大家好，今天給大家介紹下Laravel框架的Pipeline。
它是一個(gè)非常好用的組件，能夠使代碼的結(jié)構(gòu)非常清晰。 Laravel的中間件機(jī)制便是基于它來實(shí)現(xiàn)的。

通過Pipeline，可以輕松實(shí)現(xiàn)APO編程。

官方GIT地址

https://github.com/illuminate/pipeline

下面的代碼是我實(shí)現(xiàn)的一個(gè)簡化版本：

class Pipeline {      /**      * The method to call on each pipe      * @var string      */     protected $method = 'handle';      /**      * The object being passed throw the pipeline      * @var mixed      */     protected $passable;      /**      * The array of class pipes      * @var array      */     protected $pipes = [];      /**      * Set the object being sent through the pipeline      *      * @param $passable      * @return $this      */     public function send($passable)     {         $this->passable = $passable;         return $this;     }      /**      * Set the method to call on the pipes      * @param array $pipes      * @return $this      */     public function through($pipes)     {         $this->pipes = $pipes;         return $this;     }      /**      * @param Closure $destination      * @return mixed      */     public function then(Closure $destination)     {         $pipeline = array_reduce(array_reverse($this->pipes), $this->getSlice(), $destination);         return $pipeline($this->passable);     }       /**      * Get a Closure that represents a slice of the application onion      * @return Closure      */     protected function getSlice()     {         return function($stack, $pipe){             return function ($request) use ($stack, $pipe) {                 return $pipe::{$this->method}($request, $stack);             };         };     }  }

此類主要邏輯就在于then和getSlice方法。通過array_reduce，生成一個(gè)接受一個(gè)參數(shù)的匿名函數(shù)，然后執(zhí)行調(diào)用。

簡單使用示例

class ALogic {     public static function handle($data, Clourse $next)     {         print "開始 A 邏輯";         $ret = $next($data);         print "結(jié)束 A 邏輯";         return $ret;     } }  class BLogic {     public static function handle($data, Clourse $next)     {         print "開始 B 邏輯";         $ret = $next($data);         print "結(jié)束 B 邏輯";         return $ret;     } }  class CLogic {     public static function handle($data, Clourse $next)     {         print "開始 C 邏輯";         $ret = $next($data);         print "結(jié)束 C 邏輯";         return $ret;     } }

$pipes = [     ALogic::class,     BLogic::class,     CLogic::class ];  $data = "any things"; (new Pipeline())->send($data)->through($pipes)->then(function($data){ print $data;});

運(yùn)行結(jié)果：

"開始 A 邏輯" "開始 B 邏輯" "開始 C 邏輯" "any things" "結(jié)束 C 邏輯" "結(jié)束 B 邏輯" "結(jié)束 A 邏輯"

AOP示例

AOP 的優(yōu)點(diǎn)就在于動態(tài)的添加功能，而不對其它層次產(chǎn)生影響，可以非常方便的添加或者刪除功能。

class IpCheck {     public static function handle($data, Clourse $next)     {         if ("IP invalid") { // IP 不合法             throw Exception("ip invalid");         }         return $next($data);     } }  class StatusManage {     public static function handle($data, Clourse $next)     {         // exec 可以執(zhí)行初始化狀態(tài)的操作         $ret = $next($data)         // exec 可以執(zhí)行保存狀態(tài)信息的操作         return $ret;     } }  $pipes = [     IpCheck::class,     StatusManage::class, ];  (new Pipeline())->send($data)->through($pipes)->then(function($data){ "執(zhí)行其它邏輯";});