Laravel 8 Tag

Find N+1 problems instantly by disabling lazy loading

In the next release of Laravel 8, you can strictly disable lazy loading entirely, resulting in an exception:

Preventing lazy loading in development can help you catch N+1 bugs earlier on in the development process. The Laravel ecosystem has various tools to identify N+1 queries. However, this approach brings the issue front-and-center by throwing an exception.

Demo

Let’s walk through this feature real quick by spinning up a development version of the framework 8.x branch since this feature is not out yet at the time of writing. Once released, you will have this feature without switching to the latest 8.x branch.

Setup

First, create a new application:

laravel new strict-lazy-demo

Next, we’ll update the laravel/framework version in composer.json to make sure we have this feature (if you’re trying it out before the next release) by adjusting the version to 8.x-dev:

{
    "require": {
        "laravel/framework": "8.x-dev"
    }
}

Next, run composer update to make sure you get the latest version of the code for this branch:

composer update laravel/framework

At this point, you should set up your preferred database. We like running a local MySQL instance using Laravel’s defaults of using the root user without a password. We find it convenient to use the default .env values locally to get started quickly without any configuration.

mysql -uroot -e"create database strict_lazy_demo"

Once you configure your database of choice, make sure you can migrate:

php artisan migrate:fresh

Demo Data

We’ll create a Post model and define a one-to-many relationship from the User model to demonstrate this feature. We’ll start by creating the Post model and accompanying files:

# Create a model with migration and factory
php artisan make:model -mf Post

First, let’s define our Post migration and factory configuration:

// Your filename will differ based on when you create the file.
// 2021_05_21_000013_create_posts_table.php
Schema::create('posts', function (Blueprint $table) {
    $table->id();
    $table->foreignIdFor(\App\Models\User::class);
    $table->string('title');
    $table->longText('body');
    $table->timestamps();
});

Next, define your PostFactory definition method based on the above schema:

/**
 * Define the model's default state.
 *
 * @return array
 */
public function definition()
{
    return [
        'user_id' => \App\Models\User::factory(),
        'title' => $this->faker->sentence(),
        'body' => implode("\n\n", $this->faker->paragraphs(rand(2,5))),
    ];
}

Finally, open up the DatabaseSeeder file and add the following in the run() method:

/**
 * Seed the application's database.
 *
 * @return void
 */
public function run()
{
    \App\Models\User::factory()
        ->has(\App\Models\Post::factory()->count(3))
        ->create()
    ;
}

Associating Models and Prevent Lazy Loading

Now that we have the migration, seeder, and model created, we are ready to associate a User with the Post model to demo this feature.

Add the following method to the User model to give the user an association with Posts:

// app/Models/User.php
/**
 * @return \Illuminate\Database\Eloquent\Relations\HasMany
 */
public function posts()
{
    return $this->hasMany(Post::class);
}

With that in place, we can migrate and seed the database:

php artisan migrate:fresh --seed

If all went well, we should see something like the following in the console:

Pic courtesy: laravel-news.com

We can now using tinker to inspect our seeded data and relationship:

php artisan tinker
>>> $user = User::first()
=> App\Models\User {#4091
     id: 1,
     name: "Nedra Hayes",
     email: "bruen.marc@example.com",
     email_verified_at: "2021-05-21 00:35:59",
     created_at: "2021-05-21 00:35:59",
     updated_at: "2021-05-21 00:35:59",
   }
>>> $user->posts
=> Illuminate\Database\Eloquent\Collection {#3686
     all: [
       App\Models\Post {#3369
         id: 1,
...

The $user->posts property actually calls the database, thus is “lazy” but is not optimized. The convenience of lazy-loading is nice, but it can come with heavy performance burdens in the long-term.

