Add badge printing capabilities (#868)

Add badge printing capabilities

src/pretix/plugins/badges/exporters.py

@@ -0,0 +1,103 @@
+import json
+from collections import OrderedDict
+from io import BytesIO
+from typing import Tuple
+
+from django import forms
+from django.contrib.staticfiles import finders
+from django.core.files import File
+from django.core.files.base import ContentFile
+from django.core.files.storage import default_storage
+from django.utils.translation import ugettext as _
+from PyPDF2 import PdfFileMerger
+from reportlab.lib import pagesizes
+from reportlab.pdfgen import canvas
+
+from pretix.base.exporter import BaseExporter
+from pretix.base.i18n import language
+from pretix.base.models import Order, OrderPosition
+from pretix.base.pdf import Renderer
+from pretix.plugins.badges.models import BadgeItem, BadgeLayout
+
+
+def _renderer(event, layout):
+    if isinstance(layout.background, File) and layout.background.name:
+        bgf = default_storage.open(layout.background.name, "rb")
+    else:
+        bgf = open(finders.find('pretixplugins/badges/badge_default_a6l.pdf'), "rb")
+    return Renderer(event, json.loads(layout.layout), bgf)
+
+
+def render_pdf(event, positions):
+    Renderer._register_fonts()
+
+    renderermap = {
+        bi.item_id: _renderer(event, bi.layout)
+        for bi in BadgeItem.objects.select_related('layout').filter(item__event=event)
+    }
+    try:
+        default_renderer = _renderer(event, event.badge_layouts.get(default=True))
+    except BadgeLayout.DoesNotExist:
+        default_renderer = None
+    merger = PdfFileMerger()
+
+    for op in positions:
+        r = renderermap.get(op.item_id, default_renderer)
+        if not r:
+            continue
+
+        with language(op.order.locale):
+            buffer = BytesIO()
+            p = canvas.Canvas(buffer, pagesize=pagesizes.A4)
+            r.draw_page(p, op.order, op)
+            p.save()
+            outbuffer = r.render_background(buffer, 'Badge')
+            merger.append(ContentFile(outbuffer.read()))
+
+    outbuffer = BytesIO()
+    merger.write(outbuffer)
+    merger.close()
+    outbuffer.seek(0)
+    return outbuffer
+
+
+class BadgeExporter(BaseExporter):
+    identifier = "badges"
+    verbose_name = _("Attendee badges")
+
+    @property
+    def export_form_fields(self):
+        d = OrderedDict(
+            [
+                ('items',
+                 forms.ModelMultipleChoiceField(
+                     queryset=self.event.items.all(),
+                     label=_('Limit to products'),
+                     widget=forms.CheckboxSelectMultiple(
+                         attrs={'class': 'scrolling-multiple-choice'}
+                     ),
+                     initial=self.event.items.filter(admission=True)
+                 )),
+                ('include_pending',
+                 forms.BooleanField(
+                     label=_('Include pending orders'),
+                     required=False
+                 )),
+            ]
+        )
+        return d
+
+    def render(self, form_data: dict) -> Tuple[str, str, str]:
+        qs = OrderPosition.objects.filter(
+            order__event=self.event, item_id__in=form_data['items']
+        ).prefetch_related(
+            'answers', 'answers__question'
+        ).select_related('order', 'item', 'variation', 'addon_to')
+
+        if form_data.get('include_pending'):
+            qs = qs.filter(order__status__in=[Order.STATUS_PAID, Order.STATUS_PENDING])
+        else:
+            qs = qs.filter(order__status__in=[Order.STATUS_PAID])
+
+        outbuffer = render_pdf(self.event, qs)
+        return 'badges.pdf', 'application/pdf', outbuffer.read()