newforms: Implemented form_for_instance(). The resulting Form class does not yet have a method that saves the changes

git-svn-id: http://code.djangoproject.com/svn/django/trunk@4250 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/__init__.py

@@ -334,10 +334,10 @@ class Field(object):
             return self._choices
     choices = property(_get_choices)
 
-    def formfield(self):
+    def formfield(self, initial=None):
         "Returns a django.newforms.Field instance for this database Field."
         # TODO: This is just a temporary default during development.
-        return forms.CharField(required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.CharField(required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class AutoField(Field):
     empty_strings_allowed = False
@@ -375,7 +375,7 @@ class AutoField(Field):
         super(AutoField, self).contribute_to_class(cls, name)
         cls._meta.has_auto_field = True
 
-    def formfield(self):
+    def formfield(self, initial=None):
         return None
 
 class BooleanField(Field):
@@ -392,8 +392,8 @@ class BooleanField(Field):
     def get_manipulator_field_objs(self):
         return [oldforms.CheckboxField]
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.BooleanField(required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.BooleanField(required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class CharField(Field):
     def get_manipulator_field_objs(self):
@@ -409,8 +409,8 @@ class CharField(Field):
                 raise validators.ValidationError, gettext_lazy("This field cannot be null.")
         return str(value)
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.CharField(max_length=self.maxlength, required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.CharField(max_length=self.maxlength, required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 # TODO: Maybe move this into contrib, because it's specialized.
 class CommaSeparatedIntegerField(CharField):
@@ -483,8 +483,8 @@ class DateField(Field):
         val = self._get_val_from_obj(obj)
         return {self.attname: (val is not None and val.strftime("%Y-%m-%d") or '')}
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.DateField(required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.DateField(required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class DateTimeField(DateField):
     def to_python(self, value):
@@ -544,8 +544,8 @@ class DateTimeField(DateField):
         return {date_field: (val is not None and val.strftime("%Y-%m-%d") or ''),
                 time_field: (val is not None and val.strftime("%H:%M:%S") or '')}
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.DateTimeField(required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.DateTimeField(required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class EmailField(CharField):
     def __init__(self, *args, **kwargs):
@@ -561,8 +561,8 @@ class EmailField(CharField):
     def validate(self, field_data, all_data):
         validators.isValidEmail(field_data, all_data)
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.EmailField(required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.EmailField(required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class FileField(Field):
     def __init__(self, verbose_name=None, name=None, upload_to='', **kwargs):
@@ -696,8 +696,8 @@ class IntegerField(Field):
     def get_manipulator_field_objs(self):
         return [oldforms.IntegerField]
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.IntegerField(required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.IntegerField(required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class IPAddressField(Field):
     def __init__(self, *args, **kwargs):
@@ -793,8 +793,8 @@ class TimeField(Field):
         val = self._get_val_from_obj(obj)
         return {self.attname: (val is not None and val.strftime("%H:%M:%S") or '')}
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.TimeField(required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.TimeField(required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class URLField(Field):
     def __init__(self, verbose_name=None, name=None, verify_exists=True, **kwargs):
@@ -806,8 +806,8 @@ class URLField(Field):
     def get_manipulator_field_objs(self):
         return [oldforms.URLField]
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.URLField(required=not self.blank, verify_exists=self.verify_exists, label=capfirst(self.verbose_name))
+        return forms.URLField(required=not self.blank, verify_exists=self.verify_exists, label=capfirst(self.verbose_name), initial=initial)
 
 class USStateField(Field):
     def get_manipulator_field_objs(self):

django/db/models/fields/related.py

@@ -548,8 +548,8 @@ class ForeignKey(RelatedField, Field):
     def contribute_to_related_class(self, cls, related):
         setattr(cls, related.get_accessor_name(), ForeignRelatedObjectsDescriptor(related))
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.ChoiceField(choices=self.get_choices_default(), required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.ChoiceField(choices=self.get_choices_default(), required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class OneToOneField(RelatedField, IntegerField):
     def __init__(self, to, to_field=None, **kwargs):
@@ -612,8 +612,8 @@ class OneToOneField(RelatedField, IntegerField):
         if not cls._meta.one_to_one_field:
             cls._meta.one_to_one_field = self
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.ChoiceField(choices=self.get_choices_default(), required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.ChoiceField(choices=self.get_choices_default(), required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class ManyToManyField(RelatedField, Field):
     def __init__(self, to, **kwargs):
@@ -721,8 +721,8 @@ class ManyToManyField(RelatedField, Field):
     def set_attributes_from_rel(self):
         pass
 
