php微框架 flight源码阅读——3.路由Router实现及执行过程
现在来分析路由实现及执行过程，在项目目录下创建index.php，使用文档中的路由例子（含有路由规则匹配），如下：
<?php
require 'flight/Flight.php';
Flight::route('/@name/@id:[0-9]{3}', function($name, $id){
echo "hello, $name ($id)!";
});
Flight::start();首先引入'flight/Flight.php'框架入口文件，在执行Flight::route()时当然在Flight类中找不到该方法，于是就会调用下面的__callStatic()魔术方法，然后去执行\flight\core\Dispatcher::invokeMethod(array($app, $name), $params)，其中$app就是之前框架初始化好后的Engine类实例化对象，$params就是定义路由传入的参数：匹配规则或url和一个匿名回调函数。
/**
* Handles calls to static methods.
*
* @param string $name Method name
* @param array $params Method parameters
* @return mixed Callback results
* @throws \Exception
*/
public static function __callStatic($name, $params) {
$app = Flight::app();
return \flight\core\Dispatcher::invokeMethod(array($app, $name), $params);
}接着会调用Dispatcher类的invokeMethod()方法，$class和$method分别对应刚才的$app对象和$name参数。is_object($class)返回true，很明显count($params)值为2，因此会执行case语句中的$class->$method($params[0], $params[1])，就是去Engine对象中调用route()方法。
/**
* Invokes a method.
*
* @param mixed $func Class method
* @param array $params Class method parameters
* @return mixed Function results
*/
public static function invokeMethod($func, array &$params = array()) {
list($class, $method) = $func;
$instance = is_object($class);
switch (count($params)) {
case 0:
return ($instance) ?
$class->$method() :
$class::$method();
case 1:
return ($instance) ?
$class->$method($params[0]) :
$class::$method($params[0]);
case 2:
return ($instance) ?
$class->$method($params[0], $params[1]) :
$class::$method($params[0], $params[1]);
case 3:
return ($instance) ?
$class->$method($params[0], $params[1], $params[2]) :
$class::$method($params[0], $params[1], $params[2]);
case 4:
return ($instance) ?
$class->$method($params[0], $params[1], $params[2], $params[3]) :
$class::$method($params[0], $params[1], $params[2], $params[3]);
case 5:
return ($instance) ?
$class->$method($params[0], $params[1], $params[2], $params[3], $params[4]) :
$class::$method($params[0], $params[1], $params[2], $params[3], $params[4]);
default:
return call_user_func_array($func, $params);
}
}当然在Engine对象中也没有route()方法，于是会触发当前对象中的__call()魔术方法。在这个方法中通过$this->dispatcher->get($name)去获取框架初始化时设置的Dispatcher对象的$events属性：$this->dispatcher->set($name, array($this, '_'.$name))，然后$events属性数组中会有一个route键名对应的值为[$this Engine对象, '_route']数组，返回的$callback=[$this Engine对象, '_route']并且is_callable($callback)==true。
/**
* Handles calls to class methods.
*
* @param string $name Method name
* @param array $params Method parameters
* @return mixed Callback results
* @throws \Exception
*/
public function __call($name, $params) {
$callback = $this->dispatcher->get($name);
if (is_callable($callback)) {
return $this->dispatcher->run($name, $params);
}
if (!$this->loader->get($name)) {
throw new \Exception("{$name} must be a mapped method.");
}
$shared = (!empty($params)) ? (bool)$params[0] : true;
return $this->loader->load($name, $shared);
}那么，接着就该执行$this->dispatcher->run($name, $params)，那就看下Dispatcher对象中的run()方法，由于框架初始化时没有对route()方法进行设置前置和后置操作，所以直接执行$this->execute($this->get($name), $params)。
/**
* Dispatches an event.
*
* @param string $name Event name
* @param array $params Callback parameters
* @return string Output of callback
* @throws \Exception
*/
public function run($name, array $params = array()) {
$output = '';
// Run pre-filters
if (!empty($this->filters[$name]['before'])) {
$this->filter($this->filters[$name]['before'], $params, $output);
}
// Run requested method
$output = $this->execute($this->get($name), $params);
// Run post-filters
if (!empty($this->filters[$name]['after'])) {
$this->filter($this->filters[$name]['after'], $params, $output);
}
return $output;
}接着来看Dispatcher对象中的execute方法，因为is_callable($callback)==true && is_array($callback)，所以又再次调用self::invokeMethod($callback, $params)。
/**
* Executes a callback function.
