About the analysis of PHP pipeline plug-in League\Pipeline

var gulp = require('gulp');
var less = require('gulp-less');
var minifyCSS = require('gulp-csso');
var concat = require('gulp-concat');
var sourcemaps = require('gulp-sourcemaps');

gulp.task('css', function(){
  return gulp.src('client/templates/*.less')
    .pipe(less())
    .pipe(minifyCSS())
    .pipe(gulp.dest('build/css'))
});

gulp.task('js', function(){
  return gulp.src('client/javascript/*.js')
    .pipe(sourcemaps.init())
    .pipe(concat('app.min.js'))
    .pipe(sourcemaps.write())
    .pipe(gulp.dest('build/js'))
});

gulp.task('default', [ 'html', 'css', 'js' ]);

public function demo(Request $request)
{
    $pipe1 = function ($payload, Closure $next) {
        $payload = $payload + 1;
        return $next($payload);
    };

    $pipe2 = function ($payload, Closure $next) {
        $payload = $payload * 3;
        return $next($payload);
    };

    $data = $request->input('data', 0);

    $pipeline = new Pipeline();

    return $pipeline
        ->send($data)
        ->through([$pipe1, $pipe2])
        ->then(function ($data) {
            return $data;
        });
}

composer require league/pipeline

use League\Pipeline\Pipeline;

// 创建两个闭包函数
$pipe1 = function ($payload) {
    return $payload + 1;
};

$pipe2 = function ($payload) {
    return $payload * 3;
};

$route->map(
    'GET',
    '/demo',
    function (ServerRequestInterface $request, ResponseInterface $response
    ) use ($service, $pipe1, $pipe2) {
        $params = $request->getQueryParams();

        // 正常使用
        $pipeline1 = (new Pipeline)
            ->pipe($pipe1)
            ->pipe($pipe2);

        $callback1 = $pipeline1->process($params['data']);

        $response->getBody()->write("<h1 id="正常使用">正常使用</h1>");
        $response->getBody()->write("<p>结果：$callback1</p>");

        // 使用魔术方法
        $pipeline2 = (new Pipeline())
            ->pipe($pipe1)
            ->pipe($pipe2);

        $callback2 = $pipeline2($params['data']);

        $response->getBody()->write("<h1 id="使用魔术方法">使用魔术方法</h1>");
        $response->getBody()->write("<p>结果：$callback2</p>");

        // 使用 Builder
        $builder = new PipelineBuilder();
        $pipeline3 = $builder
            ->add($pipe1)
            ->add($pipe2)
            ->build();

        $callback3 = $pipeline3($params['data']);

        $response->getBody()->write("<h1 id="使用-Builder">使用 Builder</h1>");
        $response->getBody()->write("<p>结果：$callback3</p>");
        return $response;
    }
);

<?php declare(strict_types=1);

namespace League\Pipeline;

interface PipelineInterface extends StageInterface
{
    /**
     * Create a new pipeline with an appended stage.
     *
     * @return static
     */
    public function pipe(callable $operation): PipelineInterface;
}

interface StageInterface
{
    /**
     * Process the payload.
     *
     * @param mixed $payload
     *
     * @return mixed
     */
    public function __invoke($payload);
}

<?php class CallableClass 
{
    function __invoke($x) {
        var_dump($x);
    }
}
$obj = new CallableClass;
$obj(5);
var_dump(is_callable($obj));
?>

int(5)
bool(true)

<?php declare(strict_types=1);

namespace League\Pipeline;

class Pipeline implements PipelineInterface
{
    /**
     * @var callable[]
     */
    private $stages = [];

    /**
     * @var ProcessorInterface
     */
    private $processor;

    public function __construct(ProcessorInterface $processor = null, callable ...$stages)
    {
        $this->processor = $processor ?? new FingersCrossedProcessor;
        $this->stages = $stages;
    }

    public function pipe(callable $stage): PipelineInterface
    {
        $pipeline = clone $this;
        $pipeline->stages[] = $stage;

        return $pipeline;
    }

    public function process($payload)
    {
        return $this->processor->process($payload, ...$this->stages);
    }

    public function __invoke($payload)
    {
        return $this->process($payload);
    }
}

// 按照 $stages 数组顺利，遍历执行管道方法，再将结果传入下一个管道，让「水」一层层「流动」起来
class FingersCrossedProcessor implements ProcessorInterface
{
    public function process($payload, callable ...$stages)
    {
        foreach ($stages as $stage) {
            $payload = $stage($payload);
        }

        return $payload;
    }
}

// 增加一个额外的「过滤网」，经过每个管道后的结果，都需要 check，一旦满足则终止，直接输出结果。
class InterruptibleProcessor implements ProcessorInterface
{
    /**
     * @var callable
     */
    private $check;

    public function __construct(callable $check)
    {
        $this->check = $check;
    }

    public function process($payload, callable ...$stages)
    {
        $check = $this->check;

        foreach ($stages as $stage) {
            $payload = $stage($payload);

            if (true !== $check($payload)) {
                return $payload;
            }
        }

        return $payload;
    }
}

interface ProcessorInterface
{
    /**
     * Process the payload using multiple stages.
     *
     * @param mixed $payload
     *
     * @return mixed
     */
    public function process($payload, callable ...$stages);
}

class PipelineBuilder implements PipelineBuilderInterface
{
    /**
     * @var callable[]
     */
    private $stages = [];

    /**
     * @return self
     */
    public function add(callable $stage): PipelineBuilderInterface
    {
        $this->stages[] = $stage;

        return $this;
    }

    public function build(ProcessorInterface $processor = null): PipelineInterface
    {
        return new Pipeline($processor, ...$this->stages);
    }
}

interface PipelineBuilderInterface
{
    /**
     * Add an stage.
     *
     * @return self
     */
    public function add(callable $stage): PipelineBuilderInterface;

    /**
     * Build a new Pipeline object.
     */
    public function build(ProcessorInterface $processor = null): PipelineInterface;
}