上一篇文章我们说到路由的正则编译，正则编译的目的就是和请求的 url 来匹配，只有匹配上的路由才是我们真正想要的，此外也会通过正则匹配来获取路由的参数。
路由进行正则编译后，就要与请求 request 来进行正则匹配，并且进行一些验证，例如 UriValidator、MethodValidator、SchemeValidator、HostValidator。
class RouteCollection implements Countable, IteratorAggregate
{
public function match(Request $request)
{
$routes = $this->get($request->getMethod());
$route = $this->matchAgainstRoutes($routes, $request);
if (! is_null($route)) {
return $route->bind($request);
}
$others = $this->checkForAlternateVerbs($request);
if (count($others) > 0) {
return $this->getRouteForMethods($request, $others);
}
throw new NotFoundHttpException;
}
protected function matchAgainstRoutes(array $routes, $request, $includingMethod = true)
{
return Arr::first($routes, function ($value) use ($request, $includingMethod) {
return $value->matches($request, $includingMethod);
});
}
}
class Route
{
public function matches(Request $request, $includingMethod = true)
{
$this->compileRoute();
foreach ($this->getValidators() as $validator) {
if (! $includingMethod && $validator instanceof MethodValidator) {
continue;
}
if (! $validator->matches($this, $request)) {
return false;
}
}
return true;
}
public static function getValidators()
{
if (isset(static::$validators)) {
return static::$validators;
}
return static::$validators = [
new UriValidator, new MethodValidator,
new SchemeValidator, new HostValidator,
];
}
}UriValidator 验证主要是目的是查看路由正则与请求是否匹配：
class UriValidator implements ValidatorInterface
{
public function matches(Route $route, Request $request)
{
$path = $request->path() == '/' ? '/' : '/'.$request->path();
return preg_match($route->getCompiled()->getRegex(), rawurldecode($path));
}
}值得注意的是，在匹配路径之前，程序使用了 rawurldecode 来对请求进行解码。
请求方法验证：
class MethodValidator implements ValidatorInterface
{
public function matches(Route $route, Request $request)
{
return in_array($request->getMethod(), $route->methods());
}
}路由 scheme 协议验证：
class SchemeValidator implements ValidatorInterface
{
public function matches(Route $route, Request $request)
{
if ($route->httpOnly()) {
return ! $request->secure();
} elseif ($route->secure()) {
return $request->secure();
}
return true;
}
}
public function httpOnly()
{
return in_array('http', $this->action, true);
}
public function secure()
{
return in_array('https', $this->action, true);
}主域验证：
class HostValidator implements ValidatorInterface
{
public function matches(Route $route, Request $request)
{
if (is_null($route->getCompiled()->getHostRegex())) {
return true;
}
return preg_match($route->getCompiled()->getHostRegex(), $request->getHost());
}
}也就是说，如果路由中并不设置 host 属性，那么这个验证并不进行。
一旦某个路由符合请求的 uri 四项认证，就将会被返回，接下来就要对路由的参数进行绑定与赋值：
class RouteCollection implements Countable, IteratorAggregate
{
public function bind(Request $request)
{
$this->compileRoute();
$this->parameters = (new RouteParameterBinder($this))
->parameters($request);
return $this;
}
}bind 函数负责路由参数与请求 url 的绑定工作:
class RouteParameterBinder
{
public function parameters($request)
{
$parameters = $this->bindPathParameters($request);
if (! is_null($this->route->compiled->getHostRegex())) {
$parameters = $this->bindHostParameters(
$request, $parameters
);
}
return $this->replaceDefaults($parameters);
