Move attribute names in api to constants

boards/views/api.py

@@ -21,6 +21,8 b" PARAMETER_TAG = 'tag'"
 PARAMETER_OFFSET = 'offset'
 PARAMETER_DIFF_TYPE = 'type'
 PARAMETER_POST = 'post'
+PARAMETER_ADDED = 'added'
+PARAMETER_UPDATED = 'updated'
 
 DIFF_TYPE_HTML = 'html'
 DIFF_TYPE_JSON = 'json'
@@ -46,8 +48,8 b' def api_get_threaddiff(request, thread_i'
                                          timezone.get_current_timezone())
 
     json_data = {
-        'added': [],
-        'updated': [],
+        PARAMETER_ADDED: [],
+        PARAMETER_UPDATED: [],
         'last_update': None,
     }
     added_posts = Post.objects.filter(threads__in=[thread],
@@ -60,9 +62,9 b' def api_get_threaddiff(request, thread_i'
     diff_type = request.GET.get(PARAMETER_DIFF_TYPE, DIFF_TYPE_HTML)
 
     for post in added_posts:
-        json_data['added'].append(get_post_data(post.id, diff_type, request))
+        json_data[PARAMETER_ADDED].append(get_post_data(post.id, diff_type, request))
     for post in updated_posts:
-        json_data['updated'].append(get_post_data(post.id, diff_type, request))
+        json_data[PARAMETER_UPDATED].append(get_post_data(post.id, diff_type, request))
     json_data['last_update'] = datetime_to_epoch(thread.last_edit_time)
 
     return HttpResponse(content=json.dumps(json_data))