Form and View mixins for HTMX/partials

src/servala/frontend/forms/mixins.py

@@ -0,0 +1,15 @@
+class HtmxMixin:
+    """
+    Form mixin that retains only a single field when specified.
+    Useful when sending single fields with htmx.
+    """
+
+    def __init__(self, *args, **kwargs):
+        self.single_field = kwargs.pop("single_field", None)
+
+        super().__init__(*args, **kwargs)
+
+        if self.single_field and self.single_field in self.fields:
+            field = self.fields[self.single_field]
+            self.fields.clear()
+            self.fields[self.single_field] = field

src/servala/frontend/views/mixins.py

@@ -0,0 +1,36 @@
+from django.utils.functional import cached_property
+from django.views.generic import TemplateView
+
+
+class HtmxMixin(TemplateView):
+    fragments = []
+
+    @cached_property
+    def is_htmx(self):
+        return self.request.headers.get("HX-Request")
+
+    def _get_fragment(self):
+        if self.request.method == "POST":
+            fragment = self.request.POST.get("fragment")
+        else:
+            fragment = self.request.GET.get("fragment")
+        if fragment and fragment in self.fragments:
+            return fragment
+
+    def get_template_names(self):
+        template_names = super().get_template_names()
+        if self.is_htmx and (fragment := self._get_fragment()):
+            return [f"{template_names[0]}#{fragment}"]
+        return template_names
+
+    def get_form_kwargs(self):
+        result = super().get_form_kwargs()
+        if self.is_htmx and (field_name := self.request.POST.get("hx-single-field")):
+            result["single_field"] = field_name
+        return result
+
+    def form_valid(self, form):
+        result = super().form_valid(form)
+        if self.is_htmx and self._get_fragment():
+            return self.get(self.request, *self.args, **self.kwargs)
+        return result