Django admin action ith an intermidiate page with form example (this one uses django-push-notifications)

admin.py

class ExtendedDeviceAdmin(DeviceAdmin):
    actions = ("send_message", "send_bulk_message", "send_custom_message_bulk", "enable", "disable")

    def send_custom_message_bulk(self, request, queryset):

        form = None

        # TODO: handle situation when results from multiple pages selected (or is it handled automatically in django 2?)
        if 'apply' in request.POST:  # if user pressed 'apply' on intermediate page

            form = CustomPushMessageAdminForm(request.POST)

            if form.is_valid():

                message = form.cleaned_data['alert_body']

                # check if alert body is a json and convert it to dict if it is
                # if it's not, just leave it as a string
                try:
                    message = json.loads(message)
                except json.JSONDecodeError:
                    pass

                extra = None

                extra = form.extra_json
                try:
                    extra = json.loads(extra)
                except json.JSONDecodeError:
                    pass
                
                # calls some actual method doing heavy work
                self.send_messages(request, queryset, True, message_text=message, extra=extra)

                # Show alert that everything is cool
                self.message_user(request, "Sent custom messages")

                # Return to previous page
                # return None
                return HttpResponseRedirect(request.get_full_path())

        if not form:
            form = CustomPushMessageAdminForm(initial={'_selected_action': queryset.values_list('id', flat=True)})

        return render(request, "admin/custom_push_message.html", {'items': queryset, 'form': form})

custom_push_message.html

{% extends "admin/base_site.html" %}
{% load i18n static %}

{% block extrastyle %}{{ block.super }}<link rel="stylesheet" type="text/css" href="{% static "admin/css/dashboard.css" %}">
{{ form.media }}
{% endblock %}

{% block coltype %}colMS{% endblock %}

{% block bodyclass %}{{ block.super }} dashboard{% endblock %}

{% block breadcrumbs %}{% endblock %}

{% block content %}
<div id="content-main">
<h1>Push notification structure</h1>
<form method="post" action="">
    {% csrf_token %}
    {{ form.as_p }}
  
    <input type="hidden" name="action" value="send_custom_message_bulk" />
  
    <p>
        <input type="submit" name="apply" value="apply"/>
    </p>
</form>

</div>

{% endblock %}