agenda: add support for remote calendar file with exceptions (#19070)

Remote calendars can be specified by desk and updated hourly, or used once.

chrono/agendas/management/commands/sync_desks_timeperiod_exceptions.py

@@ -0,0 +1,32 @@
+# chrono - agendas system
+# Copyright (C) 2016-2017  Entr'ouvert
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+import six
+import sys
+
+from chrono.agendas.models import Desk, ICSError
+from django.core.management.base import BaseCommand, CommandError
+
+
+class Command(BaseCommand):
+    help = 'Synchronize time period exceptions from desks remote ics'
+
+    def handle(self, **options):
+        for desk in Desk.objects.exclude(timeperiod_exceptions_remote_url=''):
+            try:
+                desk.create_timeperiod_exceptions_from_remote_ics(desk.timeperiod_exceptions_remote_url)
+            except ICSError as e:
+                print >> sys.stderr, u'unable to create timeperiod exceptions for "%s": %s' % (desk, e)

chrono/agendas/migrations/0020_auto_20171102_1021.py

@@ -0,0 +1,32 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+import datetime
+from django.utils.timezone import utc
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('agendas', '0019_timeperiodexception'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='desk',
+            name='timeperiod_exceptions_remote_url',
+            field=models.URLField(verbose_name='URL to fetch time period exceptions from', blank=True),
+        ),
+        migrations.AddField(
+            model_name='timeperiodexception',
+            name='external_id',
+            field=models.CharField(max_length=256, verbose_name='External ID', blank=True),
+        ),
+        migrations.AddField(
+            model_name='timeperiodexception',
+            name='update_datetime',
+            field=models.DateTimeField(default=datetime.datetime(2017, 11, 2, 10, 21, 1, 826837, tzinfo=utc), auto_now=True),
+            preserve_default=False,
+        ),
+    ]

chrono/agendas/models.py

@@ -16,6 +16,7 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import datetime
+import requests
 import vobject
 
 from django.contrib.auth.models import Group
@@ -28,7 +29,7 @@ from django.utils.dates import WEEKDAYS
 from django.utils.encoding import force_text
 from django.utils.formats import date_format, get_format
 from django.utils.text import slugify
-from django.utils.timezone import localtime, now, make_aware, make_naive
+from django.utils.timezone import localtime, now, make_aware, make_naive, is_aware
 from django.utils.translation import ugettext_lazy as _
 
 from jsonfield import JSONField
@@ -358,6 +359,8 @@ class Desk(models.Model):
     agenda = models.ForeignKey(Agenda)
     label = models.CharField(_('Label'), max_length=150)
     slug = models.SlugField(_('Identifier'), max_length=150)
+    timeperiod_exceptions_remote_url = models.URLField(_('URL to fetch time period exceptions from'),
+                                    blank=True)
 
     def __unicode__(self):
         return self.label
@@ -417,7 +420,21 @@ class Desk(models.Model):
         in_two_weeks = self.get_exceptions_within_two_weeks()
         return self.timeperiodexception_set.count() == len(in_two_weeks)
 
-    def create_timeperiod_exceptions_from_ics(self, data):
+    def create_timeperiod_exceptions_from_remote_ics(self, url):
+        try:
+            response = requests.get(url)
+            response.raise_for_status()
+        except requests.HTTPError as e:
+            raise ICSError(_('Failed to retrieve remote calendar (HTTP error %s).') % e.response.status_code)
+        except requests.RequestException as e:
+            raise ICSError(_('Failed to retrieve remote calendar (%s).') % e)
+
+        return self.create_timeperiod_exceptions_from_ics(response.text, keep_synced_by_uid=True)
+
+    def remove_timeperiod_exceptions_from_remote_ics(self):
+        TimePeriodException.objects.filter(desk=self).exclude(external_id='').delete()
+
+    def create_timeperiod_exceptions_from_ics(self, data, keep_synced_by_uid=False):
         try:
             parsed = vobject.readOne(data)
         except vobject.base.ParseError:
@@ -425,12 +442,14 @@ class Desk(models.Model):
 
         total_created = 0
 
-        if not parsed.contents.get('vevent'):
+        if not parsed.contents.get('vevent') and not keep_synced_by_uid:
             raise ICSError(_('The file doesn\'t contain any events.'))
 
