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https://github.com/eea/eea.cache

Easy use memcached cache with Zope and Plone
https://github.com/eea/eea.cache

memcached plone plone-addon plone4x plone5x varnish

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Easy use memcached cache with Zope and Plone

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README 

        
=========

EEA Cache

=========

.. image:: https://ci.eionet.europa.eu/buildStatus/icon?job=eea/eea.cache/develop&subject=develop

  :target: https://ci.eionet.europa.eu/job/eea/job/eea.cache/job/develop/display/redirect

  :alt: Develop

.. image:: https://ci.eionet.europa.eu/buildStatus/icon?job=eea/eea.cache/master&subject=master

  :target: https://ci.eionet.europa.eu/job/eea/job/eea.cache/job/master/display/redirect

  :alt: Master

.. image:: https://img.shields.io/github/v/release/eea/eea.cache

  :target: https://pypi.org/project/eea.cache/

  :alt: Release



Introduction

============



This package combines the features from lovely.memcached and plone.memoize.ram.

It provides a decorator and utility for Memcaches at EEA.

The decorator allows you set dependencies known by eea.cache



.. note ::



  This add-on doesn't do anything by itself. It needs to be integrated by a

  developer within your own products. For reference you can check

  the `eea.app.visualization`_ package.



Contents

========



.. contents::



Main features

=============



1. Extends and overrides plone.memoize cache adapters to work with memcache

2. Provides an extended @cache decorator that supports:



   * cache lifetime override per method

   * dependencies string in order to bulk invalidate cache

   * auto-invalidation of cache when ObjectModifiedEvent is triggered



3. Possibility to manually invalidate cache via URL.



Install

=======



* Add eea.cache to your eggs and zcml section in your buildout and re-run buildout::



    eggs =

      ...

      eea.cache



    zcml =

      ...

      eea.cache

      eea.cache-overrides



* You can download a sample buildout from https://github.com/eea/eea.cache/tree/master/buildouts/plone4

* Install eea.cache within Site Setup > Add-ons

* Start memcache::



  $ bin/memcached start



Dependencies

============



* `python-memcached`_

* `pylibmc`_ (optional, for better performance)

* `plone.memoize`_

* `plone.uuid`_



Source code

===========



Latest source code (Zope 2 compatible):

  * `Plone Collective on Github `_

  * `EEA on Github `_



Cache decorator

===============



::



    >>> def key(method, self):

    ...     return method.__name__



    >>> from eea.cache import cache

    >>> @cache(key, dependencies=["frontpage"])

    ... def myMethod(num):

    ...     return num*num



Lets clear any running memcache::



    >>> from eea.cache.event import InvalidateMemCacheEvent

    >>> from zope.event import notify

    >>> notify(InvalidateMemCacheEvent(raw=True, dependencies=['frontpage']))



Our myMethod will now be cached with the key returned from the method 'key' and

with dependency 'frontpage'::



    >>> myMethod(2)

    4

    >>> myMethod(3)

    4



    >>> notify(InvalidateMemCacheEvent(raw=True, dependencies=['frontpage']))

    >>> myMethod(3)

    9



Cache lifetime

==============

By default your content is cached in memcache for one hour (3600 seconds). You

can change this by adding an **int** property within: ZMI > portal_properties >

site_properties called **memcached_defaultLifetime** and set it's value to

**86400** (one day) for example.



Cache lifetime override per key

-------------------------------



Starting with eea.cache 5.1 you can also pass a lifetime key with the duration

in seconds which will override the defaultLifetime either given from the

portal property or the default one from lovely.memcached of 3600 seconds::



    ex: in order to cache the result only for 4 minutes

    >>> @cache(key, dependencies=["frontpage"], lifetime=240)

    ... def myMethod(num):

    ...     return num*num



Invalidate cache

================

If you use cache decorator for BrowserView methods or directly on Zope objects

methods cache will be **automatically invalidated** when object is modified

(ObjectModifiedEvent is triggered)::



    >>> from Products.Five.browser import BrowserView



    >>> class XXX(BrowserView):

    ...     @cache(key)

    ...     def title(self):

    ...         return self.context.title_or_id()



You can disable auto invalidation by providing the auto_invalidate param to @cache

decorator::



    >>> @cache(key, auto_invalidate=False)

    ... def title(self):

    ...     return self.context.title_or_id()



memcache.invalidate

-------------------

In order to manually invalidate memcached cache per object this package

provides a browser view called **memcache.invalidate**.

