Metadata-Version: 1.1
Name: paper
Version: 0.2.0
Summary: Keep generated fields in cache for your Django models.
Home-page: https://github.com/ActivKonnect/paper
Author: Rémy Sanchez
Author-email: remy.sanchez@activkonnect.com
License: WTFPL
Description: Paper
        =====
        
        .. image:: https://travis-ci.org/ActivKonnect/paper.svg?branch=develop
            :target: https://travis-ci.org/ActivKonnect/paper
        
        Keep generated fields in cache for your Django models.
        
        Usage
        ~~~~~
        
        You have two options: ``@paper`` will help you to create a calculated field that is stored in
        Django's cache, and ``@cardboard`` will create a regular field in your model and update it in
        database automatically.
        
        @paper
        ------
        
        Just like the ``@property`` decorator, you just need to use the ``@paper`` decorator, that will
        transform a method of your class into a cached property.
        
        .. code-block:: python
        
           class ModelA(models.Model):
               name = models.TextField()
        
               @paper(1, [
                   ('testpaper.ModelB', lambda i: ModelA.objects.filter(children=i)),
               ])
               def count(self):
                   return ModelA.objects\
                       .filter(pk=self.pk)\
                       .annotate(count=Coalesce(Sum('children__count'), 0))\
                       .values_list('count', flat=True)[0]
        
        
           class ModelB(models.Model):
               parent = models.ForeignKey('ModelA', related_name='children')
               count = models.IntegerField()
        
        ``@paper`` takes 2 arguments:
        
        - The method's version number, in case you want to change the format of what is returned. By
          example, imagine you're returning a complex denormalized data structure. If at some point you
          want to add some data in it, you can simply bump the version number and it will invalidate the
          caches automatically.
        - A list of model/lister couples.
          - The model is either a model class, either an 'app.Model' string
          - The lister takes a single argument which is an instance of the updated model (here a ModelB
          objet) and returns a list of affected objects to invalidate (here a queryset of ModelA objects).
        
        The value will be cached using Django's default cache. Please note that this requires the cache to
        be shared across all your web worker instances, otherwise invalidation won't have any the intended
        effect.
        
        Invalidation is based on Django signals, so it requires ``save()`` or ``delete()`` to be called in
        order to work correctly. Bulk/SQL operations won't be detected automatically.
        
        @cardboard
        ----------
        
        Use is very similar to ``@paper``, the main differences being the absence of versioning and the fact
        that result is going to be stored in the model itself instead of caching it.
        
        .. code-block:: python
        
           class ModelA(models.Model):
               name = models.TextField()
        
               @cardboard(models.IntegerField(default=0), [
                   ('testpaper.ModelB', lambda i: ModelA.objects.filter(children=i)),
               ])
               def count(self):
                   return ModelA.objects\
                       .filter(pk=self.pk)\
                       .annotate(count=Coalesce(Sum('children__count'), 0))\
                       .values_list('count', flat=True)[0]
        
        
           class ModelB(models.Model):
               parent = models.ForeignKey('ModelA', related_name='children')
               count = models.IntegerField()
        
        ``@cardboard`` takes two arguments:
        
        - The field that will be used to store results. You have to give it a sensible default value,
          because no calculation will be made upon object creation. Calculation are only triggered by the
          ``dependencies`` functions.
        - A list of dependencies, just like in ``@paper``.
        
        The same remark goes for this technique being ``save()``/``delete()`` driven: bulk or SQL operations
        won't trigger recalculation.
        
        Licence
        ~~~~~~~
        
        This software is licenced by ActivKonnect under the terms of the WTFPL.
        
Platform: UNKNOWN
Classifier: Intended Audience :: Developers
Classifier: License :: Other/Proprietary License
Classifier: Programming Language :: Python
Classifier: Programming Language :: Python :: 2
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3
Classifier: Programming Language :: Python :: 3.3
Classifier: Programming Language :: Python :: 3.4
Classifier: Topic :: Internet :: WWW/HTTP :: Dynamic Content
Classifier: Framework :: Django
Classifier: Framework :: Django :: 1.7
Classifier: Framework :: Django :: 1.8
Classifier: Development Status :: 3 - Alpha
