79 lines
2.1 KiB
ReStructuredText
79 lines
2.1 KiB
ReStructuredText
.. _ref-cache:
|
|
.. module:: trytond.cache
|
|
|
|
=====
|
|
Cache
|
|
=====
|
|
|
|
.. class:: Cache(name[, size_limit[, duration[, context]]])
|
|
|
|
The class is used to cache values between server requests. The ``name`` should
|
|
be unique and it's used to identify the cache. We usually use
|
|
``<class_name>.<content_name>`` to make it unique. The ``size_limit`` parameter
|
|
can be used to limit the number of values cached and it has 1024 as the default
|
|
value. The ``duration`` parameter defines how long a cached value stays valid
|
|
but if it is not set the value remains valid until it is cleared. And the
|
|
``context`` parameter is used to indicate if the cache depends on the user
|
|
context and is true by default. The cache is cleaned on :class:`Transaction`
|
|
starts and resets on :class:`Transaction` commit or rollback.
|
|
|
|
.. warning::
|
|
As there is no deepcopy of the values cached, they must never be mutated
|
|
after being set in or retrieved from the cache.
|
|
..
|
|
|
|
.. attribute:: hit
|
|
|
|
Count the number of times the cache returned a cached value.
|
|
|
|
.. attribute:: miss
|
|
|
|
Count the number of times the cache did not contain the key.
|
|
|
|
.. classmethod:: stats()
|
|
|
|
Yield statistics for each instance.
|
|
|
|
.. method:: get(key[, default])
|
|
|
|
Retrieve the value of the key in the cache. If a ``default`` is specified it
|
|
will be returned when the key is missing otherwise it will return ``None``.
|
|
|
|
.. method:: set(key, value)
|
|
|
|
Sets the ``value`` of the ``key`` in the cache.
|
|
|
|
.. method:: clear()
|
|
|
|
Clears all the keys in the cache.
|
|
|
|
.. classmethod:: clear_all()
|
|
|
|
Clears all cache instances.
|
|
|
|
.. classmethod:: sync(transaction)
|
|
|
|
Synchronize cache instances using transaction.
|
|
|
|
.. method:: sync_since(value)
|
|
|
|
Return ``True`` if the last synchronization was done before ``value``.
|
|
|
|
.. classmethod:: commit(transaction)
|
|
|
|
Apply cache changes from transaction.
|
|
|
|
.. classmethod:: rollback(transaction)
|
|
|
|
Remove cache changes from transaction.
|
|
|
|
.. classmethod:: drop(dbname)
|
|
|
|
Drops all the caches for database ``dbname``
|
|
|
|
.. note::
|
|
By default Tryton uses a MemoryCache, but this behaviour can be overridden
|
|
by setting a fully qualified name of an alternative class defined in the
|
|
configuration ``class`` of the ``cache`` section.
|
|
..
|