Simon Willison’s Weblog

10th April 2025 - Link Blog

Django: what’s new in 5.2. Adam Johnson provides extremely detailed unofficial annotated release notes for the latest Django.

I found his explanation and example of Form BoundField customization particularly useful - here's the new pattern for customizing the class= attribute on the label associated with a CharField:

from django import forms

class WideLabelBoundField(forms.BoundField):
    def label_tag(self, contents=None, attrs=None, label_suffix=None):
        if attrs is None:
            attrs = {}
        attrs["class"] = "wide"
        return super().label_tag(contents, attrs, label_suffix)

class NebulaForm(forms.Form):
    name = forms.CharField(
        max_length=100,
        label="Nebula Name",
        bound_field_class=WideLabelBoundField,
    )

I'd also missed the new HttpResponse.get_preferred_type() method for implementing HTTP content negotiation:

content_type = request.get_preferred_type(
    ["text/html", "application/json"]
)