support language switcher for post detail view, add navigation modifier to select current category in the menu when in post detail view

djangocms_blog/menu.py

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 from cms.menu_bases import CMSAttachMenu
-from menus.base import NavigationNode
+from menus.base import Modifier, NavigationNode
 from menus.menu_pool import menu_pool
 from django.db.models.signals import post_save, post_delete
 from django.utils.translation import ugettext_lazy as _, get_language
@@ -28,6 +28,30 @@ class BlogCategoryMenu(CMSAttachMenu):
 menu_pool.register_menu(BlogCategoryMenu)
 
 
+class BlogNavModifier(Modifier):
+    """
+    This navigation modifier makes sure that when 
+    a particular blog post is viewed, 
+    a corresponding category is selected in menu
+    """
+    def modify(self, request, nodes, namespace, root_id, post_cut, breadcrumb):
+        if not post_cut: return nodes
+        if not hasattr(request, 'toolbar'):
+            return nodes
+        if request.toolbar.get_object_model() != 'djangocms_blog.post':
+            return nodes
+        cat = request.toolbar.obj.categories.first()
+        if not cat: return nodes
+
+        for node in nodes:
+            if (node.namespace == BlogCategoryMenu.__name__ and
+                    cat.pk == node.id):
+                node.selected = True
+                break
+        return nodes
+
+menu_pool.register_modifier(BlogNavModifier)
+
 def clear_menu_cache(**kwargs):
     menu_pool.clear(all=True)