Verifying if given Username already exist in a txt file, using php - php

Question

I have an assignment where i need to create a register page and verify if a user doesn't exist already in a txt file. I found some answers online and tried to apply them but doesn't seem to work for me. everything works except the part that he needs to verify.
here is my code: this is my code
<?php
if($_POST['formSubmit'] == "Submit")
{
$errorMessage ="";
$link_Create = "CreateAnAccount.php";
$Username = $_POST['userName'];
$password = $_POST['Password'];
if(empty($_POST['userName']))
{
echo "<li>You forget to enter a UserName</li><a href='".$link_Create."'>Start again</a>";
header("Location:PopUp.html");
exit;
}
if(empty($_POST['Password']))
{
echo "<li>You forget to enter a Password</li><a href='".$link_Create."'>Start again</a>";
header("Location:PopUp.html");
exit;
}
if(!preg_match('/^(?=.*\d)(?=.*[A-Za-z])[0-9A-Za-z!##$%]{4,24}$/', $password))
{
echo "<li>Your Password input was wrong, please notice Paswword most be at least 4 characters long, have at least one letter and at least one digit. </li><a href='".$link_Create."'>Start again</a>";
header("Location:PopUp.html");
exit;
}
if(empty($errorMessage)){
$userlist = fopen("login.txt","r");
$success = true;
foreach ($userlist as $user) {
$user_details = explode('|', $user);
if ($user_details[0] == $Username) {
$success = false;
break;
}
}
fclose($userlist);
if ($success==true) {
$writer = fopen("login.txt", "a") or die("Unable to open file.");
fwrite($writer,$Username."|");
fwrite($writer,$password."\n");
fclose($writer);
echo "<br>You have been logged in. <br>";
header("Location:PopUp.html");
exit;
}
else {
echo "<li>This User Name already exist!</li><a href='".$link_Create."'>Start again</a>";
header("Location:PopUp.html");
exit;
}
}
}
?>
Let me know if there is the need of my html code but i don't think it has any effect on the issue.
Thank you very much I appreciate the help.

Answer 1

You have problem with iterating over resource which return fopen function
$userlist = fopen("login.txt","r");
$success = true;
foreach ($userlist as $user) {
$user_details = explode('|', $user);
if ($user_details[0] == $Username) {
$success = false;
break;
}
}
Try to replace it with this iterating over each line of userlist file:
$file = new \SplFileObject("login.txt");
// Loop until we reach the end of the file
while (!$file->eof()) {
$user = $file->fgets();
$user_details = explode('|', $user);
if ($user_details[0] == $Username) {
$success = false;
break;
}
}