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How to disable auto strip in Charfield in Django

·2 mins

In Django, when edit field in admin page or post data to forms, the leading and tailing whitespace in CharField and TextField are removed.

The reason is strip=True parameter in forms.CharField, which is added in Djagno 1.9. You can see the discussion in django tiket #4960 and here is source code. models.CharField and models.TextField use formfield() to create form to interact with user, then both of them eventually create a forms.CharField

It only affect the value return from forms, you can still update model manually and calling save() to save it with spaces.

Normally, this feature help us to keep text field clean. But sometimes you may want to get the original value, and here are three different solutions:

Suppose we have this Test model.

class Test(models.Model):
    char = models.CharField(max_length=20)
    text = models.TextField()

Change ModelAdmin #

    def formfield_for_dbfield(self, db_field, request, **kwargs):
        if in ['char', 'text']:
            kwargs['strip'] = False
        return super().formfield_for_dbfield(db_field, request, **kwargs)

This method tackles the problem by overriding fields’ default fromfiled method.

Define Custom Form #

class CustomForm(forms.ModelForm):
    char = forms.CharField(strip=False)
    text = forms.CharField(strip=False, widget=forms.Textarea)

    class Meta:
        model = Test
        exclude = []

    form = CustomForm

Now when edit data in admin panel, the whitespace is not removed anymore.

Use Custom Field #

You can also use your custom field in For example:

from django.db.models import TextField

class NonStrippingTextField(TextField):
    def formfield(self, **kwargs):
        kwargs['strip'] = False
        return super(NonStrippingTextField, self).formfield(**kwargs)

class Test(models.Model):
    text = NonStrippingTextField()


REST Framework #

If you use Django REST framework to edit data, you only need to change the serializer.

class TestSerializer(serializers.HyperlinkedModelSerializer):
    class Meta:
        model = Test
        fields = '__all__'
        extra_kwargs = {"char": {"trim_whitespace": False},
                        "text": {"trim_whitespace": False}}

Ref #

  1. StackOverflow - Django TextField and CharField is stripping spaces and blank lines
  2. Djanog - TextField constructor needs a strip=False option
  3. StackOverflow - In Django REST control serializer does not automatically remove spaces
  4. Allow Whitespace to be a Valid CharField Value in Django Admin