90beceeb7b
Rename the "doc" folder to "docs" to be consistent with the tox env name. RTD also seems to expect "docs" as its first choice, even though it will discover "doc" as well.
50 lines
1.3 KiB
ReStructuredText
50 lines
1.3 KiB
ReStructuredText
.. _hooks:
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Hooks
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=====
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Falcon supports *before* and *after* hooks. You install a hook simply by
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applying one of the decorators below, either to an individual responder or
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to an entire resource.
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For example, consider this hook that validates a POST request for
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an image resource:
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.. code:: python
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def validate_image_type(req, resp, resource, params):
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if req.content_type not in ALLOWED_IMAGE_TYPES:
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msg = 'Image type not allowed. Must be PNG, JPEG, or GIF'
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raise falcon.HTTPBadRequest('Bad request', msg)
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You would attach this hook to an ``on_post`` responder like so:
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.. code:: python
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@falcon.before(validate_image_type)
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def on_post(self, req, resp):
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pass
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Or, suppose you had a hook that you would like to apply to *all*
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responders for a given resource. In that case, you would simply
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decorate the resource class:
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.. code:: python
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@falcon.before(extract_project_id)
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class Message(object):
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def on_post(self, req, resp):
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pass
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def on_get(self, req, resp):
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pass
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Falcon :ref:`middleware components <middleware>` can also be used to insert
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logic before and after requests. However, unlike hooks,
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:ref:`middleware components <middleware>` are triggered **globally** for all
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requests.
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.. automodule:: falcon
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:members: before, after
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:undoc-members:
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