12. VIEW CONFIGURATION
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from pyramid.response import Response |
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def hello_world(request): |
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return Response(’hello!’) |
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# config is assumed to be an instance of the |
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# pyramid.config.Configurator class |
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config.add_view(hello_world, route_name=’hello’) |
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The first argument, view, is required. It must either be a Python object which is the view itself or a dotted Python name to such an object. In the above example, view is the hello_world function. All other arguments are optional. See pyramid.config.Configurator.add_view() for more information.
When you use only add_view() to add view configurations, you don’t need to issue a scan in order for the view configuration to take effect.
12.2 @view_defaults Class Decorator
latex-note.png
This feature is new in Pyramid 1.3.
If you use a class as a view, you can use the pyramid.view.view_defaults class decorator on the class to provide defaults to the view configuration information used by every @view_config decorator that decorates a method of that class.
For instance, if you’ve got a class that has methods that represent “REST actions”, all which are mapped to the same route, but different request methods, instead of this:
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from pyramid.view import view_config from pyramid.response import Response
class RESTView(object):
def __init__(self, request):
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12.2. @VIEW_DEFAULTS CLASS DECORATOR
6self.request = request
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8 @view_config(route_name=’rest’, request_method=’GET’)
9def get(self):
10 return Response(’get’)
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12@view_config(route_name=’rest’, request_method=’POST’)
13def post(self):
14return Response(’post’)
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16@view_config(route_name=’rest’, request_method=’DELETE’)
17def delete(self):
18return Response(’delete’)
You can do this:
1 from pyramid.view import view_defaults
2 from pyramid.view import view_config
3 from pyramid.response import Response
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5 @view_defaults(route_name=’rest’)
6 class RESTView(object):
7 def __init__(self, request):
8self.request = request
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10@view_config(request_method=’GET’)
11def get(self):
12return Response(’get’)
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14@view_config(request_method=’POST’)
15def post(self):
16return Response(’post’)
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18@view_config(request_method=’DELETE’)
19def delete(self):
20return Response(’delete’)
In the above example, we were able to take the route_name=’rest’ argument out of the call to each individual @view_config statement, because we used a @view_defaults class decorator to provide the argument as a default to each view method it possessed.
Arguments passed to @view_config will override any default passed to @view_defaults.
The view_defaults class decorator can also provide defaults to the pyramid.config.Configurator.add_view() directive when a decorated class is passed to that directive as its view argument. For example, instead of this:
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12. VIEW CONFIGURATION
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from pyramid.response import Response |
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from pyramid.config import Configurator |
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class RESTView(object): |
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def __init__(self, request): |
6self.request = request
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8def get(self):
9return Response(’get’)
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11def post(self):
12return Response(’post’)
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14def delete(self):
15return Response(’delete’)
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17if __name__ == ’__main__’:
18config = Configurator()
19config.add_route(’rest’, ’/rest’)
20config.add_view(
21RESTView, route_name=’rest’, attr=’get’, request_method=’GET’)
22config.add_view(
23RESTView, route_name=’rest’, attr=’post’, request_method=’POST’)
24config.add_view(
25RESTView, route_name=’rest’, attr=’delete’, request_method=’DELETE’)
To reduce the amount of repetion in the config.add_view statements, we can move the route_name=’rest’ argument to a @view_default class decorator on the RESTView class:
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from pyramid.view import view_config from pyramid.response import Response from pyramid.config import Configurator
@view_defaults(route_name=’rest’) class RESTView(object):
def __init__(self, request): self.request = request
def get(self):
return Response(’get’)
def post(self):
return Response(’post’)
def delete(self):
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12.2. @VIEW_DEFAULTS CLASS DECORATOR
17 return Response(’delete’)
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19if __name__ == ’__main__’:
20config = Configurator()
21config.add_route(’rest’, ’/rest’)
22config.add_view(RESTView, attr=’get’, request_method=’GET’)
23config.add_view(RESTView, attr=’post’, request_method=’POST’)
24config.add_view(RESTView, attr=’delete’, request_method=’DELETE’)
pyramid.view.view_defaults accepts the same set of arguments that pyramid.view.view_config does, and they have the same meaning. Each argument passed to view_defaults provides a default for the view configurations of methods of the class it’s decorating.
Normal Python inheritance rules apply to defaults added via view_defaults. For example:
1 @view_defaults(route_name=’rest’) 2 class Foo(object):
3pass
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5 class Bar(Foo):
6pass
The Bar class above will inherit its view defaults from the arguments passed to the view_defaults decorator of the Foo class. To prevent this from happening, use a view_defaults decorator without any arguments on the subclass:
1 @view_defaults(route_name=’rest’) 2 class Foo(object):
3pass
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5 @view_defaults()
6 class Bar(Foo):
7pass
The view_defaults decorator only works as a class decorator; using it against a function or a method will produce nonsensical results.
12.2.1 Configuring View Security
If an authorization policy is active, any permission attached to a view configuration found during view lookup will be verified. This will ensure that the currently authenticated user possesses that permission
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