CODEWITHSUNDEEP
php
Ankit Balyan
Ankit Balyan

Reputation: 1329

Generating set of random unique codes in php

I'm trying to generate a set of unique Alpha Numeric code in php. I tried using anonymous function and closures.
Here when I generate more than 1000 codes, there are changes of codes getting duplicate. So I tried to generate a new code if any duplicate found.
Below is my code which isn't working as expected, I'm getting "still DUPLICATE Exist" a few times and its not regenerating code even a single time. 

$start = 0;
$count = 10;
$codes = [];
$another = $this;
for ($i=$start; $i < $count; $i++) {
    $getUniqueCode = function (&$codes) use ($another, &$getUniqueCode) {
        $newCode = $another->genRandomCode();
        if (in_array($newCode, $codes)) {
            echo "Regenerate on DUPLICATE FOUND - $newCode <br/>";
            return $getUniqueCode($codes);
        } else {
            return $newCode;
        }
    };
    $newCode = $getUniqueCode($codes);
    if (\in_array($newCode, $codes)) {
        echo "still DUPLICATE Exist - $newCode <br/>";
    }

    array_push($codes, $newCode);
}


private function genRandomCode()
{
    $str = "ABCDEFGHIGKLMNOPQRSTUVWXYZ0123456789";
    $randInt = rand(1000000, 9999999);
    $randString = "";
    for ($i=0; $i < 6; $i++) {
        $randRem = $randInt % 36;
        $randInt = $randInt / 36;
        $randString .= $str[$randRem];
    }
    return $randString;
}

Upvotes: 1

Views: 162

Answers (1)

Timothy Groote
Timothy Groote

Reputation: 8643

Your original code recurses, but i don't think you need to do that.

$start = 0;
$count = 10;
$codes = [];
$another = $this;
for ($i=$start; $i < $count; $i++) {
    //do not pass $codes as a reference here
    $getUniqueCode = function ($codes) use ($another) 
    {
        $newCode = $another->genRandomCode();
        while(in_array($newCode, $codes))
        {
            echo "Regenerate on DUPLICATE FOUND - $newCode <br/>";
        }

        return $newCode;
    };

    $newCode = $getUniqueCode($codes);
    if (\in_array($newCode, $codes)) {
        echo "still DUPLICATE Exist - $newCode <br/>";
    }

    array_push($codes, $newCode);
}

Arguably however, a better way to handle a coupon system like this is to generate the possible coupon codes beforehand, store them in a database, and select one at random for activation. this guarantees a unique code, and lets you keep track of which codes you have used so far.

Upvotes: 1

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