Package: django-vff
django-vffIntroductionThis 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 atsettings.VFF_REPO_ROOT, or, if that is unset, at avf_reposubdirectory of django’ssettings.MEDIA_ROOT.Different VCSs can be used to manage the repository, using pluggable backends. The package only provides aGITbackend out of the box.InstallationInstall django-vff like you would install any other pypi package:$ pip install django-vffYou do not need to add anything into Django’sINSTALLED_APPS.ConfigurationYou have to set the following variables in django’ssettings.py:VFF_BACKENDA dotted name leading to a backend class, e.g."vff.git_backend.GitBackend". This setting is required.For the git backend:VFF_REPO_ROOTAbsolute path to the location of the git repository. This repository may or may not exist before setting up django-vff.VFF_REPO_PATHRelative 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_ROOTwill assume a value ofos.path.join(settings.MEDIA_ROOT, 'vf_repo'), andVFF_REPO_PATHwill assume a value of''.UsageYou use it like you would usedjango.db.models.FileField:from django.db import models
from vff.field import VersionedFileField


class MyModel(models.Model):
    name = models.CharField('Name', max_length=128)
    content = VersionedFileField(name='content', verbose_name='file content')Once you have an instance of theMyModelclass, 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 fileSaving and deletingAt the moment, saving and deleting has to be explicitly done for this field. So, for example, if you have a model instance with acontentvff field, and a view that uses an edit form with aforms.FileFieldfor it, after validating the form you would have to do something like: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()Likewise, when removing an instance, you would:username = request.user.username
commit_msg = u'entity removed'
instance.content.delete(username, commit_msg)
instance.delete()In the future, if there is interest, the package could include a special widget with input space for the necessary data (commit message, etc) so that saving and deleting would be transparent.Providing new backendsTo develop a new backend for django-vff, you have to subclass the abstract base classvff.abcs.VFFBackend. The methods that need to be implemented are documented in the docstrings of the class.CHANGES0.2b2 (2012-01-25)Fix typo on README.txtFix uncaught exception during initialization of GIT repository.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.