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django-diffs-0.1.9
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مشاهده بیشتر
تبلیغات ما
مشتریان به طور فزاینده ای آنلاین هستند. تبلیغات می تواند به آنها کمک کند تا کسب و کار شما را پیدا کنند.
مشاهده بیشتر
تبلیغات ما
مشتریان به طور فزاینده ای آنلاین هستند. تبلیغات می تواند به آنها کمک کند تا کسب و کار شما را پیدا کنند.
مشاهده بیشتر
تبلیغات ما
مشتریان به طور فزاینده ای آنلاین هستند. تبلیغات می تواند به آنها کمک کند تا کسب و کار شما را پیدا کنند.
مشاهده بیشترتوضیحات
Keep a record of diffs made to a Django model or collection of models
| ویژگی | مقدار |
|---|---|
| سیستم عامل | - |
| نام فایل | django-diffs-0.1.9 |
| نام | django-diffs |
| نسخه کتابخانه | 0.1.9 |
| نگهدارنده | [] |
| ایمیل نگهدارنده | [] |
| نویسنده | Sam Bolgert |
| ایمیل نویسنده | sbolgert@gmail.com |
| آدرس صفحه اصلی | https://github.com/linuxlewis/django-diffs |
| آدرس اینترنتی | https://pypi.org/project/django-diffs/ |
| مجوز | MIT |
Django Diffs
------------
.. image:: https://travis-ci.org/linuxlewis/django-diffs.svg?branch=master
:target: https://travis-ci.org/linuxlewis/django-diffs
Django diffs allows models to be registered to cache it's changes (or diffs) over a fixed time period.
The diffs are stored in redis using a SortedSet and accessed via a manager-like object on the registered django model class.
It's compatible with Python 2/3 and Django 1.8 and above. It requires an available redis server.
Table of Contents
-----------------
- `Getting Started <#getting-started>`__
- `Configuration <#configuration>`__
- `Pruning Diffs <#pruning-diffs>`__
- `Custom Serialization <#custom-serialization>`__
- `Related models <#related-models>`__
How does it Work?
-----------------
Models are registered with the ``@diffs.register`` decorator and their changes are serialized and saved to redis on signals.
The decorator installs django-dirtyfields to the model on registration to get the changed fields of the model instance.
Changes can be accessed via the ``diffs`` manager on the registered model. The diffs manager returns a list of ``Diff``
objects that have properties of ``data``, ``created``, and ``timestamp``.
The manager can be accessed via the class like ``Question.diffs`` or like a related manager on the instance ``instance.diffs``.
Here's a quick example.
.. code:: python
# models.py
import diffs
@diffs.register
class Question(models.Model):
question_text = models.CharField(max_length=200)
pub_date = models.DateTimeField('date published')
question = Question.objects.create(question_text='What is life?')
question.question_text = 'What is python?'
question.save()
for diff in question.diffs:
print(diff.timestamp)
print(diff.data)
print(diff.created)
diffs = Question.diffs.get_by_object_id(question.id)
Why?
----
You need to cache the changes to a single django model or collection of models for a fixed time period.
Tracking the changes prevents clients from having to re-request all of the model data which is assumed to be costly.
Getting Started
---------------
- Add ``django-diffs`` to ``requirements.txt``
.. code:: bash
pip install django-diffs
- Add ``diffs`` to ``INSTALLED_APPS``
.. code:: python
INSTALLED_APPS = (
'diffs',
)
- Register a Model
.. code:: python
# models.py
import diffs
@diffs.register
class Question(models.Model):
question_text = models.CharField(max_length=200)
pub_date = models.DateTimeField('date published')
That's it! Changes will now be tracked automatically for this model.
Configuration
-------------
Django-diffs can be configured via ``django.conf.settings``. Below is the default configuration
.. code:: python
# settings.py
DIFFS_SETTINGS = {
'redis': {
'host': 'localhost',
'port': 6379,
'db': 0,
},
'max_element_age': 60*60,
'use_transactions': True,
'test_mode': False
}
The following keys are supported for ``DIFFS_SETTINGS``
``redis`` -- A dictionary with the keys ``host``, ``port`` and ``db`` for details of the redis server.
``max_element_age`` -- Defines the number of seconds a single diff should be allowed to live. This is used in the pruning script
to remove old elements from the set.
``use_transactions`` -- Boolean to configure django-diffs using Django's ``connection.on_commit`` callback registry. When enabled
django-diffs will defer persistence to ``on_commit``.
``test_mode`` -- Boolean to configure using test mode. Test mode uses ``fake_redis`` instead of real ``redis`` so a server isn't required.
Use this mode when running your unittests.
Pruning Diffs
-------------
By default redis only allows you to set an expire on an entire key. You cannot set an expiry per element in a set or sorted set.
To work around this django-diffs sets the current unix timestamp as the SortedSet element score. Items can then be easily removed
using the redis command ``ZREMRANGEBYSCORE``.
All of this has been handled for you in the custom management command ``prune_diffs``. Run this on a cron schedule to keep your
cache up to date.
.. code:: bash
python manage.py prune_diffs
Custom Serialization
--------------------
By default django-diffs uses ``django.core.serializers`` module to serialize the diff to json.
To use your own custom serialization format just implement the ``serialize_diff`` method
on your model. It will be passed the list of ``dirty_fields`` and the ``created`` kwarg.
.. code:: python
# models.py
import diffs
@diffs.register
class Question(models.Model):
question_text = models.CharField(max_length=200)
pub_date = models.DateTimeField('date published')
def serialize_diff(self, dirty_fields, created=False):
return {'fields': dirty_fields}
question = Question.objects.create(question_text='What will happen?')
Question.diffs.get_by_object_id(question.id)[-1].data
# {'fields': ['question_name']}
Related models
--------------
Sometimes you want to track changes on a collection of related models.
These could be individual items part of a larger Report object.
Django-diffs allows you to set a parent objects by implementing ``get_diff_parent`` on
the child model. It must return a model instance with an id defined.
.. code:: python
# models.py
import diffs
@diffs.register
class Question(models.Model):
question_text = models.CharField(max_length=200)
pub_date = models.DateTimeField('date published')
@diffs.register
class Choice(models.Model):
question = models.ForeignKey(Question, on_delete=models.CASCADE)
choice_text = models.CharField(max_length=200)
votes = models.IntegerField(default=0)
def get_diff_parent(self):
# save the db lookup
return Question(id=self.question_id)
question = Question.objects.create(question_text='What will happen?')
choice = Choice.objects.create(choice_text='Nothing', question=question)
choice.choice_text = 'Something'
choice.save()
# returns diffs for question and it's choices
len(question.diffs) # 3
نحوه نصب
نصب پکیج whl django-diffs-0.1.9:
pip install django-diffs-0.1.9.whl
نصب پکیج tar.gz django-diffs-0.1.9:
pip install django-diffs-0.1.9.tar.gz