*
* @param callback $callback Callback function
* @param array $params Function parameters
* @return mixed Function results
* @throws \Exception
*/
public static function execute($callback, array &$params = array()) {
if (is_callable($callback)) {
return is_array($callback) ?
self::invokeMethod($callback, $params) :
self::callFunction($callback, $params);
}
else {
throw new \Exception('Invalid callback specified.');
}
}但是这次调用invokeMethod方法跟刚才有所不同，刚才的$callback是[$app, 'route']，现在的$callback是[$this Engine对象, '_route']，$params是一样的。然后invokeMethod方法中的$class为$this Engine对象，$method为'_route'，is_object($class)为true。然后再执行$class->$method($params[0], $params[1])，这次在Engine对象中就可以调用到_route方法了。
接着来看Engine对象的_route()方法做了什么。$this->router()会触发当前对象的__call()魔术方法，根据刚才的分析$this->dispatcher->get($name)返回null。而$this->loader->get($name)返回true，然后就去执行$this->loader->load($name, $shared)。在Load对象的load方法中isset($this->classes[$name])为true，isset($this->instances[$name])返回false，在框架初始化时设置的$params和$backcall都为默认值，所以会执行$this->newInstance($class, $params)，在newInstance方法中直接return new $class()。总结：$this->router()其实就是通过工厂模式去实例化框架初始化时所设置的'\flight\net\Router'类，依次论推$this->request()、$this->response()、$this->view()是一样的逻辑。
flight/Engine.php
/**
* Routes a URL to a callback function.
*
* @param string $pattern URL pattern to match
* @param callback $callback Callback function
* @param boolean $pass_route Pass the matching route object to the callback
*/
public function _route($pattern, $callback, $pass_route = false) {
$this->router()->map($pattern, $callback, $pass_route);
}flight/core/Loader.php
/**
* Loads a registered class.
*
* @param string $name Method name
* @param bool $shared Shared instance
* @return object Class instance
* @throws \Exception
*/
public function load($name, $shared = true) {
$obj = null;
if (isset($this->classes[$name])) {
list($class, $params, $callback) = $this->classes[$name];
$exists = isset($this->instances[$name]);
if ($shared) {
$obj = ($exists) ?
$this->getInstance($name) :
$this->newInstance($class, $params);
if (!$exists) {
$this->instances[$name] = $obj;
}
}
else {
$obj = $this->newInstance($class, $params);
}
if ($callback && (!$shared || !$exists)) {
$ref = array(&$obj);
call_user_func_array($callback, $ref);
}
}
return $obj;
}
/**
* Gets a new instance of a class.
*
* @param string|callable $class Class name or callback function to instantiate class
* @param array $params Class initialization parameters
* @return object Class instance
* @throws \Exception
*/
public function newInstance($class, array $params = array()) {
if (is_callable($class)) {
return call_user_func_array($class, $params);
}
switch (count($params)) {
case 0:
return new $class();
case 1:
return new $class($params[0]);
case 2:
return new $class($params[0], $params[1]);
case 3:
return new $class($params[0], $params[1], $params[2]);
case 4:
return new $class($params[0], $params[1], $params[2], $params[3]);
case 5:
return new $class($params[0], $params[1], $params[2], $params[3], $params[4]);
default:
try {
$refClass = new \ReflectionClass($class);
return $refClass->newInstanceArgs($params);
} catch (\ReflectionException $e) {
throw new \Exception("Cannot instantiate {$class}", 0, $e);
}
}
}那$this->router()->map($pattern, $callback, $pass_route)操作的目的就是将用户定义的一个或多个route压入到Router对象的$routes属性索引数组中。至此，index.php中的Flight::route()操作就结束了，整个操作流程目的就是获取并解析用户定义的所有route，存储到Router对象的$routes属性索引数组中。接下来的Flight::start()，顾名思义，就是拿着处理好的路由请求信息去真正干活了。
flight/net/Router.php
/**
* Maps a URL pattern to a callback function.
*
* @param string $pattern URL pattern to match
* @param callback $callback Callback function
* @param boolean $pass_route Pass the matching route object to the callback
*/
public function map($pattern, $callback, $pass_route = false) {
$url = $pattern;
$methods = array('*');
//通过用户route定义的匹配规则，解析定义的methods，如'GET|POST /'
if (strpos($pattern, ' ') !== false) {
list($method, $url) = explode(' ', trim($pattern), 2);
$methods = explode('|', $method);
}
$this->routes[] = new Route($url, $callback, $methods, $pass_route);
}Flight::start()要做的工作就是通过Request对象中获取的真实请求信息与用户所定义的路由进行匹配验证，匹配通过的然后通过Response对象返回给用户请求的结果。
根据刚才的分析，start()方法也会去调用Dispatcher类的invokeMethod方法，但$params是null，所以会执行$class->$method()，通过刚才的分析，会调用Engine对象__call()魔术方法的$this->dispatcher->run($name, $params)。在dispatcher对象的run()方法中，由于start()方法在框架初始化时设置有前置操作，所以在这里会执行所设置的前置操作，最后会执行Engine对象的_start()方法。
这里重点要分析的是从$route = $router->route($request)开始的操作。在实例化Request类获取$request对象时，会做些初始化操作，会将实际的请求信息设置在属性中，用于和用户定义的route进行匹配。
/**
* Starts the framework.
