如何在php中使用文本文件验证要注册的电子邮件地址？

我有一个简单的php登录程序，使用平面文件，而不是SQL

我有以下php文件来验证电子邮件地址和密码：

<?php

    //check that the email and password form are submitted and not empty.   
    if(isset($_POST['register_button'])){//register button clicked
        if(isset($_POST['email']) && !empty($_POST['email']) AND isset($_POST['password']) && !empty($_POST['password'])){
            $email = trim(($_POST['email']));
            $password_before_hash = trim(($_POST['password']));
            if (!filter_var($email, FILTER_VALIDATE_EMAIL)){
                $msg = 'Please enter a valid email.';
            }elseif(strlen($password_before_hash)<6){
                $msg = 'Please enter a valid password.';
            }else{
//open a text file with email|hashed password|hashed token to check if a user already exists.
                $file1=fopen("validated.txt","r");
                $finduser=false;
                while(!feof($file1))
                {
                    $line = fgets($file1);
                    $array = explode("|",$line);
                    if(trim($array[0]) == $email)
                    {
                        $finduser=true;
                        break;
                    }
                }
                fclose($file1);
                
                if($finduser){//user found in validated list. User needs to login
                    $msg = 'Already registered. Please log in.';
                } else {//user never registered.
                    //hash password and token
                    $password = password_hash($_POST['password'], PASSWORD_DEFAULT); 
                    $hash = md5(rand(100,50000));
                    //write data into the text file in the form: email|hashed password|hased token.
                    $file2=fopen("unvalidated.txt","a");
                    fwrite($file2,"$email|$password|$hash");
                    fwrite($file2,"\n");
                    fclose($file2);
                    
                    $confirmed = false; //email not confirmed yet.
                    
                    
                    $to = $email;
                    $subject = 'validation';
                    $message = '
                    
                    Validate by clicking here:
                    (mydirectory)/validate.php?email='.$email.'&hash='.$hash.'
                    
                    ';
                    mail($to,$subject,$message);
                    
                    $msg = 'A validation email has sent to '. $email. '. Please follow the link.';
                    
            
                }
        
            }
    }else{
        $msg = 'Please fill in the information.';
    }

    }
?>

那么，我如何检查用户是否单击了电子邮件中的链接？我想将他们的电子邮件、哈希密码和哈希令牌放入文本文件

validated.txt

我该怎么办？请帮忙

Validate by clicking here:
                    (mydirectory)/validate.php?email=(myEmail)&hash=(randomHashValue)