Symfony2 启动流程分析
Symfony2 启动流程分析
入口文件app.php
{{< highlight php >}} <?php
use Symfony\Component\ClassLoader\ApcClassLoader;
use Symfony\Component\HttpFoundation\Request;
$loader = require_once __DIR__.'/../app/bootstrap.php.cache';
// Use APC for autoloading to improve performance.
// Change 'sf2' to a unique prefix in order to prevent cache key conflicts
// with other applications also using APC.
/*
$loader = new ApcClassLoader('sf2', $loader);
$loader->register(true);
*/
require_once __DIR__.'/../app/AppKernel.php';
//require_once __DIR__.'/../app/AppCache.php';
$kernel = new AppKernel('prod', false);
$kernel->loadClassCache();
//$kernel = new AppCache($kernel);
Request::enableHttpMethodParameterOverride();
$request = Request::createFromGlobals();
$response = $kernel->handle($request);
$response->send();
$kernel->terminate($request, $response);
{{< /highlight >}} 入口文件app_dev.php
{{< highlight php >}} <?php
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\Debug\Debug;
// If you don't want to setup permissions the proper way, just uncomment the following PHP line
// read http://symfony.com/doc/current/book/installation.html#configuration-and-setup for more information
//umask(0000);
// This check prevents access to debug front controllers that are deployed by accident to production servers.
// Feel free to remove this, extend it, or make something more sophisticated.
if (isset($_SERVER['HTTP_CLIENT_IP'])
|| isset($_SERVER['HTTP_X_FORWARDED_FOR'])
|| !in_array(@$_SERVER['REMOTE_ADDR'], array('127.0.0.1', 'fe80::1', '::1'))
) {
header('HTTP/1.0 403 Forbidden');
exit('You are not allowed to access this file. Check '.basename(__FILE__).' for more information.');
}
$loader = require_once __DIR__.'/../app/bootstrap.php.cache';
Debug::enable();
require_once __DIR__.'/../app/AppKernel.php';
$kernel = new AppKernel('dev', true);
$kernel->loadClassCache();
Request::enableHttpMethodParameterOverride();
$request = Request::createFromGlobals();
$response = $kernel->handle($request);
$response->send();
$kernel->terminate($request, $response);
{{< /highlight >}} app_dev.php相对于app.php的主要区别在于 environment 与 debug 参数。
app/bootstrap.php.cache：
bootstrap.php.cache 在运行composer update或者composer install 的时候由脚本生成，主要的功能是将Symfony中必须要用到的核心类打包到单个文件中，同时提供classloader。
app/AppKernel.php
扩展自Kernel类，对系统进行配置。创建AppKernel的时候会传入environment 与 debug 参数，environment参数会影响配置文件路径，缓存文件路径，debug参数会影响到缓存文件路径以及系统对cache的处理。
{{< highlight php >}} <?php
use Symfony\Component\HttpKernel\Kernel;
use Symfony\Component\Config\Loader\LoaderInterface;
class AppKernel extends Kernel
{
public function registerBundles()
{
$bundles = array(
new Symfony\Bundle\FrameworkBundle\FrameworkBundle(),
new Symfony\Bundle\SecurityBundle\SecurityBundle(),
new Symfony\Bundle\TwigBundle\TwigBundle(),
new Symfony\Bundle\MonologBundle\MonologBundle(),
new Symfony\Bundle\SwiftmailerBundle\SwiftmailerBundle(),
new Symfony\Bundle\AsseticBundle\AsseticBundle(),
new Doctrine\Bundle\DoctrineBundle\DoctrineBundle(),
new Sensio\Bundle\FrameworkExtraBundle\SensioFrameworkExtraBundle(),
);
if (in_array($this->getEnvironment(), array('dev', 'test'))) {
$bundles[] = new Acme\DemoBundle\AcmeDemoBundle();
$bundles[] = new Symfony\Bundle\WebProfilerBundle\WebProfilerBundle();
$bundles[] = new Sensio\Bundle\DistributionBundle\SensioDistributionBundle();
$bundles[] = new Sensio\Bundle\GeneratorBundle\SensioGeneratorBundle();
}
return $bundles;
}
public function registerContainerConfiguration(LoaderInterface $loader)
{
$loader->load(__DIR__.'/config/config_'.$this->getEnvironment().'.yml');
}
}
{{< /highlight >}} $kernel->loadClassCache();
做一个需要加载cache的标记，但不会进行加载工作。
Request::enableHttpMethodParameterOverride()
是否允许通过发送的参数来修改请求的方法，只对POST有效。
$request = Request::createFromGlobals();
创建request对象，通过获取$_GET,$_POST等数据，创建request对象。
$response = $kernel->handle($request);
处理请求。symfony内核在此处启动。
{{< highlight php >}} public function handle(Request $request, $type = HttpKernelInterface::MASTER_REQUEST, $catch = true) { if (false === $this->booted) { $this->boot(); }
