Laravel Pipeline Facade

Overview The pipeline pattern is a design strategy that allows you to pass an initial object through a series of discrete stages, or "pipes." Each stage performs a specific operation on the object and then passes it to the next. This matters because it transforms complex, nested logic—like a long chain of `if` statements for database filtering—into a flat, readable array of actions. It promotes the Single Responsibility Principle, ensuring each class does exactly one thing. Prerequisites To get the most out of this tutorial, you should be comfortable with PHP and the Laravel framework. Specifically, you should understand Eloquent query builders, HTTP requests, and the concept of Middlewares, as the pipeline syntax is almost identical to how Laravel handles web requests. Key Libraries & Tools * **Laravel Pipeline Facade**: The core utility used to send an object through a stack of classes. * **Tinkerwell**: A code runner for PHP that allows for quick experimentation with snippets. * **Eloquent Builder**: The object typically being modified in our filtering examples. Code Walkthrough 1. The Basic Closure Pipeline You can start simple by passing a string through closures to sanitize data. ```python use Illuminate\Support\Facades\Pipeline; $result = Pipeline::send(" Hey you :) ") ->through([ function ($content, $next) { return $next(trim($content)); }, function ($content, $next) { return $next(str_replace(":)", " "), $content)); } ]) ->thenReturn(); ``` Here, `send()` sets the initial data, `through()` defines the stages, and `thenReturn()` executes the chain. Each stage must call `$next($content)` to keep the flow moving. 2. Implementation via Dedicated Filter Classes For production apps, moving logic into classes is best practice. Let's create a `SearchFilter` to clean up a controller. ```python class SearchFilter { public function __construct(protected ?string $value) {} public function handle($query, $next) { if (!$this->value) { return $next($query); } $query->whereLike('name', $this->value); return $next($query); } } ``` In your controller, you can now swap messy conditionals for a clean pipeline: ```python $items = Pipeline::send(Item::query()) ->through([ new Filters\SearchFilter($request->search), new Filters\CategoryFilter($request->category), new Filters\BestDealFilter($request->best_deal), ]) ->thenReturn() ->get(); ``` Syntax Notes Laravel pipelines support both `handle()` methods and **invocable classes** (`__invoke`). The signature must always accept the pass-through object and the next closure. Note the use of `thenReturn()`, which is a shorthand for `then(fn($object) => $object)`. Practical Examples Beyond database filtering, pipelines are perfect for **order processing** (validating stock, calculating tax, applying coupons) or **content transformation** (converting Markdown to HTML, then syntax highlighting, then minifying). Tips & Gotchas Always include an **early return** in your filter classes. If a filter value is null and you don't check for it, you might accidentally modify your query in unintended ways. Also, ensure you are importing the `Illuminate\Support\Facades\Pipeline` facade and not the internal routing pipeline, as their signatures can differ slightly.