django-vff 0.1b1

Introduction

This package offers a file field for django models, that stores the file contents under a VCS (version control system). Everytime a field of this type is changed for a particular model instance, the new content will be commited as a new version in the repository. Thus, there will be one file in the repository for each vff field and instance. The repository will be a subdirectory of django’s settings.MEDIA_ROOT.

Different VCSs can be used to manage the repository, using pluggable backends. The package only provides a GIT backend out of the box.

Installation

Install django-vff like you would install any other pypi package:

$ pip install django-vff

You do not need to add anything into Django’s INSTALLED_APPS.

Configuration

You have to set the following variables in django’s settings.py:

VERSIONEDFILE_BACKEND

A dotted name leading to a backend class, e.g. "vff.git_backend.GitBackend".

Usage

You use it like you would use django.db.models.FileField:

from django.db import models
from vff.field import VersionedFileField


class MyModel(models.model):
    name = models.CharField('Name')
    content = VersionedFileField(name='content', verbose_name='file content')

Once you have an instance of the MyModel class, you can use three special methods to list available versions, to get specific versions, and to get diffs between versions:

• list revisions:

  >>> revs = instance.content.list_revisions()
  >>> from pprint import pprint
  >>> pprint(revs)
  [{'author': u'John Smith',
    'date': datetime.datetime(2011, 6, 16, 13, 25, 30),
    'message': u'second version',
    'versionid': 'a64ea785e195bbf4b3064e6701adbdbf4b5d13be'},
   {'author': u'Martha Brown',
    'date': datetime.datetime(2011, 6, 16, 8, 24, 36),
    'message': u'first version',
    'versionid': '048848a70205d0e18d836f403e2a02830492cbf9'}]

• get the string content of a specific revision:

  >>> rev1_id = revs[-1]['versionid']
  >>> instance.content.get_revision(rev1_id)
  u'These are the contents of the first version of the file'

• get the diff between two revisions:

  >>> rev2_id = revs[-2]['versionid']
  >>> print instance.content.get_diff(rev1_id, rev2_id)
  --- 048848a70205d0e18d836f403e2a02830492cbf9
  
  +++ a64ea785e195bbf4b3064e6701adbdbf4b5d13be
  
  @@ -1,1 +1,1 @@
  
  -These are the contents of the first version of the file
  +These are the contents of the second version of the file

Providing new backends

To develop a new backend for django-vff, you have to subclass the abstract base class vff.abcs.VFFBackend. The methods that need to be implemented are well documented in the docstrings of the class.