python Django Mixins

Posted 2021-05-09

import json

from django.http import HttpResponse
from django.views.generic.edit import CreateView
from django.contrib.auth.decorators import user_passes_test
from django.utils.decorators import method_decorator


class StaffRequiredMixin(object):
    @method_decorator(user_passes_test(lambda u: u.is_staff))
    def dispatch(self, *args, **kwargs):
        return super(StaffRequiredMixin, self).dispatch(*args, **kwargs)


class SuperuserRequiredMixin(object):
    @method_decorator(user_passes_test(lambda u: u.is_superuser))
    def dispatch(self, *args, **kwargs):
        return super(SuperuserRequiredMixin, self).dispatch(*args, **kwargs)


class AjaxableResponseMixin(object):
    """
    Mixin to add AJAX support to a form.
    Must be used with an object-based FormView (e.g. CreateView)
    """
    def render_to_json_response(self, context, **response_kwargs):
        data = json.dumps(context)
        response_kwargs['content_type'] = 'application/json'
        return HttpResponse(data, **response_kwargs)

    def form_invalid(self, form):
        response = super(AjaxableResponseMixin, self).form_invalid(form)
        if self.request.is_ajax():
            return self.render_to_json_response(form.errors, status=400)
        else:
            return response

    def form_valid(self, form):
        # We make sure to call the parent's form_valid() method because
        # it might do some processing (in the case of CreateView, it will
        # call form.save() for example).
        response = super(AjaxableResponseMixin, self).form_valid(form)
        if self.request.is_ajax():
            data = {
                'pk': self.object.pk,
            }
            return self.render_to_json_response(data)
        else:
            return response


class AsDictionaryMixin:
    def to_dict(self):
        return {
            prop: self._represent(value)
            for prop, value in self.__dict__.items()
            if not self._is_internal(prop)
        }

    def _represent(self, value):
        if isinstance(value, object):
            if hasattr(value, 'to_dict'):
                return value.to_dict()
            else:
                return str(value)
        else:
            return value

    def _is_internal(self, prop):
        return prop.startswith('_')


class MultiRedirectMixin(object):
    """
    A mixin that supports submit-specific success redirection.
     Either specify one success_url, or provide dict with names of
     submit actions given in template as keys
     Example:
       In template:
         <input type="submit" name="create_new" value="Create"/>
         <input type="submit" name="delete" value="Delete"/>
       View:
         MyMultiSubmitView(MultiRedirectMixin, forms.FormView):
             success_urls = {"create_new": reverse_lazy('create'),
                               "delete": reverse_lazy('delete')}
    """
    success_urls = {}

    def form_valid(self, form):
        """ Form is valid: Pick the url and redirect.
        """

        for name in self.success_urls:
            if name in form.data:
                self.success_url = self.success_urls[name]
                break

        return HttpResponseRedirect(self.get_success_url())

    # def get_success_url(self):
    #     """
    #     Returns the supplied success URL.
    #     """
    #     if self.success_url:
    #         # Forcing possible reverse_lazy evaluation
    #         url = force_text(self.success_url)
    #     else:
    #         raise ImproperlyConfigured(
    #             _("No URL to redirect to. Provide a success_url."))
    #     return url