Source code for htmx_views.widgets

# -*- coding: utf-8 -*-
"""Create an htmx backed linked select widget."""

# Python imports
from urllib.parse import urlencode

# Django imports
from django.core.exceptions import ImproperlyConfigured
from django.forms.widgets import Select
from django.urls import reverse_lazy
from django.utils.text import format_lazy

# app imports
from ._optional import get_ajax_select_registry

registry = get_ajax_select_registry()




class HTMXSelectWidget(Select):
    """Override SelectWidget to allow the options to be updated on a linked change.

    This uses the machinery of django-ajax-select lookups to derive the list of options,
    but uses htmx for the transfer mechanism.
    """

    # temmplate_name = "htmx_views/widgets/select.html"

    def __init__(self, lookup_channel, parent=None, *args, **kwargs):
        """Extract linked Select.

        Args:
            lookup_channel (str):
                The name of an ajax_select lookup channel
        """
        try:
            self.lookup = registry.get(lookup_channel)
        except ImproperlyConfigured as error:
            raise ImproperlyConfigured(
                f"Attempting to use a htmx_views widget with lookup channel {lookup_channel} that does not exist."
            ) from error

        self.lookup_channel = lookup_channel
        if parent is None:
            parent = getattr(self.lookup, "parameter_name", None)
        if parent is None:
            raise ImproperlyConfigured(
                f"Creating an htmx_views widget for {lookup_channel} without knowing the trigger."
            )
        self.parent_name = parent
        endpoint = reverse_lazy("htmx_views:select", args=(self.lookup_channel,))
        query_string = urlencode({"_htmx_parent": self.parent_name})
        attrs = dict(kwargs.pop("attrs", {}))
        attrs.update(
            {
                "hx-get": format_lazy("{}?{}", endpoint, query_string),
                "hx-trigger": f"change from:#id_{self.parent_name}",
                "hx-include": f"#id_{self.parent_name}",
            }
        )
        kwargs["attrs"] = attrs

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



    def get_context(self, name, value, attrs):
        """Customise the context."""
        attrs = dict(attrs or {})
        attrs["hx-target"] = f"#id_{name}"
        return super().get_context(name, value, attrs)