django-immutablefield 0.1.1

django-immutablefield is inspired by a Google search that didn't turn up a reusable solution for making fields immutable inside of a Django model.<br /><br />Installing<br /><br />One of the following:<br /><br />Via the ole' standby:<br /><br />easy_install django-immutablefield<br /><br />Pip:<br /><br />pip install django-immutablefield<br /><br />To install directly from Bitbucket:<br /><br />pip install -e hg+http://bitbucket.org/robmadole/django-immutablefield#egg=django-immutablefield<br /><br />Hint<br /><br />You do not need to add anything into Django's INSTALLED_APPS<br /><br />What does it do<br /><br />Allows you to define certain fields as immutable inside of Django models.<br /><br />It works as a drop-in replacement for Django's own Model. This means you can ImmutableModel even if you don't specify ImmutableMeta.<br /><br />from django.db import models<br /><br />from immutablefield.models import ImmutableModel<br /><br />CruiseShip(ImmutableModel):<br /> name = models.CharField(max_length=50)<br /><br /> class ImmutableMeta:<br /> # After ya name a ship, you can't change it matey<br /> immutable = ['name']<br /><br /> def __unicode__(self):<br /> return u'%s' % self.name<br /><br />Now you can try with all your might, but the field won't change (within reason, sure this is Python we can do almost anything if we try hard enough)<br /><br />>>> queen_anne = CruiseShip.objects.create(name='Queen Anne')<br />< CruiseShip 'Queen Anne' ><br />>>> queen_anne.name = 'King George'<br />>>> queen_anne.name<br />'Queen Anne'<br /><br />You can make it complain<br /><br />Change the meta section to include quiet = False and it will raise a ValueError if an attempt is made to change this value<br /><br />class ImmutableMeta:<br /> # After ya name a ship, you can't change it matey<br /> immutable = ['name']<br /> quiet = False<br /><br />The error is raised as soon as you try and set the field, not when save() is called.<br /><br />>>> queen_anne = CruiseShip.objects.create(name='Queen Anne')<br />< CruiseShip 'Queen Anne'><br />>>> queen_anne.name = 'King George'<br />ValueError: name is immutable and cannot be changed<br /><br />Reference<br /><br />ImmutableMeta<br /><br /> Specify options that control how immutable fields are handled when subclassing the ImmutableModel class<br /><br /> immutable<br /><br /> Tell ImmutableModel which fields should not be allowed to change. This value must be a tuple or a list and contain the names of the fields as strings.:<br /><br /> class ImmutableMeta:<br /> immutable = ['my_special_id']<br /><br /> Specify multiple fields:<br /><br /> class ImmutableMeta:<br /> immutable = ['my_special_id', 'name', 'foreign_key']<br /><br /> quiet<br /><br /> If an attempt is made to change an immutable field, should we quietly prevent it.<br /><br /> Set this value to False to raise a ValueError when an immutable field is changed.:<br /><br /> class ImmutableMeta:<br /> immutable = ['my_special_id']<br /> quiet = False<br /><br />#md5=0701e924aa82265790cc72d1bbc4762b

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Platforms:	*nix, Linux
Keyword:	039name039,  Anne,  Can039t,  Change,  Class,  Django,  Django Immutablefield,  False,  Field,  Fields,  Immutable,  Immutablefield,  Immutablemeta,  Immutablemodel,  Install,  Matey,  Quiet,  Special,  Valueerror
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