From e246427463ac5edcc6b7115b33838a4367a4f9a9 Mon Sep 17 00:00:00 2001
From: Luke Towers <luke@luketowers.ca>
Date: Wed, 9 Oct 2019 11:51:06 -0600
Subject: [PATCH] Provide system.assets.beforeAddAsset event to modify asset
 attributes

Fixes octobercms/october#4611 (when combined with a PR to https://github.com/heathdutton/cloudflare)
Related: octobercms/october#4092, octobercms/october#3841, octobercms/october#3839
---
 modules/backend/formwidgets/FileUpload.php |  5 +-
 modules/backend/widgets/Form.php           |  5 +-
 modules/system/traits/AssetMaker.php       | 72 +++++++++++++++++-----
 3 files changed, 58 insertions(+), 24 deletions(-)

diff --git a/modules/backend/formwidgets/FileUpload.php b/modules/backend/formwidgets/FileUpload.php
index 0a8f5d1ba..89e2d3e57 100644
--- a/modules/backend/formwidgets/FileUpload.php
+++ b/modules/backend/formwidgets/FileUpload.php
@@ -407,10 +407,7 @@ class FileUpload extends FormWidgetBase
     protected function loadAssets()
     {
         $this->addCss('css/fileupload.css', 'core');
-        $this->addJs('js/fileupload.js', [
-            'build' => 'core',
-            'cache'  => 'false'
-        ]);
+        $this->addJs('js/fileupload.js', 'core');
     }
 
     /**
diff --git a/modules/backend/widgets/Form.php b/modules/backend/widgets/Form.php
index 17e630b96..c16e75bdd 100644
--- a/modules/backend/widgets/Form.php
+++ b/modules/backend/widgets/Form.php
@@ -159,10 +159,7 @@ class Form extends WidgetBase
      */
     protected function loadAssets()
     {
-        $this->addJs('js/october.form.js', [
-            'build' => 'core',
-            'cache'  => 'false'
-        ]);
+        $this->addJs('js/october.form.js', 'core');
     }
 
     /**
diff --git a/modules/system/traits/AssetMaker.php b/modules/system/traits/AssetMaker.php
index 673e53596..4918872e7 100644
--- a/modules/system/traits/AssetMaker.php
+++ b/modules/system/traits/AssetMaker.php
@@ -3,6 +3,7 @@
 use Url;
 use Html;
 use File;
+use Event;
 use System\Models\Parameter;
 use System\Models\PluginVersion;
 use System\Classes\CombineAssets;
@@ -16,7 +17,6 @@ use System\Classes\CombineAssets;
  */
 trait AssetMaker
 {
-
     /**
      * @var array Collection of assets to display in the layout.
      */
@@ -127,16 +127,7 @@ trait AssetMaker
 
         $jsPath = $this->getAssetScheme($jsPath);
 
-        // Prevent CloudFlare's Rocket Loader from breaking stuff
-        // @see octobercms/october#4092, octobercms/october#3841, octobercms/october#3839
-        if (isset($attributes['cache']) && $attributes['cache'] == 'false') {
-            $attributes['data-cfasync'] = 'false';
-            unset($attributes['cache']);
-        }
-
-        if (!in_array($jsPath, $this->assets['js'])) {
-            $this->assets['js'][] = ['path' => $jsPath, 'attributes' => $attributes];
-        }
+        $this->addAsset('js', $jsPath, $attributes);
     }
 
     /**
@@ -164,9 +155,7 @@ trait AssetMaker
 
         $cssPath = $this->getAssetScheme($cssPath);
 
-        if (!in_array($cssPath, $this->assets['css'])) {
-            $this->assets['css'][] = ['path' => $cssPath, 'attributes' => $attributes];
-        }
+        $this->addAsset('css', $cssPath, $attributes);
     }
 
     /**
@@ -190,8 +179,59 @@ trait AssetMaker
 
         $rssPath = $this->getAssetScheme($rssPath);
 
-        if (!in_array($rssPath, $this->assets['rss'])) {
-            $this->assets['rss'][] = ['path' => $rssPath, 'attributes' => $attributes];
+        $this->addAsset('rss', $rssPath, $attributes);
+    }
+
+    /**
+     * Adds the provided asset to the internal asset collections
+     *
+     * @param string $type The type of the asset: 'js' || 'css' || 'rss'
+     * @param string $path The path to the asset
+     * @param array $attributes The attributes for the asset
+     */
+    protected function addAsset(string $type, string $path, array $attributes)
+    {
+        if (!in_array($path, $this->assets[$type])) {
+            /**
+             * @event system.assets.beforeAddAsset
+             * Provides an opportunity to inspect or modify an asset.
+             *
+             * The parameters provided are:
+             * string `$type`: The type of the asset being added
+             * string `$path`: The path to the asset being added
+             * array `$attributes`: The array of attributes for the asset being added.
+             *
+             * All the parameters are provided by reference for modification.
+             * This event is also a halting event, so returning false will prevent the
+             * current asset from being added. Note that duplicates are filtered out
+             * before the event is fired.
+             *
+             * Example usage:
+             *
+             *     Event::listen('system.assets.beforeAddAsset', function (string $type, string $path, array $attributes) {
+             *         if (in_array($path, $blockedAssets)) {
+             *             return false;
+             *         }
+             *     });
+             *
+             * Or
+             *
+             *     $this->bindEvent('assets.beforeAddAsset', function (string $type, string $path, array $attributes) {
+             *         $attributes['special_cdn_flag'] = false;
+             *     });
+             *
+             */
+            if (
+                // Fire local event if exists
+                (
+                    method_exists($this, 'fireEvent') &&
+                    ($this->fireEvent('assets.beforeAddAsset', [&$type, &$path, &$attributes], true) !== false)
+                ) &&
+                // Fire global event
+                (Event::fire('system.assets.beforeAddAsset', [&$type, &$path, &$attributes], true) !== false)
+            ) {
+                $this->assets[$type][] = ['path' => $path, 'attributes' => $attributes];
+            }
         }
     }