PHP Not correctly reading the file - php

Question

This is my code:
<?php
$pass = $_GET["pass"];
$user = $_GET["user"];
$next = false;
$file = fopen("info.txt", "r") or die("Something went wrong.");
// Output one line until end-of-file
while(!feof($file)) {
if ($next == true and $pass === fgets($file)){
echo "true";
$next = false;
} else {
echo "false" . "<br>";
$next = false;
}
if (fgets($file) == $user) {
$next = true;
}
}
fclose($file);
?>
and this is info.txt
ch1ck3n
kodero1029
note that this is just a made up password
for example, we go to my website containing this code, https://ch1ck3n.com/login/auth/auth.php?user=ch1ck3n&pass=kodero1029
and it prints false TWICE.
I am making a login system using php and a simple txt document.
the php code reads the txt file lines one by one, and if a line matches the username, that means that the password is on the next line. but if you see, go to the website and it will print false twice.
the $next variable is to indicate that the next line is the password.

Answer 1

What's wrong?
Your issue is because:
if (fgets($file) == $user) {
$next = true;
}
Why is this wrong?
This is the only way that $next is true, but you have $user = $_GET["user"] //ch1ck3n but if you View the Manual it states:
fgets:
Returns a string of up to length - 1 bytes read from the file pointed to by handle. If there is no more data to read in the file pointer, then FALSE is returned.
And see also:
Reading ends when length - 1 bytes have been read, or a newline (which is included in the return value)
(my emphesis)
So you're return value from fgets is a string which includes the line ending, and you're comparing this to a text string ch1ck3n without a line ending. Therefore $next will never be true, so for each line of the file, the if/else statement will return the false option.
Solution:
Strip line endings from your strings:
if (trim(fgets($file)) === $user) {
$next = true;
}
The same will need to be done for all occassions you use fgets.
Security Note:
As mentioned in comments, your method of approach for this issue re: security is absolutely the incorrect way of doing things. You should be using POST requsts or Database references or SESSION cookies to safely associate credentials data with the script.
Don't send sensitive information in URL as this is insecure with or without https: Link
Comment by Felippe Duarte

Answer 2

You are reading two lines per iteration of the loop. Since you only have two lines (maybe three?) that means in a single iteration you are done. Do this:
<?php
$pass = $_GET["pass"];
$user = $_GET["user"];
$next = false;
$file = fopen("info.txt", "r") or die("Something went wrong.");
// Output one line until end-of-file
while(!feof($file)) {
$line = rtrim(fgets($file)); //Newline is included in the fgets result
if ($next == true && $pass === $line){
echo "true";
$next = false;
} else {
echo "false" . "<br>";
$next = false;
}
if ($line === $user) {
$next = true;
}
}
fclose($file);
The reason that you get false twice is (probably) because you may have an empty line at the end of the file.