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Using Traversal in Pyramid Views

A trivial example of how to use traversal in your view code.

You may remember that a Pyramid view is called with a context argument:

def my_view(context, request):
    return render_view_to_response(context, request)

When using traversal, context will be the resource object that was found by traversal. Configuring which resources a view responds to can be done easily via either the @view.config decorator...

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from models import MyResource

@view_config(context=MyResource)
def my_view(context, request):
    return render_view_to_response(context, request)

or via config.add_view:

from models import MyResource
config = Configurator()
config.add_view('myapp.views.my_view', context=MyResource)

Either way, any request that triggers traversal and traverses to a MyResource instance will result in calling this view with that instance as the context argument.

Optional: Using Interfaces

If your resource classes implement interfaces, you can configure your views by interface. This is one way to decouple view code from a specific resource implementation:

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# models.py
from zope.interface import implements
from zope.interface import Interface

class IMyResource(Interface):
    pass

class MyResource(object):
    implements(IMyResource)

# views.py
from models import IMyResource

@view_config(context=IMyResource)
def my_view(context, request):
    return render_view_to_response(context, request)

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