* @throws \Exception
*/
public function _start() {
$dispatched = false;
$self = $this;
$request = $this->request(); //获取Request对象
$response = $this->response(); //获取Response对象
$router = $this->router(); //获取Router对象
// Allow filters to run 设置start()方法执行的后置操作
$this->after('start', function() use ($self) {
$self->stop();
});
// Flush any existing output
if (ob_get_length() > 0) {
$response->write(ob_get_clean());
}
// Enable output buffering
ob_start();
// Route the request
while ($route = $router->route($request)) {
$params = array_values($route->params);
// Add route info to the parameter list
if ($route->pass) {
$params[] = $route;
}
// Call route handler
$continue = $this->dispatcher->execute(
$route->callback,
$params
);
$dispatched = true;
if (!$continue) break;
$router->next();
$dispatched = false;
}
if (!$dispatched) {
$this->notFound();
}
}flight/net/Request.php
/**
* Constructor.
*
* @param array $config Request configuration
*/
public function __construct($config = array()) {
// Default properties
if (empty($config)) {
$config = array(
'url' => str_replace('@', '%40', self::getVar('REQUEST_URI', '/')),
'base' => str_replace(array('\\',' '), array('/','%20'), dirname(self::getVar('SCRIPT_NAME'))),
'method' => self::getMethod(),
'referrer' => self::getVar('HTTP_REFERER'),
'ip' => self::getVar('REMOTE_ADDR'),
'ajax' => self::getVar('HTTP_X_REQUESTED_WITH') == 'XMLHttpRequest',
'scheme' => self::getVar('SERVER_PROTOCOL', 'HTTP/1.1'),
'user_agent' => self::getVar('HTTP_USER_AGENT'),
'type' => self::getVar('CONTENT_TYPE'),
'length' => self::getVar('CONTENT_LENGTH', 0),
'query' => new Collection($_GET),
'data' => new Collection($_POST),
'cookies' => new Collection($_COOKIE),
'files' => new Collection($_FILES),
'secure' => self::getVar('HTTPS', 'off') != 'off',
'accept' => self::getVar('HTTP_ACCEPT'),
'proxy_ip' => self::getProxyIpAddress()
);
}
$this->init($config);
}现在来看$router->route($request) 操作都做了什么。$route = $this->current()可以获取到刚才$this->router->map()保存的用户定义的第一个route，如果为false，就会直接返回404。否则，通过$route->matchMethod($request->method) && $route->matchUrl($request->url, $this->case_sensitive)来匹配验证用户定义的routes和实际请求的信息（请求方法和请求url）。
flight/net/Router.php
/**
* Routes the current request.
*
* @param Request $request Request object
* @return Route|bool Matching route or false if no match
*/
public function route(Request $request) {
while ($route = $this->current()) {
if ($route !== false && $route->matchMethod($request->method) && $route->matchUrl($request->url, $this->case_sensitive)) {
return $route;
}
$this->next();
}
return false;
}flight/net/Route.php
/**
* Checks if a URL matches the route pattern. Also parses named parameters in the URL.
*
* @param string $url Requested URL
* @param boolean $case_sensitive Case sensitive matching
* @return boolean Match status
*/
public function matchUrl($url, $case_sensitive = false) {
// Wildcard or exact match
if ($this->pattern === '*' || $this->pattern === $url) {
return true;
}
$ids = array();
$last_char = substr($this->pattern, -1);
// Get splat
if ($last_char === '*') {
$n = 0;
$len = strlen($url);
$count = substr_count($this->pattern, '/');
for ($i = 0; $i < $len; $i++) {
if ($url[$i] == '/') $n++;
if ($n == $count) break;
}
$this->splat = (string)substr($url, $i+1); // /blog/* *匹配的部分
}
// Build the regex for matching
$regex = str_replace(array(')','/*'), array(')?','(/?|/.*?)'), $this->pattern);
//对路由匹配实现正则匹配 "/@name/@id:[0-9]{3}"
$regex = preg_replace_callback(
'#@([\w]+)(:([^/\(\)]*))?#',
function($matches) use (&$ids) {
$ids[$matches[1]] = null;
if (isset($matches[3])) {
return '(?P<'.$matches[1].'>'.$matches[3].')';
}
return '(?P<'.$matches[1].'>[^/\?]+)';
},
$regex
);
// Fix trailing slash
if ($last_char === '/') {
$regex .= '?';
}
// Allow trailing slash
else {
$regex .= '/?';
}
// Attempt to match route and named parameters
if (preg_match('#^'.$regex.'(?:\?.*)?$#'.(($case_sensitive) ? '' : 'i'), $url, $matches)) {
foreach ($ids as $k => $v) {
$this->params[$k] = (array_key_exists($k, $matches)) ? urldecode($matches[$k]) : null;
}
$this->regex = $regex;
return true;
}
return false;
}
/**
* Checks if an HTTP method matches the route methods.
*
* @param string $method HTTP method
* @return bool Match status
*/
public function matchMethod($method) {
return count(array_intersect(array($method, '*'), $this->methods)) > 0;
}php微框架 flight源码阅读系列