laravel session 源码分析

粗略阅读过session 源码  大概有以下几个东西

1.SessonManager  这个laravel  喜欢用的代理类

2.*SessionHandler 各种处理类  

3 .Store类  依赖 各种处理类   也相当于 各种处理类的 代理类  实际操作 还是各种handler 处理类     

示列

Session::get();

1. 首先是门面类  肯定是找到Session门面对应的类  session   然后相当于 make（'session'）其实就是new 的SessionManager类

2.然后就是 调用SessionManager的 get方法  但是这个方法不存在 所以就去寻找 __call方法；一看还真有。下面看下这个方法

    /**
     * Dynamically call the default driver instance.
     *
     * @param  string  $method
     * @param  array  $parameters
     * @return mixed
     */
    public function __call($method, $parameters)
    {
        return $this->driver()->$method(...$parameters);
    }

　　那么driver是什么呢

  /**
     * Get a driver instance.
     *
     * @param  string|null  $driver
     * @return mixed
     *
     * @throws \InvalidArgumentException
     */
    public function driver($driver = null)
    {
        $driver = $driver ?: $this->getDefaultDriver();

        if (is_null($driver)) {
            throw new InvalidArgumentException(sprintf(
                'Unable to resolve NULL driver for [%s].', static::class
            ));
        }

        // If the given driver has not been created before, we will create the instances
        // here and cache it so we can return it next time very quickly. If there is
        // already a driver created by this name, we'll just return that instance.
        if (! isset($this->drivers[$driver])) {
            $this->drivers[$driver] = $this->createDriver($driver);
        }

        return $this->drivers[$driver];
    }

　　下面看看 $this->createDriver($driver)

    /**
     * Create an instance of the "cookie" session driver.
     *
     * @return \Illuminate\Session\Store
     */
    protected function createCookieDriver()
    {
        return $this->buildSession(new CookieSessionHandler(
            $this->container->make('cookie'), $this->config->get('session.lifetime')
        ));
    }

　　再看看看 buildSession

    /**
     * Build the session instance.
     *
     * @param  \SessionHandlerInterface  $handler
     * @return \Illuminate\Session\Store
     */
    protected function buildSession($handler)
    {
        return $this->config->get('session.encrypt')
                ? $this->buildEncryptedSession($handler)
                : new Store($this->config->get('session.cookie'), $handler);
    }

　　最后返回的就是一个Sotre的类

　　那么我们猜 get方法 肯定是Store的方法了. 我们来看看呢

    /**
     * Get an item from the session.
     *
     * @param  string  $key
     * @param  mixed  $default
     * @return mixed
     */
    public function get($key, $default = null)
    {
        return Arr::get($this->attributes, $key, $default);
    }

　　还真的有。。。

最后的疑问 就是  $this->attributes  这个属性是哪里来的呢？  可能我看没读完，，，

 

隔了一会-------------------------找到答案了

通过源码阅读 可以看到 session的启动 是在中间件里面启动的  

    /**
     * Handle an incoming request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Closure  $next
     * @return mixed
     */
    public function handle($request, Closure $next)
    {
        if (! $this->sessionConfigured()) {
            return $next($request);
        }

        $session = $this->getSession($request);

        if ($this->manager->shouldBlock() ||
            ($request->route() && $request->route()->locksFor())) {
            return $this->handleRequestWhileBlocking($request, $session, $next);
        } else {
            return $this->handleStatefulRequest($request, $session, $next);
        }
    }

　　看最后一个方法

    /**
     * Handle the given request within session state.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Illuminate\Contracts\Session\Session  $session
     * @param  \Closure  $next
     * @return mixed
     */
    protected function handleStatefulRequest(Request $request, $session, Closure $next)
    {
        // If a session driver has been configured, we will need to start the session here
        // so that the data is ready for an application. Note that the Laravel sessions
        // do not make use of PHP "native" sessions in any way since they are crappy.
        $request->setLaravelSession(
            $this->startSession($request, $session)
        );

        $this->collectGarbage($session);

        $response = $next($request);

        $this->storeCurrentUrl($request, $session);

        $this->addCookieToResponse($response, $session);

        // Again, if the session has been configured we will need to close out the session
        // so that the attributes may be persisted to some storage medium. We will also
        // add the session identifier cookie to the application response headers now.
        $this->saveSession($request);

        return $response;
    }

　　然后 通过  $this->startSession($request, $session)

    /**
     * Start the session for the given request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  \Illuminate\Contracts\Session\Session  $session
     * @return \Illuminate\Contracts\Session\Session
     */
    protected function startSession(Request $request, $session)
    {
        return tap($session, function ($session) use ($request) {
            $session->setRequestOnHandler($request);

            $session->start();
        });
    }

　　看到没  最后一句  start函数

    /**
     * Start the session, reading the data from a handler.
     *
     * @return bool
     */
    public function start()
    {
        $this->loadSession();

        if (! $this->has('_token')) {
            $this->regenerateToken();
        }

        return $this->started = true;
    }

　　接着追

    /**
     * Load the session data from the handler.
     *
     * @return void
     */
    protected function loadSession()
    {
        $this->attributes = array_merge($this->attributes, $this->readFromHandler());
    }

　　看到没 终于知道attribute属性 是哪里来的了。