Disabling Lazy Loading

Now that we have the models set up, we can disable lazy loading across our application. You’d likely want to only disable in non-production environments, which is easy to achieve! Open up the AppServiceProvider class and add the following to the boot() method:

// app/Providers/AppServiceProvider.php
public function boot()
{
    Model::preventLazyLoading(! app()->isProduction());
}

If you run a php artisan tinker session again, this time you should get an exception for a lazy loading violation:

php artisan tinker
>>> $user = \App\Models\User::first()
=> App\Models\User {#3685
     id: 1,
     name: "Nedra Hayes",
     email: "bruen.marc@example.com",
     email_verified_at: "2021-05-21 00:35:59",
     #password: "$2y$10$92IXUNpkjO0rOQ5byMi.Ye4oKoEa3Ro9llC/.og/at2.uheWG/igi",
     #remember_token: "jHSxFGKOdw",
     created_at: "2021-05-21 00:35:59",
     updated_at: "2021-05-21 00:35:59",
   }
>>> $user->posts
Illuminate\Database\LazyLoadingViolationException with message
'Attempted to lazy load [posts] on model [App\Models\User] but lazy loading is disabled.'

If you want to visualize what happens if you use lazy loading in a view file, modify the default route as follows:

Route::get('/', function () {
    return view('welcome', [
        'user' => \App\Models\User::first()
    ]);
});

Next, add the following somewhere in the welcome.blade.php file:

<h2>Posts</h2>
@foreach($user->posts as $post)
    <h3>{{ $post->title }}</h3>
    <p>
        {{ $post->body }}
    </p>
@endforeach

If you load up your application through Valet or artisan serve, you should see something like the following error page:

Pic courtesy: laravel-news.com

Though you’ll get exceptions during development, accidentally deploying code that triggers lazy-loading will continue to work as long as you set environment checking correctly in the service provider.

For more information and to develop web applications using Laravel, Hire Laravel Developer from us as we give you a high-quality product by utilizing all the latest tools and advanced technology. E-mail us any clock at – hello@hkinfosoft.com or Skype us: “hkinfosoft”.

To develop custom web apps using Laravel, please visit our technology page.

Content Source:

1. laravel-news.com

Laravel 8 is just released!

Laravel 8 is now released and includes many new features including Laravel Jetstream, a models directory, model factory classes, migration squashing, rate-limiting improvements, time testing helpers, dynamic blade components, and many more features.

Before we jump into the new features, we’d like to point out that starting with version 6, Laravel now follows semver and will release a new major version every six months. You can see how the release process works here.

Laravel Jetstream

Laravel Jetstream improves upon the existing Laravel UI scaffolding found in previous versions. It provides a starting point for new projects, including login, registration, email verification, two-factor authentication, session management, API support via Laravel, and team management.

Models Directory

Laravel 8’s application skeleton includes an app/Models directory. All generator commands assume models exist in app/Models; however if this directory doesn’t exist, the framework will assume the application keeps models within the app/ folder.

Model Factory Classes

Eloquent model factories are now class-based starting in Laravel 8, with improved support for relationships between factories (i.e., a user has many posts). I think you’ll agree how awesome the new syntax is for generating records via the new and improved model factories:

use App\Models\User;

User::factory()->count(50)->create();

// using a model state "suspended" defined within the factory class
User::factory()->count(5)->suspended()->create();

Migration Squashing

If your application contains many migration files, you can now squash them into a single SQL file. This file will be executed first when running migrations, followed by any remaining migration files that are not part of the squashed schema file. Squashing existing migrations can decrease migration file bloat and possibly improve performance while running tests.

Improved Rate Limiting

Laravel 8 brings improvements to existing rate limiting functionality while supporting backward compatibility with the existing throttle middleware and offering far more flexibility. Laravel 8 has the concept of Rate Limiters that you can define via a facade:

use Illuminate\Cache\RateLimiting\Limit;
use Illuminate\Support\Facades\RateLimiter;

RateLimiter::for('global', function (Request $request) {
    return Limit::perMinute(1000);
});

As you can see, the for() method takes the HTTP request instance, giving you full control over limiting requests dynamically.

