08. SessionServiceProvider 详解

[xiaohuilam]

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。