Cache some of the attachment viewers logic

boards/models/attachment/viewers.py

@@ -87,14 +87,6 b' def get_viewers():'
     return AbstractViewer.__subclasses__()
 
 
-def get_static_dimensions(filename):
-    file_path = finders.find(filename)
-    return get_image_dimensions(file_path)
-
-
-# TODO Move this to utils
-def file_exists(filename):
-    return finders.find(filename) is not None
 
 
 class AbstractViewer:
@@ -128,15 +120,25 b' class AbstractViewer:'
         image_name = PLAIN_FILE_FORMATS.get(self.extension, self.extension)
         file_name = FILE_FILEFORMAT.format(image_name)
 
-        if file_exists(file_name):
+        if self.file_exists(file_name):
             image = file_name
         else:
             image = FILE_STUB_IMAGE
 
-        w, h = get_static_dimensions(image)
+        w, h = self.get_static_dimensions(image)
 
         return ABSTRACT_FORMAT_VIEW.format(self.file.url, static(image), w, h)
 
+    @cached_result()
+    def get_static_dimensions(self, filename):
+        file_path = finders.find(filename)
+        return get_image_dimensions(file_path)
+
+
+    @cached_result()
+    def file_exists(self, filename):
+        return finders.find(filename) is not None
+
 
 class VideoViewer(AbstractViewer):
     @staticmethod
@@ -221,7 +223,7 b' class UrlViewer(AbstractViewer):'
 
         image_path = 'images/{}.png'.format(url_image_name)
         image = static(image_path)
-        w, h = get_static_dimensions(image_path)
+        w, h = self.get_static_dimensions(image_path)
 
         return URL_FORMAT_VIEW.format(self.url, image, w, h)
 
@@ -237,7 +239,7 b' class UrlViewer(AbstractViewer):'
             domain = DOMAIN_DELIMITER.join(levels)
 
             filename = 'images/domains/{}.png'.format(domain)
-            if file_exists(filename):
+            if self.file_exists(filename):
                 return 'domains/' + domain
             else:
                 del levels[0]