add qr code view to site

src/c3nav/site/urls.py

@@ -1,9 +1,10 @@
 from django.conf.urls import url
 
-from c3nav.site.views import main, map_image
+from c3nav.site.views import main, map_image, qr_code
 
 urlpatterns = [
     url(r'^map/(?P<level>[a-z0-9-_:]+)/(?P<area>[a-z0-9-_:]+).png$', map_image, name='site.level_image'),
+    url(r'^qr/(?P<location>[a-z0-9-_:]+).png$', qr_code, name='site.qr'),
     url(r'^l/(?P<location>[a-z0-9-_:]+)/$', main, name='site.location'),
     url(r'^o/(?P<origin>[a-z0-9-_:]+)/$', main, name='site.origin'),
     url(r'^d/(?P<destination>[a-z0-9-_:]+)/$', main, name='site.destination'),

src/c3nav/site/views.py

@@ -1,6 +1,7 @@
 from calendar import timegm
 from datetime import timedelta
 
+import qrcode
 from django.core.files import File
 from django.http import Http404, HttpResponse, HttpResponseNotModified
 from django.shortcuts import get_object_or_404, redirect, render
@@ -48,6 +49,23 @@ def get_location_or_404(request, location):
     return location
 
 
+def qr_code(request, location):
+    location = get_location_or_404(request, location)
+
+    qr = qrcode.QRCode(
+        version=1,
+        error_correction=qrcode.constants.ERROR_CORRECT_L,
+        box_size=10,
+        border=4,
+    )
+    qr.add_data(request.build_absolute_uri(reverse('site.location', kwargs={'location': location.location_id})))
+    qr.make(fit=True)
+
+    response = HttpResponse(content_type='image/png')
+    qr.make_image().save(response, 'PNG')
+    return response
+
+
 def main(request, location=None, origin=None, destination=None):
     location = get_location_or_404(request, location)
     origin = get_location_or_404(request, origin)