Autocomplete fields

To add autocomplete functionality to ModelChoiceField and ModelMultipleChoiceField, use UnfoldAdminAutocompleteModelChoiceField and UnfoldAdminMultipleAutocompleteModelChoiceField.

Steps to create autocomplete fields

• Start by creating a custom view that subclasses BaseAutocompleteView and returns a JSON response containing the available select options. Be sure to perform all necessary permission checks within this view to control user access to the data.
• Next, register each custom view as a URL in your ModelAdmin class using the custom_urls attribute.
• Finally, in your custom form fields, set the url_path to the URL pattern name that points to your custom autocomplete view.

from django import forms
from django.contrib import admin
from django.utils.translation import gettext_lazy as _

from unfold.admin import ModelAdmin
from unfold.views import BaseAutocompleteView
from unfold.fields import (
    UnfoldAdminAutocompleteModelChoiceField,
    UnfoldAdminMultipleAutocompleteModelChoiceField,
)

from .models import MyModel

# Custom ListView returning JSON with available select options
class MyAutocompleteView(BaseAutocompleteView):
    model = MyModel

    def dispatch(self, request, *args, **kwargs):
        # Permissions checks here
        return super().dispatch(request, *args, **kwargs)

    def get_queryset(self):
        # Search query is available in the request.GET object under the key "term"
        term = self.request.GET.get("term")

        # Additional filters and permissions checks here
        qs = super().get_queryset()

        # No search provided, return all results
        if term == "":
            return qs

        # Search query provided, filter results
        return qs.filter(my_field__icontains=term)


@admin.register(MyModel)
class MyModelAdmin(ModelAdmin):
    # Register custom ListView above
    custom_urls = (
        (
            "autocomplete-url-path",
            "custom_autocomplete_path_name",
            MyAutocompleteView.as_view()
        ),
    )

class MyForm(forms.Form):
    one_object = UnfoldAdminAutocompleteModelChoiceField(
        label=_("Object - Single value"),
        # Important for validation. Make sure it offers same results as the custom view
        queryset=MyModel.objects.all(),
        # Map autocomplete results to the custom view
        url_path="admin:custom_autocomplete_path_name",
    )
    multiple_objects = UnfoldAdminMultipleAutocompleteModelChoiceField(
        label=_("Objects - Multiple values"),
        queryset=MyModel.objects.all(),
        url_path="admin:custon_autocomplete_path_name",
    )

SQL query optimisation

When using UnfoldAdminAutocompleteModelChoiceField, the ModelChoiceField is initialized with the full queryset on page load, which generates a complete list of choices. This can be problematic if your database table contains a large number of records. To address this, you can override the queryset with an empty queryset during GET requests. For POST requests, you should update the queryset to include only the selected choices. This approach optimizes performance by loading only the necessary data.

class MyAutocompleteView(BaseAutocompleteView):
    one_object = UnfoldAdminAutocompleteModelChoiceField(
        label=_("Object - Single value"),
        queryset=MyModel.objects.all(),
        url_path="admin:custom_autocomplete_path_name",
    )

    def __init__(self, request, *args, **kwargs):
        # The request argument needs to be manually passed. If you are using
        # `FormView` just use `get_form_kwargs` to pass the request argument.

        if request.method == "GET":
            if "initial" in kwargs:
                # Initial values are present
                self.queryset = MyModel.objects.filter(pk__in=kwargs["initial"]
            else:

                self.queryset = MyModel.objects.none()
        elif request.method == "POST":
            self.queryset = MyModel.objects.filter(pk__in=request.POST.getlist("objects"))

        super().__init__(request, *args, **kwargs)