A better pattern for ajax loading with pyramid?

Question

I've read up on using different renderers or overriding renderer but I'm wondering if there's a better way to handle this pattern.

Right now, in my view I'm returning a set of items to the template:

@view_config(
    route_name = 'name',
    permission = 'perm',
    renderer   = 'r.mako'
)
def r( request ):
     items = get_items()
     return { 'items': items }

Now I want the ajax version to just renderer a subset of it, also with some data. My current working code:

@view_config(
    route_name = 'name',
    permission = 'perm',
    renderer   = 'r.mako'
)
def r( request ):
     items = get_items()

     if ajax:
         return Response( to_json( {
                             'data1':  1,
                             'data2':  2,
                             'data3':  3,
                             'html':  renderers.render( 'shortr.mako',
                                                        { 'items': items },
                                                        request )
                         } )

     return { 'items': items }

I guess specifically I wonder if there's a cleaner way to override the renderer and then wrap it in something, without explicitly calling render and making sure I got the dict right or request as a param. thanks

Answer 1

I would suggest using 2 views which properly allow you to apply a different "look-and-feel" (responses) to the same data.

def get_items(request):
    return {} # values that you can pick and choose from in each view

@view_config(route_name='name', permission='perm', xhr=True, renderer='json')
def r_ajax(request):
    items = get_items(request)
    return {
        'data1': 1, 'data2': 2, 'data3': 3,
        'html': renderers.render('shortr.mako', {'items': items}, request),
    }

@view_config(route_name='name', permission='perm', renderer='r.mako')
def r_html(request):
    items = get_items(request)
    return items

If you're afraid of repeating things for the view configuration, Pyramid 1.3 comes with a cool new feature on its class-based views:

@view_defaults(route_name='name', permission='perm')
class R(object):
    def __init__(self, request):
        self.request = request
        self.items = # ...

    @view_config(xhr=True, renderer='json')
    def ajax(request):
        return {
            'data1': 1, 'data2': 2, 'data3': 3,
            'html': renderers.render('shortr.mako', {'items': items}, request),
        }

    @view_config(renderer='r.mako')
    def html(request):
        return self.items