Django Current

In a previous post , I wrote about a way to keep track of user permissions on a model instance.  For example, I suggested that each model have a permissions subclass that could be instantiated with a user instance passed as a constructor argument.  Methods on that permissions class could then be called to determine if that user has permission to perform various actions. I also suggested that the threadlocals module could then be used to pass in the user instance to the permissions object in the Django template.  However, from various readings, I get the impression that threadlocals may not be the best thing for passing arguments in a template function.   Therefore, I decided to use a more traditional route of creating a template tag to do something similar. I created a template tag that lets you surround a block of HTML code to hide or show the contents based on the return value of the permission function.  The tag below basically says, "if the logged in use...

Sometimes it's nice to be able to add custom code to the save method of objects in the Django Admin.  So, when editing an object on the Admin object detail page (change form), adding the following method override to your ModelAdmin in admin.py will allow you to add custom code to the save function. In admin.py:   class MyModelAdmin(admin.ModelAdmin): def save_model(self, request, obj, form, change): # custom stuff here obj.save() This is documented in the Django Docs , but I found it particularly useful.

I think I've found an interesting way to set up a permissions system in Django.  This system allows you to specify granular permissions on specific object instances and is template friendly. Setup The Permissions Infrastructure First, you create an "abstract" Permissions class that models will use as a permissions base class.  This base permissions class sets up simple caching for the permissions and creates some common methods to be used by all permissions objects.  The current_user represents the logged in that you want to check permissions for a particular object. Notice the use of threadlocals here.  If current_user is not supplied in the constructor, the class will try to lookup the current_user from a variable by the threadlocals middleware (see below).  Be warned, however, some people don't seem to like the threadlocals approach .  To be honest, I'm still trying to evaluate the pluses and minuses, but it sure makes certain things in the templat...