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Diffstat (limited to 'docs/narr/hooks.rst')
| -rw-r--r-- | docs/narr/hooks.rst | 108 |
1 files changed, 97 insertions, 11 deletions
diff --git a/docs/narr/hooks.rst b/docs/narr/hooks.rst index b5efc0df1..43bf48289 100644 --- a/docs/narr/hooks.rst +++ b/docs/narr/hooks.rst @@ -257,6 +257,95 @@ already constructed a :term:`configurator` it can also be registered via the config.set_request_factory(MyRequest) .. index:: + single: request method + +.. _adding_request_method: + +Adding Methods or Properties to Request Object +---------------------------------------------- + +.. versionadded:: 1.4. + +Since each Pyramid application can only have one :term:`request` factory, +:ref:`changing the request factory <changing_the_request_factory>` +is not that extensible, especially if you want to build composable features +(e.g., Pyramid add-ons and plugins). + +A lazy property can be registered to the request object via the +:meth:`pyramid.config.Configurator.add_request_method` API. This allows you +to specify a callable that will be available on the request object, but will not +actually execute the function until accessed. + +.. warning:: This will silently override methods and properties from + :term:`request factory` that have the same name. + +.. code-block:: python + :linenos: + + from pyramid.config import Configurator + + def total(request, *args): + return sum(args) + + def prop(request): + print "getting the property" + return "the property" + + config = Configurator() + config.add_request_method(total) + config.add_request_method(prop, reify=True) + +In the above example, ``total`` is added as a method. However, ``prop`` is added +as a property and its result is cached per-request by setting ``reify=True``. +This way, we eliminate the overhead of running the function multiple times. + + >>> request.total(1, 2, 3) + 6 + >>> request.prop + getting the property + the property + >>> request.prop + the property + +To not cache the result of ``request.prop``, set ``property=True`` instead of +``reify=True``. + +Here is an example of passing a class to ``Configurator.add_request_method``: + +.. code-block:: python + :linenos: + + from pyramid.config import Configurator + from pyramid.decorator import reify + + class ExtraStuff(object): + + def __init__(self, request): + self.request = request + + def total(self, *args): + return sum(args) + + # use @property if you don't want to cache the result + @reify + def prop(self): + print "getting the property" + return "the property" + + config = Configurator() + config.add_request_method(ExtraStuff, 'extra', reify=True) + +We attach and cache an object named ``extra`` to the ``request`` object. + + >>> request.extra.total(1, 2, 3) + 6 + >>> request.extra.prop + getting the property + the property + >>> request.extra.prop + the property + +.. index:: single: before render event single: adding renderer globals @@ -336,9 +425,9 @@ when adding renderer global values exists in :ref:`adding_renderer_globals`. Adding Renderer Globals (Deprecated) ------------------------------------ -.. warning:: this feature is deprecated as of Pyramid 1.1. A non-deprecated - mechanism which allows event subscribers to add renderer global values - is documented in :ref:`beforerender_event`. +.. deprecated:: 1.1 + An alternative mechanism which allows event subscribers to add renderer + global values is documented in :ref:`beforerender_event`. Whenever :app:`Pyramid` handles a request to perform a rendering (after a view with a ``renderer=`` configuration attribute is invoked, or when any of @@ -635,13 +724,13 @@ See :meth:`pyramid.config.add_resource_url_adapter` for more information. Changing How Pyramid Treats View Responses ------------------------------------------ +.. versionadded:: 1.1 + It is possible to control how Pyramid treats the result of calling a view callable on a per-type basis by using a hook involving :meth:`pyramid.config.Configurator.add_response_adapter` or the :class:`~pyramid.response.response_adapter` decorator. -.. note:: This feature is new as of Pyramid 1.1. - Pyramid, in various places, adapts the result of calling a view callable to the :class:`~pyramid.interfaces.IResponse` interface to ensure that the object returned by the view callable is a "true" response object. The vast @@ -936,8 +1025,8 @@ For full details, please read the `Venusian documentation Registering "Tweens" -------------------- -.. note:: Tweens are a feature which were added in Pyramid 1.2. They are - not available in any previous version. +.. versionadded:: 1.2 + Tweens A :term:`tween` (a contraction of the word "between") is a bit of code that sits between the Pyramid router's main request handling function and the @@ -1241,10 +1330,7 @@ implict and explicit tween chains used by an application. See Adding A Third Party View, Route, or Subscriber Predicate --------------------------------------------------------- -.. note:: - - Third-party view, route, and subscriber predicates are a feature new as of - Pyramid 1.4. +.. versionadded:: 1.4 .. _view_and_route_predicates: |