-    def formfield(self):
+    def formfield(self, initial=None):
-        return forms.MultipleChoiceField(choices=self.get_choices_default(), required=not self.blank, label=capfirst(self.verbose_name))
+        return forms.MultipleChoiceField(choices=self.get_choices_default(), required=not self.blank, label=capfirst(self.verbose_name), initial=initial)
 
 class ManyToOneRel(object):
     def __init__(self, to, field_name, num_in_admin=3, min_num_in_admin=None,

django/newforms/models.py

@@ -5,10 +5,14 @@ and database field objects.
 
 from forms import BaseForm, DeclarativeFieldsMetaclass, SortedDictFromList
 
-__all__ = ('form_for_model', 'form_for_fields')
+__all__ = ('form_for_model', 'form_for_instance', 'form_for_fields')
 
 def create(self, save=True):
-    "Creates and returns model instance according to self.clean_data."
+    """
+    Creates and returns model instance according to self.clean_data.
+
+    This method is created for any form_for_model Form.
+    """
     if self.errors:
         raise ValueError("The %s could not be created because the data didn't validate." % self._model._meta.object_name)
     obj = self._model(**self.clean_data)
@@ -16,7 +20,7 @@ def create(self, save=True):
         obj.save()
     return obj
 
-def form_for_model(model, form=None):
+def form_for_model(model, form=BaseForm):
     """
     Returns a Form class for the given Django model class.
 
@@ -29,9 +33,25 @@ def form_for_model(model, form=None):
         if formfield:
             field_list.append((f.name, formfield))
     fields = SortedDictFromList(field_list)
-    form = form or BaseForm
     return type(opts.object_name + 'Form', (form,), {'fields': fields, '_model': model, 'create': create})
 
+def form_for_instance(instance, form=BaseForm):
+    """
+    Returns a Form class for the given Django model instance.
+
+    Provide 'form' if you want to use a custom BaseForm subclass.
+    """
+    model = instance.__class__
+    opts = model._meta
+    field_list = []
+    for f in opts.fields + opts.many_to_many:
+        current_value = getattr(instance, f.attname)
+        formfield = f.formfield(initial=current_value)
+        if formfield:
+            field_list.append((f.name, formfield))
+    fields = SortedDictFromList(field_list)
+    return type(opts.object_name + 'InstanceForm', (form,), {'fields': fields, '_model': model})
+
 def form_for_fields(field_list):
     "Returns a Form class for the given list of Django database field instances."
     fields = SortedDictFromList([(f.name, f.formfield()) for f in field_list])

tests/modeltests/model_forms/models.py

@@ -36,7 +36,7 @@ class Article(models.Model):
         return self.headline
 
 __test__ = {'API_TESTS': """
->>> from django.newforms import form_for_model, BaseForm
+>>> from django.newforms import form_for_model, form_for_instance, BaseForm
 
 >>> Category.objects.all()
 []
@@ -141,4 +141,13 @@ subclass of BaseForm, not Form.
 >>> f = CategoryForm()
 >>> f.say_hello()
 hello
+
+Use form_for_instance to create a Form from a model instance. The difference
+between this Form and one created via form_for_model is that the object's
+current values are inserted as 'initial' data in each Field.
+>>> w = Writer.objects.get(name='Mike Royko')
+>>> RoykoForm = form_for_instance(w)
+>>> f = RoykoForm(auto_id=False)
+>>> print f
+<tr><th>Name:</th><td><input type="text" name="name" value="Mike Royko" maxlength="50" /></td></tr>
 """}