08. SessionServiceProvider 详解

[Bruce Lam]

前言还没想好。

服务提供者部分

SessionServiceProvider 没有 boot 方法，其 register 方法为

laravel/vendor/laravel/framework/src/Illuminate/Session/SessionServiceProvider.php

Lines 15 to 22 in ca57c28

 public function register() 
 { 
     $this->registerSessionManager(); 
  
     $this->registerSessionDriver(); 
  
     $this->app->singleton(StartSession::class); 
 } 

作用

• 单例注册 Illuminate\Session\SessionManager 为 session

• 单例注册 Illuminate\Session\Store 为 session.store

  具体生成 Illuminate\Session\Store 对象的过程，由你 .env 配置 SESSION_DRIVER 而调用 Illuminate\Session\SessionManager 不同方法：

  • createArrayDriver
  • createCookieDriver
  • createFileDriver
  • createNativeDriver 其实 createFileDriver 就是调用的此方法
  • createDatabaseDriver
  • createApcDriver
  • createMemcachedDriver
  • createRedisDriver

• 单例注册 Illuminate\Session\Middleware\StartSession 中间件

下面，我们以 SESSION_DRIVER=file 继续分析
当 SESSION_DRIVER 为 file 时，会调用到 createFileDriver

laravel/vendor/laravel/framework/src/Illuminate/Session/SessionManager.php

Lines 47 to 50 in ca57c28

 protected function createFileDriver() 
 { 
     return $this->createNativeDriver(); 
 } 

createFileDriver 调用了 createNativeDriver

laravel/vendor/laravel/framework/src/Illuminate/Session/SessionManager.php

Lines 57 to 64 in ca57c28

 protected function createNativeDriver() 
 { 
     $lifetime = $this->app['config']['session.lifetime']; 
  
     return $this->buildSession(new FileSessionHandler( 
         $this->app['files'], $this->app['config']['session.files'], $lifetime 
     )); 
 } 

这里 $this->app['config']['session.files'] 得到的是

laravel/config/session.php

Line 60 in ca57c28

 'files' => storage_path('framework/sessions'), 

然后通过此处实例化 Illuminate\Session\FileSessionHandler

laravel/vendor/laravel/framework/src/Illuminate/Session/SessionManager.php

Line 61 in ca57c28

 return $this->buildSession(new FileSessionHandler( 

然后调用 buildSession 获得 \Illuminate\Session\Store 对象

laravel/vendor/laravel/framework/src/Illuminate/Session/SessionManager.php

Lines 163 to 170 in ca57c28

 protected function buildSession($handler) 
 { 
     if ($this->app['config']['session.encrypt']) { 
         return $this->buildEncryptedSession($handler); 
     } 
  
     return new Store($this->app['config']['session.cookie'], $handler); 
 } 

session 功能 / 操作部分

读取 session

当触发 Session::start 时，

laravel/vendor/laravel/framework/src/Illuminate/Session/Store.php

Lines 69 to 78 in ca57c28

 public function start() 
 { 
     $this->loadSession(); 
  
     if (! $this->has('_token')) { 
         $this->regenerateToken(); 
     } 
  
     return $this->started = true; 
 } 

调用的 loadSession 为

laravel/vendor/laravel/framework/src/Illuminate/Session/Store.php

Lines 85 to 88 in ca57c28

 protected function loadSession() 
 { 
     $this->attributes = array_merge($this->attributes, $this->readFromHandler()); 
 } 

调用的 readFromHandler 为

laravel/vendor/laravel/framework/src/Illuminate/Session/Store.php

Lines 95 to 106 in ca57c28

 protected function readFromHandler() 
 { 
     if ($data = $this->handler->read($this->getId())) { 
         $data = @unserialize($this->prepareForUnserialize($data)); 
  
         if ($data !== false && ! is_null($data) && is_array($data)) { 
             return $data; 
         } 
     } 
  
     return []; 
 } 

这里的 read 方法，就是 FileSessionHandler::read

laravel/vendor/laravel/framework/src/Illuminate/Session/FileSessionHandler.php

Lines 67 to 76 in ca57c28

 public function read($sessionId) 
 { 
     if ($this->files->isFile($path = $this->path.'/'.$sessionId)) { 
         if ($this->files->lastModified($path) >= Carbon::now()->subMinutes($this->minutes)->getTimestamp()) { 
             return $this->files->sharedGet($path); 
         } 
     } 
  
     return ''; 
 } 

执行到这里时， session 中的数据就被存放到了 Illuminate\Session\Store::$attributes 了。

而执行 Session::get 时，

laravel/vendor/laravel/framework/src/Illuminate/Session/Store.php

Lines 205 to 208 in ca57c28

 public function get($key, $default = null) 
 { 
     return Arr::get($this->attributes, $key, $default); 
 } 

正好就能从 Store::$attributes 中取出 session 的数据了。

写入 session

当我们使用 Illuminate\Support\Facades\Session 时，操作是调用到的 session，也就是 Illuminate\Session\SessionManager。但是在 Illuminate\Support\Manager 的 __call 魔术方法，实现了将 session.driver 载入到 session 中被执行的能力。

laravel/vendor/laravel/framework/src/Illuminate/Support/Manager.php

Lines 144 to 147 in ca57c28

 public function __call($method, $parameters) 
 { 
     return $this->driver()->$method(...$parameters); 
 } 

有兴趣的同学请阅读 15. Laravel 神奇的 Manager 类

假如我们执行 Session::put('key', 'value')
会穿透到

laravel/vendor/laravel/framework/src/Illuminate/Session/Store.php

Lines 265 to 274 in ca57c28

 public function put($key, $value = null) 
 { 
     if (! is_array($key)) { 
         $key = [$key => $value]; 
     } 
  
     foreach ($key as $arrayKey => $arrayValue) { 
         Arr::set($this->attributes, $arrayKey, $arrayValue); 
     } 
 } 

当我们手动 Session::save 时，或者程序终止运行触发 register_shutdown_function 时，会触发

laravel/vendor/laravel/framework/src/Illuminate/Session/Store.php

Lines 124 to 133 in ca57c28

 public function save() 
 { 
     $this->ageFlashData(); 
  
     $this->handler->write($this->getId(), $this->prepareForStorage( 
         serialize($this->attributes) 
     )); 
  
     $this->started = false; 
 } 

也就是 FileSessionHandler::write

laravel/vendor/laravel/framework/src/Illuminate/Session/FileSessionHandler.php

Lines 81 to 87 in ca57c28

 public function write($sessionId, $data) 
 { 
     $this->files->put($this->path.'/'.$sessionId, $data, true); 
  
     return true; 
 } 
  

至此，写入 session 的流程走完。