Laravel is a popular and widely used open-source PHP framework. It follows the MVC architectural pattern and provides many essential features for developing web applications, such as routing, caching, and authentication. Besides the basic features, it offers many advanced features, including the Laravel Pipeline.
Laravel pipeline is a powerful concept that is used to handle sequential data processing. It provides a convenient and flexible way to manipulate data by passing it through several stages. Each pipeline modifies the data by applying a specific operation to it. Everyday use cases of Laravel’s pipeline are the implementation of data transformation, middleware request handling, validation, and authorization tasks.
Writing a pipeline provides several benefits instead of writing the logic in the controller for each data manipulation task. These perks include but are not limited to the following:
Modularity: The pipeline allows us to break down complex data processing tasks into miniature, modular stages. Each stage can focus on a specific task, making the overall process more manageable and easier to maintain.
Reusability: We can make our code more reusable by reusing a single pipeline for another task, which enforces the DRY (don't repeat yourself) principle.
Flexibility: We can easily add, remove, or rearrange stages in the pipeline to adjust the workflow according to our requirements. This flexibility makes adapting the data processing logic easier as the application evolves.
Cleaner code: Using pipelines, we can write cleaner and more expressive code that reflects the data flow through the processing pipeline. This can make the codebase easier to understand and maintain and improve readability.
To define a pipeline, we create a class in the application that consists of a handle
method. The core logic of that pipeline goes into that method. We can create a class anywhere in the project, depending on how we split different application modules. Here, we will define the pipeline classes in the app/Pipeline
directory.
Consider cleaning a sentence by removing the extra white spaces and stop-words and then converting it into a title case. Let us break this task into the following sub-tasks:
Removing extra white spaces
Removing stop words
Converting to the title case
We will create the following classes for each sub-tasks respectively:
RemoveExtraSpaces
RemoveStopWords
ToTitleCase
By breaking our code into different stages, we enforce separation of concerns in our application. Separation of concerns in programming means breaking down an extensive program into smaller parts, with each part doing its job without interfering too much with what the other parts are doing.
We will create a separate pipeline for each sub-task. To demonstrate the step-by-step cleaning process, let us create a variable with a sentence as a value that needs cleaning. We will then pass that sentence through each pipeline as illustrated below:
<?php namespace App\Pipelines; class RemoveExtraSpaces { public function handle($sentence, $next) { $cleanedSentence = preg_replace('/\s+/', ' ', trim($sentence)); return $next($cleanedSentence); } }
We can change the data flow passing to different pipelines by rearranging the classes using the through
method.
Here is a line-by-line explanation of all the files above:
app/Pipelines/RemoveExtraSpaces.php
Line 7–8: Removing extra white spaces from the sentence using regular expressions and passing the cleaned sentence to the next pipeline.
app/Pipelines/RemoveStopWords.php
Line 5: Creating an array to store the stop words.
Line 8–10: Removing the stop words from the sentence.
Line 11: Passing the cleaned sentence to the next pipeline.
app/Pipelines/ToTitleCase.php
Line 7–8: Converting the sentence to the title case and passing the cleaned sentence to the next pipeline.
routes/web.php
Line 5: Creating a variable with a sentence we want to clean.
Line 7: Resolving the instance of the Pipeline class by utilizing Laravel’s service container.
Line 8: Sending the value of $sentence
to the pipeline.
Line 9–13: Specifying the sequence of pipeline stages the data will go through.
Line 14: Execute the pipeline and return the result.
As the code example above shows, the Laravel pipeline consists of several key components that work together to process data through several stages. These components include:
Pipeline class: This is the central component of Laravel's pipeline feature. It provides methods for sending data through the pipeline and defining the pipeline flow by specifying the stages the data should pass through.
Stages: The pipeline stages are the individual steps or actions that the data goes through as it passes through the pipeline. Each stage represents a class that implements a handle
method, which receives the data, processes it, and passes it on to the next stage.
Data: The actual data that is processed by the pipeline. It could be a string, an array, an object, a collection, or even a media file. The data is sent through the pipeline using the send
method of the Pipeline
class.
Closure: A method that can be passed around as a variable and invoked later. The closures represent the next stage in the pipeline. Each pipeline stage receives a closure as an argument, which can invoke to pass the data on to the next stage.
Containers: Laravel's service container resolves the pipeline and its stages from the application's service container. This lets us define and manage pipeline stages using Laravel's built-in dependency injection system.
Laravel pipelines are a powerful feature used to streamline complex tasks. However, using pipelines can also introduce some performance overhead. Each stage in the pipeline adds some level of processing time and memory consumption. Therefore, it is crucial not to use them for every task. We should make direct calls to the appropriate methods for simple tasks.
Laravel pipelines provide a robust way to implement and manage data processing in the application. Using pipelines, we can split the complicated tasks into easy-to-use and smaller chunks, making our code more readable and easy to maintain. Furthermore, the ability of pipelines to encapsulate sequential tasks within a single structure simplifies reusability, which helps reduce redundancy.