Allow unique $_GET request only? Generate, verify, forbid values [closed] - php

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Hello everyone again here,
I want to create a PHP script for my software which generates and returns the specific code using one $_GET request with a string and using another verificates this code, then forbid running same string.
Something what should work like this:
1st user's software runs "http://example.com/codes.php?create=" and string like "abc".
and script returns code based on "abc", e.g. "4aO45k", "12sdF4" etc.
2nd user's software runs "http://example.com/codes.php?verify=" and this code.
If this code exists, return true and remove it FOREVER, meaning this code will never be generated again. If this code doesn't exist, return false.
If 1st user's software will run "http://example.com/codes.php?create=abc" another code will be generated.
In simple words:
if $_GET is create, then
generate random alphanumeric string, save it and return
if $_GET is verify, then
check if this string exists, if so, then
return true, remove from saved
otherwise
return false
Possible without databases, SQL, mySQL, FireBird...?
How do I make it using .ini files as storage?
Thanks.

Answer 1

It's possible with files. You can do something like the simple solution below:
A couple of notes:
I don't know what you intend by based on exactly, so this just uses the input as a prefix
This stores every code in a file indefinitely; if used a lot this file will grow very large and checking for the existence of codes, and ensuring new codes are unique can grow very slow
The same code can be verified multiple times, but will never be recreated. Marking them as used after verification is of course possible as well
As a general rule don't go creating global functions and shoving everything in one file like this. It's really just proof of concept of what was asked
<?php
$file = fopen('codes', 'a');
if (!empty($_GET['create'])) {
$seed = $_GET['create'];
do {
$code = uniqid($seed);
} while (codeExists($code));
fwrite($file, $code . "\n");
echo $code;
}
else if (!empty($_GET['verify'])) {
echo codeExists($_GET['verify']) ? 'found' : 'not found';
}
function codeExists($verification) {
$file = fopen('codes', 'r');
$found = false;
while ($code = trim(fgets($file))) {
if ($code == $verification) {
$found = true;
break;
}
}
return $found;
}