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Diffstat (limited to 'docs/narr/traversal.rst')
| -rw-r--r-- | docs/narr/traversal.rst | 59 |
1 files changed, 21 insertions, 38 deletions
diff --git a/docs/narr/traversal.rst b/docs/narr/traversal.rst index 8e7f93a1b..454bb5620 100644 --- a/docs/narr/traversal.rst +++ b/docs/narr/traversal.rst @@ -22,10 +22,13 @@ resource found as the result of a traversal becomes the subsystem is used to find some view code willing to "publish" this resource by generating a :term:`response`. -Using :term:`Traversal` to map a URL to code is optional. It is often -less easy to understand than :term:`URL dispatch`, so if you're a rank -beginner, it probably makes sense to use URL dispatch to map URLs to -code instead of traversal. In that case, you can skip this chapter. +.. note:: + + Using :term:`Traversal` to map a URL to code is optional. If you're creating + your first Pyramid application it probably makes more sense to use :term:`URL + dispatch` to map URLs to code instead of traversal, as new Pyramid developers + tend to find URL dispatch slightly easier to understand. If you use URL + dispatch, you needn't read this chapter. .. index:: single: traversal details @@ -143,35 +146,15 @@ refer to a root factory defined in a different module. If no :term:`root factory` is passed to the :app:`Pyramid` :term:`Configurator` constructor, or if the ``root_factory`` value -specified is ``None``, a *default* root factory is used. The default +specified is ``None``, a :term:`default root factory` is used. The default root factory always returns a resource that has no child resources; it is effectively empty. Usually a root factory for a traversal-based application will be more -complicated than the above ``Root`` class; in particular it may be -associated with a database connection or another persistence mechanism. - -.. sidebar:: Emulating the Default Root Factory - - For purposes of understanding the default root factory better, we'll note - that you can emulate the default root factory by using this code as an - explicit root factory in your application setup: - - .. code-block:: python - :linenos: - - class Root(object): - def __init__(self, request): - pass - - config = Configurator(root_factory=Root) - - The default root factory is just a really stupid object that has no - behavior or state. Using :term:`traversal` against an application that - uses the resource tree supplied by the default root resource is not very - interesting, because the default root resource has no children. Its - availability is more useful when you're developing an application using - :term:`URL dispatch`. +complicated than the above ``Root`` class; in particular it may be associated +with a database connection or another persistence mechanism. The above +``Root`` class is analogous to the default root factory present in Pyramid. The +default root factory is very simple and not very useful. .. note:: @@ -286,7 +269,7 @@ system uses this algorithm to find a :term:`context` resource and a return resource "C". #. Traversal ends when a) the entire path is exhausted or b) when any - resouce raises a :exc:`KeyError` from its ``__getitem__`` or c) when any + resource raises a :exc:`KeyError` from its ``__getitem__`` or c) when any non-final path element traversal does not have a ``__getitem__`` method (resulting in a :exc:`AttributeError`) or d) when any path element is prefixed with the set of characters ``@@`` (indicating that the characters @@ -356,13 +339,13 @@ when this request comes in that we're traversing the following resource tree: Here's what happens: -- :mod:`traversal` traverses the root, and attempts to find "foo", which it +- :term:`traversal` traverses the root, and attempts to find "foo", which it finds. -- :mod:`traversal` traverses "foo", and attempts to find "bar", which it +- :term:`traversal` traverses "foo", and attempts to find "bar", which it finds. -- :mod:`traversal` traverses "bar", and attempts to find "baz", which it does +- :term:`traversal` traverses "bar", and attempts to find "baz", which it does not find (the "bar" resource raises a :exc:`KeyError` when asked for "baz"). @@ -389,7 +372,7 @@ Using the :term:`view name` (``baz``) and the type, view lookup asks the Let's say that view lookup finds no matching view type. In this circumstance, the :app:`Pyramid` :term:`router` returns the result of the -:term:`not found view` and the request ends. +:term:`Not Found View` and the request ends. However, for this tree: @@ -407,16 +390,16 @@ However, for this tree: The user asks for ``http://example.com/foo/bar/baz/biz/buz.txt`` -- :mod:`traversal` traverses "foo", and attempts to find "bar", which it +- :term:`traversal` traverses "foo", and attempts to find "bar", which it finds. -- :mod:`traversal` traverses "bar", and attempts to find "baz", which it +- :term:`traversal` traverses "bar", and attempts to find "baz", which it finds. -- :mod:`traversal` traverses "baz", and attempts to find "biz", which it +- :term:`traversal` traverses "baz", and attempts to find "biz", which it finds. -- :mod:`traversal` traverses "biz", and attempts to find "buz.txt" which it +- :term:`traversal` traverses "biz", and attempts to find "buz.txt" which it does not find. The fact that it does not find a resource related to "buz.txt" at this point |