contrib/cowell/forms.py

   1 from django.forms.models import ModelFormMetaclass, ModelForm
   2 from django.utils.datastructures import SortedDict
   3 from philo.utils import fattr
   4
   5
   6 __all__ = ('ProxyFieldForm',)
   7
   8
   9 def proxy_fields_for_entity_model(entity_model, fields=None, exclude=None, widgets=None, formfield_callback=lambda f, **kwargs: f.formfield(**kwargs)):
  10         field_list = []
  11         ignored = []
  12         opts = entity_model._entity_meta
  13         for f in opts.proxy_fields:
  14                 if not f.editable:
  15                         continue
  16                 if fields and not f.name in fields:
  17                         continue
  18                 if exclude and f.name in exclude:
  19                         continue
  20                 if widgets and f.name in widgets:
  21                         kwargs = {'widget': widgets[f.name]}
  22                 else:
  23                         kwargs = {}
  24                 formfield = formfield_callback(f, **kwargs)
  25                 if formfield:
  26                         field_list.append((f.name, formfield))
  27                 else:
  28                         ignored.append(f.name)
  29         field_dict = SortedDict(field_list)
  30         if fields:
  31                 field_dict = SortedDict(
  32                         [(f, field_dict.get(f)) for f in fields
  33                                 if ((not exclude) or (exclude and f not in exclude)) and (f not in ignored) and (f in field_dict)]
  34                 )
  35         return field_dict
  36
  37
  38 # BEGIN HACK - This will not be required after http://code.djangoproject.com/ticket/14082 has been resolved
  39
  40 class ProxyFieldFormBase(ModelForm):
  41         pass
  42
  43 _old_metaclass_new = ModelFormMetaclass.__new__
  44
  45 def _new_metaclass_new(cls, name, bases, attrs):
  46         formfield_callback = attrs.get('formfield_callback', lambda f, **kwargs: f.formfield(**kwargs))
  47         new_class = _old_metaclass_new(cls, name, bases, attrs)
  48         opts = new_class._meta
  49         if issubclass(new_class, ProxyFieldFormBase) and opts.model:
  50                 # "override" proxy fields with declared fields by excluding them if there's a name conflict.
  51                 exclude = (list(opts.exclude or []) + new_class.declared_fields.keys()) or None
  52                 proxy_fields = proxy_fields_for_entity_model(opts.model, opts.fields, exclude, opts.widgets, formfield_callback) # don't pass in formfield_callback
  53                 new_class.proxy_fields = proxy_fields
  54                 new_class.base_fields.update(proxy_fields)
  55         return new_class
  56
  57 ModelFormMetaclass.__new__ = staticmethod(_new_metaclass_new)
  58
  59 # END HACK
  60
  61
  62 class ProxyFieldForm(ProxyFieldFormBase): # Would inherit from ModelForm directly if it weren't for the above HACK
  63         def __init__(self, *args, **kwargs):
  64                 initial = kwargs.pop('initial', None)
  65                 instance = kwargs.get('instance', None)
  66                 if instance is not None:
  67                         new_initial = {}
  68                         for f in instance._entity_meta.proxy_fields:
  69                                 if self._meta.fields and not f.name in self._meta.fields:
  70                                         continue
  71                                 if self._meta.exclude and f.name in self._meta.exclude:
  72                                         continue
  73                                 new_initial[f.name] = f.value_from_object(instance)
  74                 else:
  75                         new_initial = {}
  76                 if initial is not None:
  77                         new_initial.update(initial)
  78                 kwargs['initial'] = new_initial
  79                 super(ProxyFieldForm, self).__init__(*args, **kwargs)
  80
  81         @fattr(alters_data=True)
  82         def save(self, commit=True):
  83                 cleaned_data = self.cleaned_data
  84                 instance = super(ProxyFieldForm, self).save(commit=False)
  85
  86                 for f in instance._entity_meta.proxy_fields:
  87                         if not f.editable or not f.name in cleaned_data:
  88                                 continue
  89                         if self._meta.fields and f.name not in self._meta.fields:
  90                                 continue
  91                         if self._meta.exclude and f.name in self._meta.exclude:
  92                                 continue
  93                         setattr(instance, f.attname, cleaned_data[f.name])
  94
  95                 if commit:
  96                         instance.save()
  97                         self.save_m2m()
  98
  99                 return instance