value= "Submit Query" >  
</form>


<?php

$username= $_POST["username"];
$password= $_POST["password"];
$contents = file("passwords.txt");
$found = false;

foreach ($contents as $line) {
    $data = explode(',', $line);   

    if (($username === $data[0]) && ($password === $data[1])) {
        $found = true;
    }
}
?>