[ui][widgets] Refactor version fingerprinting

This ensure that fingerprint doesn't get encoded as it is
only used to ensure the latest version is served from the cache.

beat/web/ui/widgets.py

@@ -125,6 +125,20 @@ class CodeMirrorJSONEncoder(json.JSONEncoder):
         self.stash = {}
         return encoded
 
+
+class FingerPrintedMedia(forms.Media):
+    """Subclass that adds version fingerprinting to the Media urls
+    """
+
+    def absolute_path(self, path):
+        """Reimplementation to add version fingerprint to ensure file is served
+        for the latest version of the application
+        """
+        abs_path = super(FingerPrintedMedia, self).absolute_path(path)
+        abs_path += '?v={}'.format(__version__)
+        return abs_path
+
+
 class CodeMirrorTextarea(forms.Textarea):
     u"""Textarea widget render with `CodeMirror`
 
@@ -167,13 +181,8 @@ class CodeMirrorTextarea(forms.Textarea):
                 "%s/addon/fold/foldgutter.css" % CODEMIRROR_PATH,
         )
 
-        # adds version fingerprinting to javascript/css files
-        js = ['%s?v=%s' % (k, __version__) for k in js]
-        css = ['%s?v=%s' % (k, __version__) for k in css]
+        return FingerPrintedMedia(css={'all': css}, js=js)
 
-        return forms.Media(css={'all': css},
-                           js=js
-        )
 
     def __init__(
             self, attrs=None, mode=None, theme=None, config=None, size=None,