Improve can extract function.

lib/core/resolvers/UrlResolver.js

@@ -207,7 +207,7 @@ UrlResolver.prototype._extract = function (file, response) {
         mimeType = mimeType.split(';')[0].trim();
     }
 
-    if (!extract.canExtract(mimeType || file)) {
+    if (!extract.canExtract(file, mimeType)) {
         return Q.resolve();
     }
 

lib/util/extract.js

@@ -138,8 +138,16 @@ function moveSingleDirContents(dir) {
 
 // -----------------------------
 
-function canExtract(target) {
-    return !!getExtractor(target);
+function canExtract(src, mimeType) {
+    if (getExtractor(src)) {
+        return true;
+    }
+
+    if (mimeType && getExtractor(mimeType)) {
+        return true;
+    }
+
+    return false;
 }
 
 // Available options: