PHP, generate string with format, check against SQL db? [closed] - php

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I'm trying to use PHP as a way to process this in a webpage, my typical language is java so i am unfamiliar with how this would be done for product keys.
This is basically the process:
1. Generate random string with format XX-XXXX-XXXX-XXX a mix of numbers and letters.
2. Check if it already exists in an SQL database
3. If exists, generate another one and repeat?
So how would I do this using PHP?
Please explain what i would need to do and what is the best way of going about it.

Answer 1

Generate random string from following function.
<?php
function randomString() {
$alphabet = "abcdefghijklmnopqrstuwxyzABCDEFGHIJKLMNOPQRSTUWXYZ0123456789";
$pass = array(); //remember to declare $pass as an array
$alphaLength = strlen($alphabet) - 1; //put the length -1 in cache
$array_lengths = array(2,4,4,3);
foreach($array_lengths as $v){
for ($i = 0; $i < $v; $i++) {
$n = rand(0, $alphaLength);
$pass[] = $alphabet[$n];
}
$pass[] = '-';
}
return rtrim(implode($pass),'-'); //turn the array into a string
}
echo randomString();
?>
SQL
Please create unique key field and use ON DUPLICATE KEY query for insert/ update data
DEMO

Answer 2

You can generates randomnumbers key using this way.
echo rk(2)."-".rk(4)."-".rk(4)."-".rk(3);
function rk($chars) {
$letters = 'abcefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890';
return substr(str_shuffle($letters), 0, $chars);
}

Answer 3

Here's a process that could be of use!
<?php
/** The function below was taken from http://stackoverflow.com/questions/853813/how-to-create-a-random-string-using-php **/
function randString($length, $charset='ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'){
$str = '';
$count = strlen($charset);
while ($length--) {
$str .= $charset[mt_rand(0, $count-1)];
}
return $str;
}
/** The function that will do your work is: **/
function theProcess(){
/** Now to inefficiently concatenate your random string together. **/
$theString = randString(2)."-".randString(4)."-".randString(4)."-".randString(3);
echo $theString;
/** Proceed to query your database using MySQLi or PDO, with a query similar to: **/
/** Add your preliminary (connection) code here. **/
$sthandler = $dbhandler->prepare('SELECT 1 FROM products WHERE productKey = ?');
$sthandler->execute(array($theString));
/** Check whether a result is returned from MySQL. **/
if ($sthandler->rowCount() > 0) {
exit("IT EXISTS!");
} else {
theProcess();
}
}
/** Call the function the first time. **/
theProcess();
?>