It will invalidate all memcached methods associated with current object's UID::



    http://localhost:2020/Plone/front-page/memcache.invalidate



You can also manually invalidate related items and back references::



    http://localhost:2020/Plone/front-page/memcache.invalidate/relatedItems



    http://localhost:2020/Plone/front-page/memcache.invalidate/backRefs



By default this method can be called by users with these roles:



* Editor

* CommonEditor

* Owner

* Manager



varnish.invalidate

-------------------

In order to manually invalidate memcached cache per object this package

provides a browser view called **varnish.invalidate**.

It will invalidate all memcached methods associated with current object's UID::



    http://localhost:2020/Plone/front-page/varnish.invalidate



You can also manually invalidate related items and back references::



    http://localhost:2020/Plone/front-page/varnish.invalidate/relatedItems



    http://localhost:2020/Plone/front-page/varnish.invalidate/backRefs



By default this method can be called by users with these roles:



* Editor

* CommonEditor

* Owner

* Manager



cache.invalidate

----------------

In order to manually invalidate cache (memcached and varnish) per object this

package provides a browser view called **cache.invalidate**.

It will call memcache.invalidate and varnish.invalidate::



    http://localhost:2020/Plone/front-page/cache.invalidate



You can also manually invalidate related items and back references::



    http://localhost:2020/Plone/front-page/cache.invalidate/relatedItems



    http://localhost:2020/Plone/front-page/cache.invalidate/backRefs



By default this method can be called by users with these roles:



* Editor

* CommonEditor

* Owner

* Manager



cache.settings

--------------

There is also a Cache Tab per object where you can manually select which cache

to invalidate. By default, you can invalidate memcache and varnish. You also

have the possibility to invalidate memcache and/or varnish for related items

and also fo back references.



This form can be extended with more options. For a more detailed

example see `eea.pdf`_



**configure.zcml**::



  



  



**behavior.py**::



  # Model

  class IExtraSettings(model.Schema):

      """ Extra settings

      """

      pdf = schema.Bool(

          title=_(u"PDF"),

          description=_(u"Invalidate latest generated PDF file"),

          required=False,

          default=False

      )



  # Behaviour

  class ExtraBehavior(object):

      implements(IExtraSettings)

      adapts(IPDFAware)



      def __init__(self, context):

          self.context = context



      @property

      def pdf(self):

          """ PDF

          """

          return False



      @pdf.setter

      def pdf(self, value):

          """ Invalidate last generated PDF?

          """

          if not value:

              return



          removePdfFiles()



  # Form

  class ExtraSettings(extensible.FormExtender):

      adapts(IPDFAware, ILayer, SettingsForm)



      def __init__(self, context, request, form):

          self.context = context

          self.request = request

          self.form = form



      def update(self):

          """ Extend form

          """

          self.add(IExtraSettings, prefix="extra")

          self.move('pdf', after='varnish', prefix='extra')



Copyright and license

=====================

The Initial Owner of the Original Code is European Environment Agency (EEA).

All Rights Reserved.



The eea.cache (the Original Code) is free software;

you can redistribute it and/or modify it under the terms of the GNU

General Public License as published by the Free Software Foundation;

either version 2 of the License, or (at your option) any later

version.



More details under docs/License.txt



Funding and project management

==============================



EEA_ - European Environment Agency (EU)



.. _EEA: https://www.eea.europa.eu/

.. _`EEA Cache`: https://eea.github.io/docs/eea.cache

.. _`plone.recipe.zope2instance`: https://pypi.python.org/pypi/plone.recipe.zope2instance

.. _`eea.app.visualization`: https://eea.github.io/docs/eea.app.visualization

.. _`plone.memoize`: https://pypi.python.org/pypi/plone.memoize

.. _`pylibmc`: https://pypi.python.org/pypi/pylibmc

.. _`plone.uuid`: https://pypi.python.org/pypi/plone.uuid

.. _`python-memcached`: https://pypi.python.org/pypi/python-memcached

.. _`eea.pdf`: https://eea.github.io/docs/eea.pdf