Refs #131 -- Add exporter to download invoices

src/pretix/base/exporters/__init__.py

@@ -1,2 +1,3 @@
+from .invoices import *  # noqa
 from .json import *  # noqa
 from .mail import *  # noqa

src/pretix/base/exporters/invoices.py

@@ -0,0 +1,31 @@
+import os
+import tempfile
+from zipfile import ZipFile
+
+from django.dispatch import receiver
+from django.utils.translation import ugettext as _
+
+from ..exporter import BaseExporter
+from ..models import Invoice
+from ..signals import register_data_exporters
+
+
+class InvoiceExporter(BaseExporter):
+    identifier = 'invoices'
+    verbose_name = _('All invoices')
+
+    def render(self, form_data: dict):
+        with tempfile.TemporaryDirectory() as d:
+            with ZipFile(os.path.join(d, 'tmp.zip'), 'w') as zipf:
+                for i in self.event.invoices.all():
+                    i.file.open('r')
+                    zipf.writestr('{}.pdf'.format(i.number), i.file.read())
+                    i.file.close()
+
+            with open(os.path.join(d, 'tmp.zip'), 'rb') as zipf:
+                return 'invoices.zip', 'application/zip', zipf.read()
+
+
+@receiver(register_data_exporters, dispatch_uid="exporter_invoices")
+def register_invoice_export(sender, **kwargs):
+    return InvoiceExporter