pecan.hooks
– Pecan Hooks¶
The pecan.hooks
module includes support for creating Pecan
hooks
which are a simple way to hook into the request processing
of requests coming into your application to perform cross-cutting tasks.
-
class
pecan.hooks.
PecanHook
¶ Bases:
object
A base class for Pecan hooks. Inherit from this class to create your own hooks. Set a priority on a hook by setting the
priority
attribute for the hook, which defaults to 100.-
after
(state)¶ Override this method to create a hook that gets called after the request has been handled by the controller.
Parameters: state – The Pecan state
object for the current request.
-
before
(state)¶ Override this method to create a hook that gets called after routing, but before the request gets passed to your controller.
Parameters: state – The Pecan state
object for the current request.
-
on_error
(state, e)¶ Override this method to create a hook that gets called upon an exception being raised in your controller.
Parameters: - state – The Pecan
state
object for the current request. - e – The
Exception
object that was raised.
- state – The Pecan
-
on_route
(state)¶ Override this method to create a hook that gets called upon the start of routing.
Parameters: state – The Pecan state
object for the current request.
-
-
class
pecan.hooks.
TransactionHook
(start, start_ro, commit, rollback, clear)¶ Bases:
pecan.hooks.PecanHook
Parameters: - start – A callable that will bind to a writable database and start a transaction.
- start_ro – A callable that will bind to a readable database.
- commit – A callable that will commit the active transaction.
- rollback – A callable that will roll back the active transaction.
- clear – A callable that will clear your current context.
A basic framework hook for supporting wrapping requests in transactions. By default, it will wrap all but
GET
andHEAD
requests in a transaction. Override theis_transactional
method to define your own rules for what requests should be transactional.-
after
(state)¶ Override this method to create a hook that gets called after the request has been handled by the controller.
Parameters: state – The Pecan state
object for the current request.
-
before
(state)¶ Override this method to create a hook that gets called after routing, but before the request gets passed to your controller.
Parameters: state – The Pecan state
object for the current request.
-
is_transactional
(state)¶ Decide if a request should be wrapped in a transaction, based upon the state of the request. By default, wraps all but
GET
andHEAD
requests in a transaction, along with respecting thetransactional
decorator from :mod:pecan.decorators.Parameters: state – The Pecan state object for the current request.
-
on_error
(state, e)¶ Override this method to create a hook that gets called upon an exception being raised in your controller.
Parameters: - state – The Pecan
state
object for the current request. - e – The
Exception
object that was raised.
- state – The Pecan
-
on_route
(state)¶ Override this method to create a hook that gets called upon the start of routing.
Parameters: state – The Pecan state
object for the current request.
-
class
pecan.hooks.
HookController
¶ Bases:
object
A base class for controllers that would like to specify hooks on their controller methods. Simply create a list of hook objects called
__hooks__
as a class attribute of your controller.
-
class
pecan.hooks.
RequestViewerHook
(config=None, writer=<_io.TextIOWrapper name='<stdout>' mode='w' encoding='utf-8'>, terminal=True, headers=True)¶ Bases:
pecan.hooks.PecanHook
Parameters: - config – A (optional) dictionary that can hold
items
and/orblacklist
keys. - writer – The stream writer to use. Can redirect output to other
streams as long as the passed in stream has a
write
callable method. - terminal – Outputs to the chosen stream writer (usually the terminal)
- headers – Sets values to the X-HTTP headers
Returns some information about what is going on in a single request. It accepts specific items to report on but uses a default list of items when none are passed in. Based on the requested
url
, items can also be blacklisted. Configuration is flexible, can be passed in (or not) and can contain some or all the keys supported.items
This key holds the items that this hook will display. When this key is passed only the items in the list will be used. Valid items are any item that the
request
object holds, by default it uses the following:- path
- status
- method
- controller
- params
- hooks
Note
This key should always use a
list
of items to use.blacklist
This key holds items that will be blacklisted based on
url
. If there is a need to omit urls that start with /javascript, then this key would look like:'blacklist': ['/javascript']
As many blacklisting items as needed can be contained in the list. The hook will verify that the url is not starting with items in this list to display results, otherwise it will get omitted.
Note
This key should always use a
list
of items to use.For more detailed documentation about this hook, please see RequestViewerHook
-
after
(state)¶ Override this method to create a hook that gets called after the request has been handled by the controller.
Parameters: state – The Pecan state
object for the current request.
-
format_hooks
(hooks)¶ Tries to format the hook objects to be more readable Specific to Pecan (not available in the request object)
-
get_controller
(state)¶ Retrieves the actual controller name from the application Specific to Pecan (not available in the request object)
- config – A (optional) dictionary that can hold