laravel-slug.php

<?php

namespace App\Services;

use App\Post;

class Slug
{
    /**
     * @param $title
     * @param int $id
     * @return string
     * @throws \Exception
     */
    public function createSlug($title, $id = 0)
    {
        // Normalize the title
        $slug = str_slug($title);

        // Get any that could possibly be related.
        // This cuts the queries down by doing it once.
        $allSlugs = $this->getRelatedSlugs($slug, $id);

        // If we haven't used it before then we are all good.
        if (! $allSlugs->contains('slug', $slug)){
            return $slug;
        }

        // Just append numbers like a savage until we find not used.
        for ($i = 1; $i <= 10; $i++) {
            $newSlug = $slug.'-'.$i;
            if (! $allSlugs->contains('slug', $newSlug)) {
                return $newSlug;
            }
        }

        throw new \Exception('Can not create a unique slug');
    }

    protected function getRelatedSlugs($slug, $id = 0)
    {
        return Post::select('slug')->where('slug', 'like', $slug.'%')
            ->where('id', '<>', $id)
            ->get();
    }
}

Usage:

use App\Helpers\CoolSlug;
$slugLibrary = new CoolSlug(\App\Post::class);
return $slugLibrary->createSlug('test');

CoolSlug Class:

<?php
namespace App\Helpers;

class CoolSlug {
    private $entity;

    /**
     * Instantiate a new CoolSlug instance.
     */
    public function __construct($entity) {
        $this->entity = $entity;
    }
    
    /**
     * Generate a URL friendly "slug" from the given string.
     * 
     * @param $title String
     * @return string
     * @throws \Exception
     */
    public function createSlug($title) {
        // Normalize the title
        $slug = \Illuminate\Support\Str::slug($title, '-');

        // Get any that could possibly be related.
        // This cuts the queries down by doing it once.
        $allSlugs = $this->getRelatedSlugs($slug);

        // If we haven't used it before then we are all good.
        if($allSlugs == 0) {
            return $slug;
        }

        // Just append numbers like a savage until we find not used.
        for($i = 1; $i <= 20; $i++) {
            $newSlug = $slug. '-'. $i;
            if($this->getRelatedSlugs($newSlug) == 0) {
                return $newSlug;
            }
        }

        throw new \Exception('Can not create a unique slug.');
    }

    protected function getRelatedSlugs($slug) {
        return call_user_func(array($this->entity, 'select'), 'permalink')->where('permalink', $slug)->count();
    }
}