Django : customizing FileField value while editing a model

Question

I\'ve got a model, with FileField. When I edit this model in a view, I want to change the \"current\" value of FileField which gets displayed in the vi

Answer 1

Django 1.10.x or older version

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The easiest way is to override the template_substitution_values in default ClearableFileInput django widget that will be used later in rendering the form. This is a much cleaner approach that does not result in any unnecessary code duplication.

from os import path
from django.forms.widgets import ClearableFileInput
from django.utils.html import conditional_escape

class CustomClearableFileInput(ClearableFileInput):
    def get_template_substitution_values(self, value):
        """
        Return value-related substitutions.
        """
        return {
            'initial': conditional_escape(path.basename(value.name)),
            'initial_url': conditional_escape(value.url),
        }

then use the widget in forms.py as follow:

class DemoVar_addform(ModelForm):
    Welcome_sound = forms.FileField(widget=CustomClearableFileInput)    
    ...

    class Meta:
        model = DemoVar_model

    ...

Django 1.11.x or later versions

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Check ImageField / FileField Django form Currently unable to trim the path to filename.