Laravel Macro

The following is developed by LaravelThe introductory tutorial column will introduce you to the magical Laravel macro instruction (Macro). I hope it will be helpful to friends in need!

Have you ever wanted a feature in Laravel, but it didn’t really exist? Let me introduce you to Laravel macros. Macros allow you to add custom functionality to Laravel's internal components.

Let us take a simple Request facade method as an example.

Request::macro('introduce', function ($name) {
    echo 'Hello ' . $name . '!';
});
Request::introduce('Caleb'); // outputs "Hello Caleb!"

A more practical Request macro is used to detect the current TLD (top-level domain: .com, .net, .org, .etc...).

Request::macro('tldIs', function ($tld) {
    return Str::is('*.' . $tld, $this->root());
});
Request::tldIs('com') // returns true for app.com
Request::tldIs('dev') // returns false for app.com

You will notice that Laravel automatically binds $this to the context of the Request, rather than in a class that has defined the macro. For example:

class AppServiceProvider
{
    public function boot()
    {
        Request::macro('context', function () {
            return get_class($this);
        }
    }
...
Request::context(); 
// returns 'Illuminate\Http\Request'
// instead of 'App\AppServiceProvider'

Let’s look at a more advanced example. This macro conditionally adds a where statement on the model based on the current TLD.

Builder::macro('whenTldMatches', function($tld, $callback) {
    if (Request::tldIs($tld)) {
        call_user_func($callback->bindTo($this));
    }
    return $this;
});
SomeModel::whenTldMatches('org', function () {
    $this->where('id', '>', 5);
})->get();
// applies ->where() 在 app.org 上应用，而不在 app.com 上应用

Where should we define them?

Service providers are a great place to define macros for your application. App\Providers\AppServiceProvider boot() is I a good injection point, but it gets bloated quickly.

The next step is to create a App\Providers\MacrosServiceProvider and register it in config/app.php. If a macro is relevant, I might create an App\Providers\TldAwareServiceProvider to hold all TLD related macros.

Which components are Macroable?

Macros can be defined on any class with the Macroable attribute. The following is a list of Macroable's facades and classes

Facade

● Cache

● File

● Lang

● Request

● Response

● Route

● URL

Illuminate Classes

● Illuminate\Cache\Repository

● Illuminate\Console\Scheduling\Event

● Illuminate\Database\Eloquent\Builder

● Illuminate\Database\Eloquent\Relation

● Illuminate\Database\Query\Builder

● Illuminate\Filesystem\Filesystem

● Illuminate\Foundation\Testing\TestResponse

● Illuminate\Http\RedirectResponse

● Illuminate\Http\Request

● Illuminate\Http\UploadedFile

● Illuminate\Routing\ResponseFactory

● Illuminate\Routing\Router

● Illuminate\Routing\UrlGenerator

● Illuminate\Support\Arr

● Illuminate\Support\Collection

● Illuminate\Support\Str

● Illuminate\Translation\Translator

● Illuminate\Validation\Rule

Hands-On

If you find yourself duplicating Laravel components throughout your system To perform logic, consider using macros for better expression and reuse. Believe me, very greedy.

Good luck!

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