ShortIds.php

<?php namespace Cleanse\Urls\Classes;

use ApplicationException;

class ShortIds
{
    public $radix;
    public $words;

    public function __construct()
    {
        $numbers = range(0, 9);
        $letters = range('a', 'z');
        $special = ['$', '-', '_', '+', '!', '*', '(', ')', ','];

        $this->radix = array_merge($numbers, $letters, $special);

        $filename = './plugins/cleanse/urls/assets/csv/words.csv';

        if (file_exists($filename)) {
            $this->words = array_map('str_getcsv', file($filename));
        } else {
            throw new ApplicationException('Cannot find .csv file.');
        }

    }

    public function newShorty($model, $max_len = 8)
    {
        $max = pow(count($this->radix), $max_len);

        do {
            $id = rand(1, $max);
            $newId = $this->radixToString($id);

            $exists = $model::where('id', '=', $newId)->first();
        } while (!in_array($id, $this->words) && $exists);

        return $newId;
    }

    public function radixToString($value)
    {
        $base = count($this->radix);

        if ($base < 2) {
            throw new ApplicationException('radix must have at least two digits.');
        }

        $i = intval($value);
        $out = [];
        while ($i > 0) {
            $i = floor($i/$base);

            $remainder = $i % $base;
            $out[] = $this->radix[$remainder];
        }

        return implode('', $out);
    }
}