Obfuscating IDs with Laravel

I saw a pretty common question from Tyris on the Laracast forums this morning about hiding the ID from the URL of their laravel application.

I've done this on a lot of projects, and figured i'd show how i approach the subject using the Hashids library.

Install Hashids:

This part is simple, add it to your project with:

composer require hashids/hashids

Create a provider to handle generating HashIDs automatically for your models.

(Psst...My way of adding event listeners is a little "old-school" now, you might want to upgrade to an observable class, or adding event listeners through the model)

php artisan make:provider HashIdModelProvider

Then make sure you add this to your providers array in config/app.php:

'providers' => [
//
//
//

  \App\Providers\HashIdModelProvider::class
]

Set up a column in your database.

In order to generate a HashId that's unique to the model we're creating it for, we need the model to have an id - these are assigned by the database, so we can only add a HashID after the model has been initially saved.

That means that the column that stores the HashID value will not have a value when saved initially, so it must be nullable(), for example:

Schema::create('posts', function($table) {
    $table->increments('id');
    $table->string('url_string')->nullable(); // So it won't throw errors when saving posts.
    $table->text('post_content');
    $table->timestamps();
});

Listen for the model created event.

When a new post is created, we want to create and save a HashID in the url_string column of the table!

So, add an event listener for the model created event in your service provider you created:

use App\Post;

public function boot()
{
  Post::created(function($model) {
    // Create and save the hashid here.
  });
}

Now, all we have to do is create the actual HashID, assign it to the url_string column of the model, and that's it!

use App\Post;
use Hashids\Hashids;

public function boot()
{
  Post::created(function($model) {
    $generator = new Hashids(Post::class, 10);
    $model->url_string = $generator->encode($model->id);
    $model->save();
  });
}

Notice how in the call to new Hashids, we're passing two arguments:

new Hashids(Post::class, 10);

The first, is a string, which will be something like \App\Post - this acts as a salt of sorts, making sure that the hash it generates is unique to this class.

If you didn't pass this, then the Post with an ID of 1, and a User with an id of 1 may end up with the same hash!

The second argument is a minimum length - by default Hashids will spit out the shortest length string possible - usually one or two characters. We want at least 10 here to make it not look silly in a URL.

(This minimum length stuff is totally optional but i prefer a longer hash by default)

Bonus round!

Do you use route model binding? that is, say you have a route:

use App\Post;

// www.myapp.com/posts/24
Route::get('posts/{post}', function(Post $post) {
  // $post is a fully fledged App\Post instance thanks to model binding!
});

You can update Laravel's automatic resolution for model binding by importing the Route facade and adding this code to your service provider:

use App\Post;
use Hashids\Hashids;
use Illuminate\Support\Facades\Route;

public function boot()
{

// Your other code above here

Route::bind('post', function ($value) {
  return Post::where('url_string', $value)->first();
});

}

Update: Bonus round two:

You can quickly set the column name that route model binding should use to search for by overriding the getRouteKeyName() method on your model:

// Post.php

public function getRouteKeyName()
{
    return 'url_string';
}

Thanks to Lee Willis and Ben Sampson for that one - i didn't know about it! #timesaver

That should be it! If you have any feedback on this article, Tweet me!