Search for image for every domain level starting from the lowest one. Cache this into memcached

boards/models/attachment/viewers.py

@@ -5,7 +5,7 b' from django.contrib.staticfiles.template'
 from django.core.files.images import get_image_dimensions
 from django.template.defaultfilters import filesizeformat
 
-from boards.utils import get_domain
+from boards.utils import get_domain, cached_result
 
 
 FILE_STUB_IMAGE = 'images/file.png'
@@ -179,11 +179,7 b' class UrlViewer(AbstractViewer):'
         if protocol in URL_PROTOCOLS:
             url_image_name = URL_PROTOCOLS.get(protocol)
         elif domain:
-            filename = 'images/domains/{}.png'.format(domain)
-            if file_exists(filename):
-                url_image_name = 'domains/' + domain
-            else:
-                url_image_name = FILE_STUB_URL
+            url_image_name = self._find_image_for_domains(domain) or FILE_STUB_URL
         else:
             url_image_name = FILE_STUB_URL
 
@@ -195,7 +191,20 b' class UrlViewer(AbstractViewer):'
                '<img class="url-image" src="{}" width="{}" height="{}"/>' \
                '</a>'.format(self.url, image, w, h)
 
+    @cached_result()
+    def _find_image_for_domains(self, domain):
+        """
+        Searches for the domain image for every domain level except top.
+        E.g. for l3.example.co.uk it will search for l3.example.co.uk, then
+        example.co.uk, then co.uk
+        """
+        levels = domain.split('.')
+        while len(levels) > 1:
+            domain = '.'.join(levels)
 
-    def _get_protocol(self):
-        pass
+            filename = 'images/domains/{}.png'.format(domain)
+            if file_exists(filename):
+                return 'domains/' + domain
+            else:
+                del levels[0]
 

boards/utils.py

@@ -34,10 +34,6 b" ANON_IP = '127.0.0.1'"
 
 FILE_EXTENSION_DELIMITER = '.'
 
-KNOWN_DOMAINS = (
-        'org.ru',
-)
-
 
 def is_anonymous_mode():
     return get_bool(SETTING_MESSAGES, SETTING_ANON_MODE)
@@ -157,21 +153,5 b' def get_domain(url: str) -> str:'
     else:
         full_domain = ''
 
-    result = full_domain
-    if full_domain:
-        levels = full_domain.split('.')
-        if len(levels) >= 2:
-            top = levels[-1]
-            second = levels[-2]
+    return full_domain
 
-            has_third_level = len(levels) > 2
-            if has_third_level:
-                third = levels[-3]
-
-            if has_third_level and ('{}.{}'.format(second, top) in KNOWN_DOMAINS):
-                result = '{}.{}.{}'.format(third, second, top)
-            else:
-                result = '{}.{}'.format(second, top)
-
-    return result
-