Added permissions_check parameter to generic ItemBuilder

Now check for permissions can be done for generic items in menu. If user
doesn't have permissions for such entry, it won't be displayed for him.

Author: gbdlin

README.rst

@@ -72,7 +72,9 @@ element.
 ``ItemBuilder``
 ***************
 
-Builder that represents simple url. ``name`` argument is required. ``url`` argument is required.
+Builder that represents simple url. ``name`` argument is required. ``url`` argument is required. It also can take
+``permissions_check`` that should be either callable or dotted path to callable that will return True or False
+determining if user can see this option in menu. It should take ``request``, ``context`` and ``menu_name`` parameters.
 
 ``ModelBuilder``
 ****************

admin_toolbox/sidebar/builders/generic.py

@@ -11,18 +11,29 @@ class ItemBuilder(BaseBuilder):
     Simple manual element builder. You have to specify url and name of element. You can specify icon. If icon is not
     provided, will fallback to default one (determined by how much item is nested).
     """
-    def __init__(self, url, name, icon=None, *args, **kwargs):
+    def __init__(self, url, name, icon=None, permissions_check=None, *args, **kwargs):
         super(ItemBuilder, self).__init__(*args, **kwargs)
         self.url = url
         self.name = name
         self.icon = icon
+        if isinstance(permissions_check, string_types):
+            self.permissions_check = import_string(permissions_check)
+        else:
+            self.permissions_check = permissions_check
+
+    def check_permissions(self, request=None, context=None, menu_name='default'):
+        if self.permissions_check is None:
+            return True
+
+        return self.permissions_check(request, context, menu_name)
 
     def build(self, request=None, context=None, menu_name='default'):
-        return {
-            'url': self.url,
-            'name': self.name,
-            'icon': self.icon,
-        }
+        if self.check_permissions(request, context, menu_name):
+            return {
+                'url': self.url,
+                'name': self.name,
+                'icon': self.icon,
+            }
 
 
 class ListBuilder(BaseBuilder):

setup.py

@@ -18,7 +18,7 @@
 setup(
     name='django-admin-toolbox',
 
-    version='1.0.0.dev14',
+    version='1.0.0.dev15',
 
     description='Django admin toolbox - bunch of improvements for default django admin',
     long_description=long_description,