return $this->getHttpKernel()->handle($request, $type, $catch);
}
{{< /highlight >}} boot方法启动内核，进行初始化配置
{{< highlight php >}} public function boot() { if (true === $this->booted) { return; }
if ($this->loadClassCache) {
$this->doLoadClassCache($this->loadClassCache[0], $this->loadClassCache[1]);
}
// init bundles
$this->initializeBundles();
// init container
$this->initializeContainer();
foreach ($this->getBundles() as $bundle) {
$bundle->setContainer($this->container);
$bundle->boot();
}
$this->booted = true;
}
{{< /highlight >}} doLoadClassCache会根据前面loadClassCache的调用，将加载cache目录下的classes.php，如果缓存不存在，则根据classes.map文件来生成。如果debug=true则还会检测每个classes对应原文件的修改时间来判断是否需要重新生成。 初始化bundle，主要是处理bundle的继承关系
{{< highlight php >}} /* * Initializes the data structures related to the bundle management. * * - the bundles property maps a bundle name to the bundle instance, * - the bundleMap property maps a bundle name to the bundle inheritance hierarchy (most derived bundle first). * * @throws \LogicException if two bundles share a common name * @throws \LogicException if a bundle tries to extend a non-registered bundle * @throws \LogicException if a bundle tries to extend itself * @throws \LogicException if two bundles extend the same ancestor / protected function initializeBundles() { // init bundles $this->bundles = array(); $topMostBundles = array(); $directChildren = array();
foreach ($this->registerBundles() as $bundle) {
$name = $bundle->getName();
if (isset($this->bundles[$name])) {
throw new \LogicException(sprintf('Trying to register two bundles with the same name "%s"', $name));
}
$this->bundles[$name] = $bundle;
if ($parentName = $bundle->getParent()) {
if (isset($directChildren[$parentName])) {
throw new \LogicException(sprintf('Bundle "%s" is directly extended by two bundles "%s" and "%s".', $parentName, $name, $directChildren[$parentName]));
}
if ($parentName == $name) {
throw new \LogicException(sprintf('Bundle "%s" can not extend itself.', $name));
}
$directChildren[$parentName] = $name;
} else {
$topMostBundles[$name] = $bundle;
}
}
// look for orphans
if (count($diff = array_values(array_diff(array_keys($directChildren), array_keys($this->bundles))))) {
throw new \LogicException(sprintf('Bundle "%s" extends bundle "%s", which is not registered.', $directChildren[$diff[0]], $diff[0]));
}
// inheritance
$this->bundleMap = array();
foreach ($topMostBundles as $name => $bundle) {
$bundleMap = array($bundle);
$hierarchy = array($name);
while (isset($directChildren[$name])) {
$name = $directChildren[$name];
array_unshift($bundleMap, $this->bundles[$name]);
$hierarchy[] = $name;
}
foreach ($hierarchy as $bundle) {
$this->bundleMap[$bundle] = $bundleMap;
array_pop($bundleMap);
}
}
}
{{< /highlight >}} 初始化container，为symfony的核心，原理与实现方式请参考下面的文章。基本流程为：如果container缓存存在，则直接使用缓存，如果不存在则创建container，获取每个bundle与container相关的信息，加载配置文件，配置每个bundle，打包生成缓存。 Introduction to the Symfony Service Container Dependency Injection
{{< highlight php >}} /* * Initializes the service container. * * The cached version of the service container is used when fresh, otherwise the * container is built. / protected function initializeContainer() { $class = $this->getContainerClass(); $cache = new ConfigCache($this->getCacheDir().'/'.$class.'.php', $this->debug); $fresh = true; if (!$cache->isFresh()) { $container = $this->buildContainer(); $container->compile(); $this->dumpContainer($cache, $container, $class, $this->getContainerBaseClass());
$fresh = false;
}
require_once $cache;
$this->container = new $class();
$this->container->set('kernel', $this);
if (!$fresh && $this->container->has('cache_warmer')) {
$this->container->get('cache_warmer')->warmUp($this->container->getParameter('kernel.cache_dir'));
}
}
{{< /highlight >}} getHttpKernel()->handle()，此时可以通过contianer来获取http_kernel服务对请求进行处理。 $response->send(); 发送内容 $kernel->terminate($request, $response); 结束