Changes between Version 5 and Version 6 of TemplatePitfalls

Timestamp:

Sep 6, 2005, 7:23:52 AM (19 years ago)

Author:

garthk

Comment:

Atonement for previous crummy advice

TemplatePitfalls

@@ -25 +25 @@
 }}}
 
-== Context variables and template inheritance ==
+== custom context variables for generic views ==
 
-It's handy to define a method each view can call to fill in its {{{Context}}} with the right variables. If you're inheriting templates, you should also do the same with the method. I've ended up with an {{{app_vars}}} method in each app's views module which calls {{{site_vars}}} in the site. 
+More advanced versions of the base template (mine is {{{base.html}}}, following the model set in the administration interface) might need a consistent set of context variables generated on the fly based on the identity of the current user, what they're doing, what's happening elsewhere on the site, and so on. 
 
-{{{site_vars}}} goes in {{{sitename/views/sitename.py}}} if you're trying to match the default shape of the application namespace, or in {{{sitename/views.py}}} if you're flattening it: 
+If you're using generic views, though, there's no obvious way to make these context variables available. 
 
-{{{
-def site_vars(request, **kwargs): 
-    """Determine context variables for the site's base template."""
-    user = request.user
-    is_anonymous = user.is_anonymous()
-    if is_anonymous: 
-        username = name = '(anonymous)'
-    else: 
-        username = user.username
-        name = user.get_full_name()
-        if not name: 
-            name = username
-    vars = {
-        'is_anonymous': is_anonymous,
-        'name': name,
-        'username': username,
-    }
-    vars.update(kwargs)
-    return vars
-}}}
+The solution is to use [http://www.djangoproject.com/documentation/templates_python/#writing-custom-template-tags custom template tags], which can modify a page's context variables on the fly. 
 
-A custom version of {{{app_vars}}} goes in each {{{sitename/apps/appname/views/appname.py}}} (or, if you're flattening the namespace, {{{sitename/apps/appname/views.py}}}):
+If your needs are middling simple, or you don't want to have to write your own custom template tag from scratch, I've developed a generic option: [http://www.deadlybloodyserious.com/categories/django/2005/09/06.html vars],  which defines a fairly generic {{{pushvars}}} tag that calls the function of your choice and pushes its results into the current context. 
 
-{{{
-def app_vars(request, **kwargs): 
-    """Determine context variables for the application and site base templates."""
-    vars = {} # set your app variables here
-    vars.update(site_vars(request, **kwargs))
-    return vars
-}}}
+I'm posting this to atone for my previous crummy advice on this Wiki page. 
 
-The keyword arguments let you define additional useful variables for your page without having to further manipulate the dictionary: just keep piling on the arguments to {{{app_vars}}}. Let's say your base template likes to have a {{{title}}} variable available to it: 
-
-{{{
-def index(request): 
-    """View the appname index."""
-
-    # Customise the app variables the hard way
-    vars = app_vars(request)
-    vars['title'] = "Index" 
-
-    # Or, the easy way
-    vars = app_vars(request, title="Index")
-
-    # Load the template, construct the context, and render one against the other: 
-    t = template_loader.get_template('appname_index')
-    c = Context(request, vars)
-    return HttpResponse(t.render(c))
-}}}
+{{{- garthk}}}