}
}可以看出，路由参数绑定分为主域参数绑定与路径参数绑定，我们先看路径参数绑定：
class RouteParameterBinder
{
protected function bindPathParameters($request)
{
preg_match($this->route->compiled->getRegex(), '/'.$request->decodedPath(), $matches);
return $this->matchToKeys(array_slice($matches, 1));
}
}例如，{foo}/{baz?}.{ext?} 进行正则编译后结果：
#^/(?P<foo>[^/]++)(?:/(?P<baz>[^/\.]++)(?:\.(?P<ext>[^/]++))?)?$#s其与 request 匹配后的结果为：
$matches = array (
0 = "/foo/baz.ext",
1 = "foo",
foo = "foo",
2 = "baz",
baz = "baz",
3 = "ext",
ext = "ext",
)array_slice($matches, 1) 取出了 $matches 数组 1 之后的结果，然后调用了 matchToKeys 函数，
protected function matchToKeys(array $matches)
{
if (empty($parameterNames = $this->route->parameterNames())) {
return [];
}
$parameters = array_intersect_key($matches, array_flip($parameterNames));
return array_filter($parameters, function ($value) {
return is_string($value) && strlen($value) > 0;
});
}该函数中利用正则获取了路由的所有参数：
class Route
{
public function parameterNames()
{
if (isset($this->parameterNames)) {
return $this->parameterNames;
}
return $this->parameterNames = $this->compileParameterNames();
}
protected function compileParameterNames()
{
preg_match_all('/\{(.*?)\}/', $this->domain().$this->uri, $matches);
return array_map(function ($m) {
return trim($m, '?');
}, $matches[1]);
}
}可以看出，获取路由参数的正则表达式采用了勉强模式，意图提取出所有的路由参数。否则，对于路由 {foo}/{baz?}.{ext?},贪婪型正则表达式 /\{(.*)\}/ 将会匹配整个字符串，而不是各个参数分组。
提取出的参数结果为：
$matches = array (
0 = array (
0 = "{foo}".
1 = "{baz?}",
2 = "{ext?}",
)
1 = array (
0 = "foo".
1 = "baz?",
2 = "ext?",
)
)得出的结果将会去除 $matches[1]，并且将会删除结果中最后的 ?。
之后，在 matchToKeys 函数中，
$parameters = array_intersect_key($matches, array_flip($parameterNames));获取了匹配结果与路由所有参数的交集：
$parameters = array (
foo = "foo",
baz = "baz",
ext = "ext",
)protected function bindHostParameters($request, $parameters)
{
preg_match($this->route->compiled->getHostRegex(), $request->getHost(), $matches);
return array_merge($this->matchToKeys(array_slice($matches, 1)), $parameters);
}步骤与路由参数绑定一致。
进行参数绑定后，有一些可选参数并没有在 request 中匹配到，这时候就要用可选参数的默认值添加到变量 parameters 中：
protected function replaceDefaults(array $parameters)
{
foreach ($parameters as $key => $value) {
$parameters[$key] = isset($value) ? $value : Arr::get($this->route->defaults, $key);
}
foreach ($this->route->defaults as $key => $value) {
if (! isset($parameters[$key])) {
$parameters[$key] = $value;
}
}
return $parameters;
}如果 url 匹配失败，没有找到任何路由与请求相互匹配，就会切换 method 方法，以求任意路由来匹配：
protected function checkForAlternateVerbs($request)
{
$methods = array_diff(Router::$verbs, [$request->getMethod()]);
$others = [];
foreach ($methods as $method) {
if (! is_null($this->matchAgainstRoutes($this->get($method), $request, false))) {
$others[] = $method;
}
}
return $others;
}如果使用其他方法匹配成功，就要判断当前方法是否是 options，如果是则直接返回，否则报出异常：
protected function getRouteForMethods($request, array $methods)
{
if ($request->method() == 'OPTIONS') {
return (new Route('OPTIONS', $request->path(), function () use ($methods) {
return new Response('', 200, ['Allow' => implode(',', $methods)]);
}))->bind($request);
}
$this->methodNotAllowed($methods);
}
protected function methodNotAllowed(array $others)
{
throw new MethodNotAllowedHttpException($others);
}