Bundle unminified JS; minify via ClosureCompilerService when in production

Falls back to a less effective minification library if ClosureCompilerService errors or is unavailable. Minification takes a while (20 seconds or so), but it only happens when assets are modified. Still, this means enabling/disabling extensions is taking far too long. Possible solutions:

- Don't minify initially; set a process running in the background to do minification, and server unminified assets in the meantime.
- Refactor compiler to send each JS file to CCS individually, only if that particular file has been modified.

flarum/gulp has also been updated to no longer support uglification.

closes #582

src/Asset/JsCompiler.php

@@ -10,10 +10,29 @@
 
 namespace Flarum\Asset;
 
-use Flarum\Asset\RevisionCompiler;
+use Exception;
+use MatthiasMullie\Minify;
+use s9e\TextFormatter\Configurator\JavaScript\Minifiers\ClosureCompilerService;
 
 class JsCompiler extends RevisionCompiler
 {
+    /**
+     * @var bool
+     */
+    protected $minify;
+
+    /**
+     * @param string $path
+     * @param string $filename
+     * @param bool $minify
+     */
+    public function __construct($path, $filename, $minify = false)
+    {
+        parent::__construct($path, $filename);
+
+        $this->minify = $minify;
+    }
+
     /**
      * {@inheritdoc}
      */
@@ -21,4 +40,59 @@ class JsCompiler extends RevisionCompiler
     {
         return $string.";\n";
     }
+
+    /**
+     * @inheritDoc
+     */
+    public function compile()
+    {
+        $output = parent::compile();
+
+        if ($this->minify) {
+            set_time_limit(60);
+
+            try {
+                $output = $this->minifyWithClosureCompilerService($output);
+            } catch (Exception $e) {
+                $output = $this->minifyWithFallback($output);
+            }
+        }
+
+        return $output;
+    }
+
+    /**
+     * @inheritDoc
+     */
+    protected function getCacheDifferentiator()
+    {
+        return $this->minify;
+    }
+
+    /**
+     * @param string $source
+     * @return string
+     */
+    protected function minifyWithClosureCompilerService($source)
+    {
+        $minifier = new ClosureCompilerService;
+
+        $minifier->compilationLevel = 'SIMPLE_OPTIMIZATIONS';
+        $minifier->timeout = 60;
+
+        $output = $minifier->minify($source);
+
+        return $output;
+    }
+
+    /**
+     * @param string $source
+     * @return string
+     */
+    protected function minifyWithFallback($source)
+    {
+        $minifier = new Minify\JS($source);
+
+        return $minifier->minify();
+    }
 }

src/Asset/LessCompiler.php

@@ -10,9 +10,8 @@
 
 namespace Flarum\Asset;
 
-use Flarum\Asset\RevisionCompiler;
-use Less_Parser;
 use Less_Exception_Parser;
+use Less_Parser;
 
 class LessCompiler extends RevisionCompiler
 {

src/Asset/RevisionCompiler.php

@@ -10,7 +10,6 @@
 
 namespace Flarum\Asset;
 
-use Flarum\Asset\CompilerInterface;
 use Illuminate\Support\Str;
 
 class RevisionCompiler implements CompilerInterface
@@ -64,30 +63,41 @@ class RevisionCompiler implements CompilerInterface
      */
     public function getFile()
     {
-        $revision = $this->getRevision();
+        $old = $this->getRevision();
 
         $lastModTime = 0;
         foreach ($this->files as $file) {
             $lastModTime = max($lastModTime, filemtime($file));
         }
 
-        $ext = pathinfo($this->filename, PATHINFO_EXTENSION);
-        $file = $this->path.'/'.substr_replace($this->filename, '-'.$revision, -strlen($ext) - 1, 0);
+        $current = hash('crc32b', serialize([$lastModTime, $this->getCacheDifferentiator()]));
 
-        if (! ($exists = file_exists($file)) || filemtime($file) < $lastModTime) {
+        $ext = pathinfo($this->filename, PATHINFO_EXTENSION);
+        $file = $this->path.'/'.substr_replace($this->filename, '-'.$old, -strlen($ext) - 1, 0);
+
+        $exists = file_exists($file);
+
+        if (! $exists || $old !== $current) {
             if ($exists) {
                 unlink($file);
             }
 
-            $revision = Str::quickRandom();
-            $this->putRevision($revision);
-            $file = $this->path.'/'.substr_replace($this->filename, '-'.$revision, -strlen($ext) - 1, 0);
+            $this->putRevision($current);
+            $file = $this->path.'/'.substr_replace($this->filename, '-'.$current, -strlen($ext) - 1, 0);
             file_put_contents($file, $this->compile());
         }
 
         return $file;
     }
 
+    /**
+     * @return mixed
+     */
+    protected function getCacheDifferentiator()
+    {
+        return null;
+    }
+
     /**
      * @param string $string
      * @return string