Time Testing Helpers

Laravel users have enjoyed full control over time modification via the excellent Carbon PHP library. Laravel 8 brings this one step further by providing convenient test helpers for manipulating the time within tests:

// Travel into the future...
$this->travel(5)->milliseconds();
$this->travel(5)->seconds();
$this->travel(5)->minutes();
$this->travel(5)->hours();
$this->travel(5)->days();
$this->travel(5)->weeks();
$this->travel(5)->years();

// Travel into the past...
$this->travel(-5)->hours();

// Travel to an exact time...
$this->travelTo(now()->subHours(6));

// Return back to the present time...
$this->travelBack();

When using these methods, the time will reset between each test.

Dynamic Blade Components

Sometimes you need to render a blade component dynamically at runtime. Laravel 8 provides the ‘<x-dynamic-component/>’ to render the component:

<x-dynamic-component :component="$componentName" class="mt-4" />

Job Batching

Laravel’s job batching feature allows you to easily execute a batch of jobs and then perform some action when the batch of jobs has completed executing.

The new batch method of the Bus facade may be used to dispatch a batch of jobs. Of course, batching is primarily useful when combined with completion callbacks. So, you may use the then, catch, and finally methods to define completion callbacks for the batch. Each of these callbacks will receive an Illuminate\Bus\Batch instance when they are invoked:

use App\Jobs\ProcessPodcast;
use App\Podcast;
use Illuminate\Bus\Batch;
use Illuminate\Support\Facades\Bus;
use Throwable;

$batch = Bus::batch([
    new ProcessPodcast(Podcast::find(1)),
    new ProcessPodcast(Podcast::find(2)),
    new ProcessPodcast(Podcast::find(3)),
    new ProcessPodcast(Podcast::find(4)),
    new ProcessPodcast(Podcast::find(5)),
])->then(function (Batch $batch) {
    // All jobs completed successfully...
})->catch(function (Batch $batch, Throwable $e) {
    // First batch job failure detected...
})->finally(function (Batch $batch) {
    // The batch has finished executing...
})->dispatch();

return $batch->id;

Improved Maintenance Mode

In previous releases of Laravel, the php artisan down maintenance mode feature may be bypassed using an “allow list” of IP addresses that were allowed to access the application. This feature has been removed in favor of a simpler “secret” / token solution.

While in maintenance mode, you may use the secret option to specify a maintenance mode bypass token:

php artisan down --secret="1630542a-246b-4b66-afa1-dd72a4c43515"

After placing the application in maintenance mode, you may navigate to the application URL matching this token and Laravel will issue a maintenance mode bypass cookie to your browser:

https://example.com/1630542a-246b-4b66-afa1-dd72a4c43515

When accessing this hidden route, you will then be redirected to the / route of the application. Once the cookie has been issued to your browser, you will be able to browse the application normally as if it was not in maintenance mode.

Pre-Rendering The Maintenance Mode View

If you utilize the php artisan down command during deployment, your users may still occasionally encounter errors if they access the application while your Composer dependencies or other infrastructure components are updating. This occurs because a significant part of the Laravel framework must boot in order to determine your application is in maintenance mode and render the maintenance mode view using the templating engine.

For this reason, Laravel now allows you to pre-render a maintenance mode view that will be returned at the very beginning of the request cycle. This view is rendered before any of your application’s dependencies have loaded. You may pre-render a template of your choice using the down command’s render option:

php artisan down --render="errors::503"

For more information and to develop web application using Laravel, Hire Laravel Developer from us as we give you a high-quality product by utilizing all the latest tools and advanced technology. E-mail us any clock at – hello@hkinfosoft.com or Skype us: “hkinfosoft”. To develop custom web apps using React JS, please visit our technology page.

Content Source:

1. laravel-news.com
2. laravel.com