create and show access qr code

src/c3nav/control/templates/control/access.html

@@ -0,0 +1,9 @@
+{% extends 'control/base.html' %}
+{% load i18n %}
+
+{% block heading %}{% trans 'Access Permissions' %}{% endblock %}
+
+{% block subcontent %}
+    {% trans 'Generate QR Code' as button_label %}
+    {% include 'control/fragment_access_permissions_form.html' with button_label=button_label %}
+{% endblock %}

src/c3nav/control/templates/control/access_qr.html

@@ -0,0 +1,25 @@
+{% extends 'control/base.html' %}
+{% load i18n %}
+
+{% block heading %}{% trans 'Access Permission QR Code' %}{% endblock %}
+
+{% block addattributes %} style="text-align: center;"{% endblock %}
+{% block menu %}{% endblock %}
+
+{% block subcontent %}
+    <p>
+        {% trans 'Scan this QR code to get access permissions:' %}
+    </p>
+    <p>
+        <img src="/qr/access/{{ token }}">
+    </p>
+    <p>
+        {{ absolute_url }}
+    </p>
+    <p>
+        <a href="{% url 'control.access' %}">« {% trans 'back' %}</a>
+    </p>
+    <script type="text/javascript">
+        window.setTimeout(function() { window.location.reload(); }, 3000);
+    </script>
+{% endblock %}

src/c3nav/control/templates/control/base.html

@@ -6,15 +6,18 @@
 {% block header_title_url %}{% url 'control.index' %}{% endblock %}
 
 {% block content %}
-<main class="control">
+<main class="control"{% block addattributes %}{% endblock %}>
     {% include 'site/fragment_messages.html' %}
     <h2>{% block heading %}{% endblock %}</h2>
+    {% block menu %}
     <nav>
         <p>
             <a href="{% url 'control.index' %}">{% trans 'Overview' %}</a> &middot;
-            <a href="{% url 'control.users' %}">{% trans 'Users' %}</a>
+            <a href="{% url 'control.users' %}">{% trans 'Users' %}</a> &middot;
+            <a href="{% url 'control.access' %}">{% trans 'Access' %}</a>
         </p>
     </nav>
+    {% endblock %}
     {% block subcontent %}
     {% endblock %}
 </main>

src/c3nav/control/urls.py

@@ -1,9 +1,11 @@
 from django.conf.urls import url
 
-from c3nav.control.views import main_index, user_detail, user_list
+from c3nav.control.views import grant_access, grant_access_qr, main_index, user_detail, user_list
 
 urlpatterns = [
     url(r'^users/$', user_list, name='control.users'),
     url(r'^users/(?P<user>\d+)/$', user_detail, name='control.users.detail'),
+    url(r'^access/$', grant_access, name='control.access'),
+    url(r'^access/qr/(?P<token>[^/]+)', grant_access_qr, name='control.access.qr'),
     url(r'^$', main_index, name='control.index'),
 ]

src/c3nav/control/views.py

@@ -5,13 +5,15 @@ from django.contrib.auth.decorators import login_required
 from django.contrib.auth.models import User
 from django.core.exceptions import PermissionDenied
 from django.core.paginator import Paginator
+from django.db import transaction
 from django.db.models import Prefetch
 from django.shortcuts import get_object_or_404, redirect, render
+from django.urls import reverse
 from django.utils.translation import ugettext_lazy as _
 
 from c3nav.control.forms import AccessPermissionForm, UserPermissionsForm
 from c3nav.control.models import UserPermissions
-from c3nav.mapdata.models.access import AccessPermission
+from c3nav.mapdata.models.access import AccessPermission, AccessPermissionToken
 
 
 def control_panel_view(func):
@@ -112,3 +114,53 @@ def user_detail(request, user):
     })
 
     return render(request, 'control/user.html', ctx)
+
+
+@login_required
+@control_panel_view
+def grant_access(request):
+    if request.method == 'POST' and request.POST.get('submit_access_permissions'):
+        form = AccessPermissionForm(request=request, data=request.POST)
+        if form.is_valid():
+            token = form.get_token()
+            token.save()
+            return redirect(reverse('control.access.qr', kwargs={'token': token.id}))
+    else:
+        form = AccessPermissionForm(request=request)
+
+    ctx = {
+        'access_permission_form': form
+    }
+
+    return render(request, 'control/access.html', ctx)
+
+
+@login_required
+@control_panel_view
+def grant_access_qr(request, token):
+    with transaction.atomic():
+        token = AccessPermissionToken.objects.select_for_update().get(id=token, author=request.user)
+        if token.redeemed:
+            messages.success(_('Access successfully granted!'))
+            token = None
+        elif not token.unlimited:
+            try:
+                latest = AccessPermissionToken.objects.filter(author=request.user).latest('valid_until')
+            except AccessPermissionToken.DoesNotExist:
+                token = None
+            else:
+                if latest.id != token.id:
+                    token = None
+            if token is None:
+                messages.error(_('You can only display your most recently created token.'))
+
+        if token is None:
+            redirect('control.access')
+
+        token.bump()
+        token.save()
+
+    return render(request, 'control/access_qr.html', {
+        'token': token.id,
+        'absolute_url': request.build_absolute_uri('/access/qr/%s' % token.id)
+    })

src/c3nav/mapdata/models/access.py

@@ -78,6 +78,9 @@ class AccessPermissionToken(models.Model):
         if self.pk:
             self.save()
 
+    def bump(self):
+        self.valid_until = default_valid_until()
+
 
 class AccessPermission(models.Model):
     user = models.ForeignKey(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)