django-vff 0.2b1

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 at settings.VFF_REPO_ROOT, or, if that is unset, at a vf_repo 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:

VFF_BACKEND

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

For the git backend:

VFF_REPO_ROOT

Absolute path to the location of the git repository. This repository may or may not exist before setting up django-vff.

VFF_REPO_PATH

Relative path within the git repository to the directory where django-vff keeps its managed files.

If these two settings for the git backend are not set, VFF_REPO_ROOT will assume a value of os.path.join(settings.MEDIA_ROOT, 'vf_repo'), and VFF_REPO_PATH will assume a value of ''.

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

name = instance.content.name
content = form['content'].data
username = request.user.username
commit_msg = form['commit_msg'].data.encode('utf8')
instance.content.save(name, content, username, commit_msg)
instance.save()

username = request.user.username
commit_msg = u'entity removed'
instance.content.delete(username, commit_msg)
instance.delete()

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 documented in the docstrings of the class.

0.2b1 (2012-01-24)

• The (git) repo can now be anywhere in the filesystem (not necessarily inside the MEDIA_ROOT), and django-vff can be told to keep its files in a subdirectory iof the repo.

0.1b4 (2011-10-01)

• Better fix for error when deleting objects with no file in the repo.

0.1b3 (2011-10-01)

• Do not fail deleting objects with no file in the repo.

0.1b2 (2011-09-20)

• Remove the files from the repository when deleting objects.

• Change the signature of VersionedFieldFile’s save and delete so they are compatible with django’s FieldFile.

0.1b1 (2011-09-02)

• Initial version which includes a VersionedFileField and a git backend.