52 lines
2.1 KiB
Python
52 lines
2.1 KiB
Python
from django import forms
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from form_utils.widgets import ClearableFileInput
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class FakeEmptyFieldFile(object):
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"""
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A fake FieldFile that will convice a FileField model field to
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actually replace an existing file name with an empty string.
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FileField.save_form_data only overwrites its instance data if the
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incoming form data evaluates to True in a boolean context (because
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an empty file input is assumed to mean "no change"). We want to be
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able to clear it without requiring the use of a model FileField
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subclass (keeping things at the form level only). In order to do
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this we need our form field to return a value that evaluates to
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True in a boolean context, but to the empty string when coerced to
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unicode. This object fulfills that requirement.
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It also needs the _committed attribute to satisfy the test in
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FileField.pre_save.
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This is, of course, hacky and fragile, and depends on internal
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knowledge of the FileField and FieldFile classes. But it will
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serve until Django FileFields acquire a native ability to be
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cleared (ticket 7048).
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"""
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def __unicode__(self):
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return u''
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_committed = True
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class ClearableFileField(forms.MultiValueField):
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default_file_field_class = forms.FileField
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widget = ClearableFileInput
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def __init__(self, file_field=None, template=None, *args, **kwargs):
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file_field = file_field or self.default_file_field_class(*args,
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**kwargs)
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fields = (file_field, forms.BooleanField(required=False))
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kwargs['required'] = file_field.required
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kwargs['widget'] = self.widget(file_widget=file_field.widget,
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template=template)
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super(ClearableFileField, self).__init__(fields, *args, **kwargs)
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def compress(self, data_list):
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if data_list[1] and not data_list[0]:
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return FakeEmptyFieldFile()
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return data_list[0]
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class ClearableImageField(ClearableFileField):
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default_file_field_class = forms.ImageField
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