代码研磨 Slim v3 (一)--app->get()&route->add()
index.php代码如下：
$app->get('/forbase', function ($request, $response, $args){
Example\Module\Base::instance()->init($request,$response);
return $response;
})->add(Example\MiddleWare\MyMiddleware::instance(Example\Module\Base::instance()));
APP->get()代码如下：
/**
* Add GET route
*
* @param string $pattern The route URI pattern
* @param mixed $callable The route callback routine
*
* @return \Slim\Interfaces\RouteInterface
*/
public function get($pattern, $callable)
{
return $this->map(['GET'], $pattern, $callable);
}
APP->map()代码如下：
/**
* Add route with multiple methods
*
* @param string[] $methods Numeric array of HTTP method names
* @param string $pattern The route URI pattern
* @param mixed $callable The route callback routine
*
* @return RouteInterface
*/
public function map(array $methods, $pattern, $callable)
{
if ($callable instanceof Closure) {
$callable = $callable->bindTo($this->container);
}
$route = $this->container->get('router')->map($methods, $pattern, $callable);
if (is_callable([$route, 'setContainer'])) {
$route->setContainer($this->container);
}
if (is_callable([$route, 'setOutputBuffering'])) {
$route->setOutputBuffering($this->container->get('settings')['outputBuffering']);
}
return $route;
}
执行完这个map方法后，这个route就被创建了。
$callable = $callable->bindTo($this->container);
用来将$this->container绑定到$callable中，这样$callable就可以访问container里的数据，but我没找到怎么用。这是遗留问题之一。
$route = $this->container->get('router')->map($methods, $pattern, $callable);
做了两件事：
1.获取router；
2.router调用map().
看看Slim\Container类：
class Container extends PimpleContainer implements ContainerInterface
{
/**
* Finds an entry of the container by its identifier and returns it.
*
* @param string $id Identifier of the entry to look for.
*
* @throws ContainerValueNotFoundException No entry was found for this identifier.
* @throws ContainerException Error while retrieving the entry.
*
* @return mixed Entry.
*/
public function get($id)
{
if (!$this->offsetExists($id)) {
throw new ContainerValueNotFoundException(sprintf('Identifier "%s" is not defined.', $id));
}
return $this->offsetGet($id);
}
}
get()会调用$this->offsetGet()，这个方法在Pimple\Container里。
看看PimpleContainer类：
class Container implements \ArrayAccess
{
public function offsetGet($id)
{
if (!isset($this->keys[$id])) {
throw new \InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $id));
}
if (
isset($this->raw[$id])
|| !is_object($this->values[$id])
|| isset($this->protected[$this->values[$id]])
|| !method_exists($this->values[$id], '__invoke')
) {
return $this->values[$id];
}
if (isset($this->factories[$this->values[$id]])) {
return $this->values[$id]($this);
}
$raw = $this->values[$id];
$val = $this->values[$id] = $raw($this);
$this->raw[$id] = $raw;
$this->frozen[$id] = true;
return $val;
}
}
这个类实现了\ArrayAccess接口，官方的解释是说呢，使得访问对象像访问对象那样，即obj['name']拿到name属性。其实能够像访问数组那样访问对象的原因在于ArrayAccess这个接口里的所有方法，在obj['name']就是访问了obj的offsetGet()方法。可以自己覆写这个方法，实现数据存入哪里已经从哪里取出。
这两句话也比较有意思：$raw = $this->values[$id];$val = $this->values[$id] = $raw($this); 一开始没搞懂$raw($this)是干什么的，因为经过上一步的$this->values[$id]其实就已经拿到Closure了，应该很应当的想到是Closure的参数。没有搞明白的原因在于我认为这一步就已经执行Closure了。我错了，$raw($this)这里才执行了闭包函数。是不是可以总结为只有Closure被调用了才执行，而调用应该来自 “=“的右侧。
map()用来创建新的route并添加到router中。
public function map($methods, $pattern, $handler)
{
if (!is_string($pattern)) {
throw new InvalidArgumentException('Route pattern must be a string');
}
// Prepend parent group pattern(s)
if ($this->routeGroups) {
$pattern = $this->processGroups() . $pattern;
}
// According to RFC methods are defined in uppercase (See RFC 7231)
$methods = array_map("strtoupper", $methods);
// Add route
$route = new Route($methods, $pattern, $handler, $this->routeGroups, $this->routeCounter);
$this->routes[$route->getIdentifier()] = $route;
$this->routeCounter++;
return $route;
}
$methods = array_map("strtoupper", $methods); 调用了库函数array_map，用途就是将$methods作为参数出传入'strtoupper'中。
new Route($methods, $pattern, $handler, $this->routeGroups, $this->routeCounter); 创建了新的route。
/**
* Route
*/
class Route extends Routable implements RouteInterface
{
public function __construct($methods, $pattern, $callable, $groups = [], $identifier = 0)
{
$this->methods = $methods;
$this->pattern = $pattern;
$this->callable = $callable;
$this->groups = $groups;
$this->identifier = 'route' . $identifier;
}
}
router中还给route标识了identify，其实就是'routeXX'的样式。
$route->setContainer($this->container);
$route->setOutputBuffering($this->container->get('settings')['outputBuffering']);为新添加的route设置container和outputBuffering。
最后，app->get()会返回一个route。
route add Middleware代码即index.php 中->add();
route->add()方法其实是使用Routable这个抽象类的。
/**
* A routable, middleware-aware object
*
* @package Slim
* @since 3.0.0
*/
abstract class Routable
{
/**
* Prepend middleware to the middleware collection
*
* @param mixed $callable The callback routine
*
* @return static
*/
public function add($callable)
{
$callable = $this->resolveCallable($callable);
if ($callable instanceof Closure) {
$callable = $callable->bindTo($this->container);
}
$this->middleware[] = $callable;
return $this;
}
}
在add里还是做了一个绑定，让闭包函数可以访问$this->container。接着将Closure装入到middleware[]数组中，在这个closure也就是route middleware run的时候就会将middleware数组中的元素加入到Middleware stack中。通过CallMiddlewareStack来依次执行Middleware。
至此，APP成功添加了一个route，并且给这个route添加了一个middleware。
