[BUGFIX] Correctly set MIME type of .js and .css files

Resolves: #85

Classes/S3Adapter/MultipartUploaderAdapter.php

@@ -26,6 +26,11 @@ class MultipartUploaderAdapter extends AbstractS3Adapter
 {
     const MAX_RETRIES = 10;
 
+    protected static $mimeTypeMap = [
+        'css' => 'text/css',
+        'js'  => 'text/javascript',
+    ];
+
     /**
      * @param string $localFilePath File path and name on local storage
      * @param string $targetFilePath File path and name on target S3 bucket
@@ -34,10 +39,7 @@ class MultipartUploaderAdapter extends AbstractS3Adapter
      */
     public function upload(string $localFilePath, string $targetFilePath, string $bucket, string $cacheControl)
     {
-        $fileInfo = finfo_open(FILEINFO_MIME_TYPE);
-        $contentType = finfo_file($fileInfo, $localFilePath);
-        finfo_close($fileInfo);
-
+        $contentType = $this->detectContentType($localFilePath, $targetFilePath);
         $uploader = new MultipartUploader($this->s3Client, $localFilePath, [
             'bucket' => $bucket,
             'key' => $targetFilePath,
@@ -70,4 +72,31 @@ public function upload(string $localFilePath, string $targetFilePath, string $bu
             throw $e;
         }
     }
+
+    /**
+     * Detect the MIME type with finfo
+     *
+     * Fixes known wrongly detected MIME types.
+     *
+     * @return string|false Detected MIME type, false on failure
+     */
+    private function detectContentType(string $localFilePath, string $targetFilePath)
+    {
+        $fileInfo = finfo_open(FILEINFO_MIME_TYPE);
+        $contentType = finfo_file($fileInfo, $localFilePath);
+        finfo_close($fileInfo);
+
+        if ($contentType === 'text/plain'
+            || $contentType === 'application/octet-stream'
+        ) {
+            // file's magic database often fails to detect plain text files
+            // we manually fix the mime type here.
+            $ext = pathinfo($targetFilePath, PATHINFO_EXTENSION);
+            if (isset(static::$mimeTypeMap[$ext])) {
+                $contentType = static::$mimeTypeMap[$ext];
+            }
+        }
+
+        return $contentType;
+    }
 }