Frontend refactor (#1471)

Refactor Frontend + Asset code

- Use Laravel's Filesystem component for asset IO, meaning theoretically
  assets should be storable on S3 etc.

- More reliable checking for asset recompilation when debug mode is on,
  so you don't have to constantly delete the compiled assets to force
  a recompile. Should also fix issues with locale JS files being
  recompiled with the same name and cached.

- Remove JavaScript minification, because it will be done by Webpack
  (exception is for the TextFormatter JS).

- Add support for JS sourcemaps.

- Separate frontend view and assets completely. This is an important
  distinction because frontend assets are compiled independent of a
  request, whereas putting together a view depends on a request.

- Bind frontend view/asset factory instances to the container (in
  service providers) rather than subclassing. Asset and content
  populators can be added to these factories – these are simply objects
  that populate the asset compilers or the view with information.

- Add RouteHandlerFactory functions that make it easy to hook up a
  frontend controller with a frontend instance ± some content.

- Remove the need for "nojs"

- Fix cache:clear command

- Recompile assets when settings/enabled extensions change

src/Http/ControllerRouteHandler.php

@@ -25,13 +25,13 @@ class ControllerRouteHandler
     protected $container;
 
     /**
-     * @var string
+     * @var string|callable
      */
     protected $controller;
 
     /**
      * @param Container $container
-     * @param string $controller
+     * @param string|callable $controller
      */
     public function __construct(Container $container, $controller)
     {
@@ -54,12 +54,16 @@ class ControllerRouteHandler
     }
 
     /**
-     * @param string $class
+     * @param string|callable $class
      * @return RequestHandlerInterface
      */
     protected function resolveController($class)
     {
-        $controller = $this->container->make($class);
+        if (is_callable($class)) {
+            $controller = $this->container->call($class);
+        } else {
+            $controller = $this->container->make($class);
+        }
 
         if (! ($controller instanceof RequestHandlerInterface)) {
             throw new InvalidArgumentException(

src/Http/Middleware/SetLocale.php

@@ -46,6 +46,8 @@ class SetLocale implements Middleware
             $this->locales->setLocale($locale);
         }
 
+        $request = $request->withAttribute('locale', $this->locales->getLocale());
+
         return $handler->handle($request);
     }
 }

src/Http/RouteHandlerFactory.php

@@ -11,6 +11,7 @@
 
 namespace Flarum\Http;
 
+use Flarum\Frontend\Controller as FrontendController;
 use Illuminate\Contracts\Container\Container;
 
 class RouteHandlerFactory
@@ -29,11 +30,47 @@ class RouteHandlerFactory
     }
 
     /**
-     * @param string $controller
+     * @param string|callable $controller
      * @return ControllerRouteHandler
      */
     public function toController($controller)
     {
         return new ControllerRouteHandler($this->container, $controller);
     }
+
+    /**
+     * @param string $frontend
+     * @param string|null $content
+     * @return ControllerRouteHandler
+     */
+    public function toFrontend(string $frontend, string $content = null)
+    {
+        return $this->toController(function (Container $container) use ($frontend, $content) {
+            $frontend = $container->make($frontend);
+
+            if ($content) {
+                $frontend->add($container->make($content));
+            }
+
+            return new FrontendController($frontend);
+        });
+    }
+
+    /**
+     * @param string|null $content
+     * @return ControllerRouteHandler
+     */
+    public function toForum(string $content = null)
+    {
+        return $this->toFrontend('flarum.forum.frontend', $content);
+    }
+
+    /**
+     * @param string|null $content
+     * @return ControllerRouteHandler
+     */
+    public function toAdmin(string $content = null)
+    {
+        return $this->toFrontend('flarum.admin.frontend', $content);
+    }
 }