uncloud/uncloud_pay/admin.py

from django.contrib import admin
from django.template.response import TemplateResponse
from django.urls import path
from django.conf.urls import url

from uncloud_pay.views import BillViewSet
from hardcopy import bytestring_to_pdf
from django.core.files.temp import NamedTemporaryFile
from django.http import FileResponse
from django.template.loader import render_to_string


from uncloud_pay.models import Bill, Order, BillRecord, BillingAddress


class BillRecordInline(admin.TabularInline):
#    model = Bill.bill_records.through
    model = BillRecord

# AT some point in the future: expose REPLACED and orders that depend on us
# class OrderInline(admin.TabularInline):
#     model = Order
#     fk_name = "replaces"
# class OrderAdmin(admin.ModelAdmin):
#     inlines = [ OrderInline ]

class BillAdmin(admin.ModelAdmin):
    inlines = [ BillRecordInline ]

    def get_urls(self):
        """
        Create URLs for PDF view
        """

        info = "%s_%s" % (self.model._meta.app_label, self.model._meta.model_name)
        pat = lambda regex, fn: url(regex, self.admin_site.admin_view(fn), name='%s_%s' % (info, fn.__name__))

        url_patterns = [
            pat(r'^([0-9]+)/as_pdf/$', self.my_view),
        ] + super().get_urls()

        return url_patterns

    def my_view(self, request, object_id):
        bill = self.get_object(request, object_id=object_id)
        print(bill)

        if bill is None:
            raise self._get_404_exception(object_id)

        output_file = NamedTemporaryFile()
        bill_html = render_to_string("bill.html.j2", {'bill': bill,
                                                      'bill_records': bill.billrecord_set.all()
        })

        bytestring_to_pdf(bill_html.encode('utf-8'), output_file)
        response = FileResponse(output_file, content_type="application/pdf")
        response['Content-Disposition'] = f'filename="bill_{bill}.pdf"'

        return response

        # ...
        context = dict(
           # Include common variables for rendering the admin template.
           self.admin_site.each_context(request),
           # Anything else you want in the context...
#           key=value,
        )

        #return TemplateResponse(request, "admin/change_list.html", context)


admin.site.register(Bill, BillAdmin)
admin.site.register(Order)
admin.site.register(BillRecord)
admin.site.register(BillingAddress)


#admin.site.register(Order, OrderAdmin)