bw-file-resubmit 0.6.0rc2

Preserve files in Django forms during form validation errors. Drop-in replacement for django-file-resubmit

bw-file-resubmit

bw-file-resubmit is a drop-in replacement for django-file-resubmit, maintained by the BookWyrm project.

In a Django project you may have forms using FileField or ImageField. Everything works great, but when a ValidationError is raised, or you want to add some other check before finally submitting the form, you have to reselect all files and images again. This is because HTML <input type="file"> fields cannot be prepopulated with data due to basic browser security.

bw-file-resubmit solves this problem by caching the file and adding it again in the background. It works with FileField, ImageField and sorl.thumbnail.ImageField (see sorl-thumbnail).

How does it work?

Special widgets can be used to replace FileField and ImageField. When you submit files, every widget saves its file to the cache. When a ValidationError is raised, the widgets restore files from cache so the user doesn't have to upload them again.

• ResubmitFileWidget can be used in place of ClearableFileInput
• ResubmitImageWidget can be used in place of ClearableFileInput
• AdminResubmitImageWidget can be used in place of AdminFileWidget (Django) or AdminImageWidget (sorl-thumbnail)
• AdminResubmitMixin will apply the appropriate widget for all FileFields and ImageFields

Installation

pip install bw-file-resubmit

Configuration

Add "file_resubmit" to INSTALLED_APPS:

INSTALLED_APPS = {
    ...
    'file_resubmit',
    ...
}

Setup cache in settings.py:

CACHES = {
    'default': {
        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
    },
    "file_resubmit": {
        'BACKEND': 'django.core.cache.backends.filebased.FileBasedCache',
        "LOCATION": '/tmp/file_resubmit/'
    },
}

Examples

models.py

from django.db import models
from django.db.models import ImageField
# or if you use sorl-thumbnail:
from sorl.thumbnail.fields import ImageField

class Page(models.Model):
    title = models.CharField(max_length=100)
    content = models.TextField()
    image =  ImageField(upload_to='whatever1')

Form widgets

Ordinary form

forms.py

from django.forms import ModelForm
from file_resubmit.widgets import ResubmitImageWidget, ResubmitFileWidget
from .models import Page

class PageModelForm(forms.ModelForm)

    class Meta:
        model = MyModel
        widgets = {
            'picture': ResubmitImageWidget,
            'file': ResubmitFileWidget,
        }

class Book(forms.Form):
    form = PageModelForm

Admin form

admin.py

NOTE: admin.AdminResubmitFileWidget has been dropped from bw-file-resubmit. If you need to update a legacy django-file-resubmit project, use widgets.ResubmitFileWidget instead.

from django.forms import ModelForm
from file_resubmit.admin import AdminResubmitImageWidget,
from file_resubmit.widgets import ResubmitFileWidget
from .models import Page

class PageModelForm(forms.ModelForm)

    class Meta:
        model = MyModel
        widgets = {
            'picture': AdminResubmitImageWidget,
            'file': ResubmitFileWidget,
        }

class PageAdmin(admin.ModelAdmin):
    form = PageModelForm

admin.site.register(Page, PageAdmin)

Use as a model mixin in admin

admin.py

from django.contrib import admin
from file_resubmit.admin import AdminResubmitMixin
from .models import Page

class PageAdmin(AdminResubmitMixin, admin.ModelAdmin):
    pass

admin.site.register(Page, PageAdmin)

Licensing

bw-file-resubmit is free software under terms of the MIT License