         with transaction.atomic():
-            for vevent in parsed.contents['vevent']:
+            update_datetime = now()
+            for vevent in parsed.contents.get('vevent', []):
                 event = {}
+
                 summary = vevent.contents['summary'][0].value
                 if not isinstance(summary, unicode):
                     summary = unicode(summary, 'utf-8')
@@ -441,7 +460,10 @@ class Desk(models.Model):
                     if not isinstance(start_dt, datetime.datetime):
                         start_dt = datetime.datetime.combine(start_dt,
                                                 datetime.datetime.min.time())
-                    event['start_datetime'] = start_dt
+                    if not is_aware(start_dt):
+                        event['start_datetime'] = make_aware(start_dt)
+                    else:
+                        event['start_datetime'] = start_dt
                 except AttributeError:
                     raise ICSError(_('Event "%s" has no start date.') % summary)
                 try:
@@ -452,21 +474,36 @@ class Desk(models.Model):
                 except AttributeError:
                     # events without end date are considered as ending the same day
                     end_dt = datetime.datetime.combine(start_dt, datetime.datetime.max.time())
-                event['end_datetime'] = end_dt
+                if not is_aware(end_dt):
-
+                    event['end_datetime'] = make_aware(end_dt)
-                obj, created = TimePeriodException.objects.get_or_create(desk=self, label=summary,
+                else:
-                                                                         **event)
+                    event['end_datetime'] = end_dt
+                if keep_synced_by_uid:
+                    external_id = vevent.contents['uid'][0].value
+                    event['label'] = summary
+                    obj, created = TimePeriodException.objects.update_or_create(desk=self, external_id=external_id,
+                                                                    defaults=event)
+                else:
+                    obj, created = TimePeriodException.objects.update_or_create(desk=self, label=summary, defaults=event)
+                # return total_created
                 if created:
                     total_created += 1
 
+            if keep_synced_by_uid:
+                # delete all outdated exceptions from remote calendar
+                TimePeriodException.objects.filter(update_datetime__lt=update_datetime,
+                                    desk=self).exclude(external_id='').delete()
+
         return total_created
 
 
 class TimePeriodException(models.Model):
     desk = models.ForeignKey(Desk)
+    external_id = models.CharField(_('External ID'), max_length=256, blank=True)
     label = models.CharField(_('Optional Label'), max_length=150, blank=True, null=True)
     start_datetime = models.DateTimeField(_('Exception start time'))
     end_datetime = models.DateTimeField(_('Exception end time'))
+    update_datetime = models.DateTimeField(auto_now=True)
 
     class Meta:
         ordering = ['start_datetime']

chrono/manager/forms.py

@@ -83,7 +83,7 @@ class NewDeskForm(forms.ModelForm):
         widgets = {
             'agenda': forms.HiddenInput(),
         }
-        exclude = ['slug']
+        exclude = ['slug', 'timeperiod_exceptions_remote_url']
 
 
 class DeskForm(forms.ModelForm):
@@ -92,7 +92,7 @@ class DeskForm(forms.ModelForm):
         widgets = {
             'agenda': forms.HiddenInput(),
         }
-        exclude = []
+        exclude = ['timeperiod_exceptions_remote_url']
 
 
 class TimePeriodExceptionForm(forms.ModelForm):
@@ -170,5 +170,7 @@ class ExceptionsImportForm(forms.ModelForm):
         model = Desk
         fields = []
 
-    ics_file = forms.FileField(label=_('ICS File'),
+    ics_file = forms.FileField(label=_('ICS File'), required=False,
                                help_text=_('ICS file containing events which will be considered as exceptions'))
+    ics_url = forms.URLField(label=_('URL'), required=False,
+                               help_text=_('URL to remote calendar which will be synchronised hourly'))

chrono/manager/templates/chrono/manager_import_exceptions.html

@@ -13,6 +13,7 @@
 {% block content %}
 
 <form method="post" enctype="multipart/form-data">
+  <p class="notice">{% trans "You can upload a file or specify an address to a remote calendar." %}</p>
   {% csrf_token %}
   {{ form.as_p }}
   <p>

chrono/manager/views.py

@@ -394,16 +394,28 @@ class DeskImportTimePeriodExceptionsView(ManagedAgendaSubobjectMixin, UpdateView
     form_class = ExceptionsImportForm
     template_name = 'chrono/manager_import_exceptions.html'
 
+    def get_initial(self):
+        return {'ics_url': self.get_object().timeperiod_exceptions_remote_url}
+
     def form_valid(self, form):
+        exceptions = None
         try:
-            exceptions = form.instance.create_timeperiod_exceptions_from_ics(form.cleaned_data['ics_file'])
+            if form.cleaned_data['ics_file']:
+                exceptions = form.instance.create_timeperiod_exceptions_from_ics(form.cleaned_data['ics_file'])
+            elif form.cleaned_data['ics_url']:
+                exceptions = form.instance.create_timeperiod_exceptions_from_remote_ics(form.cleaned_data['ics_url'])
+            else:
+                form.instance.remove_timeperiod_exceptions_from_remote_ics()
         except ICSError as e:
             form.add_error(None, unicode(e))
             return self.form_invalid(form)
-        message = ungettext('An exception has been imported.',
+        form.instance.timeperiod_exceptions_remote_url = form.cleaned_data['ics_url']
-                            '%(count)d exceptions have been imported.', exceptions)
+        form.instance.save()
-        message = message % {'count': exceptions}
+        if exceptions is not None:
-        messages.info(self.request, message)
+            message = ungettext('An exception has been imported.',
+                                '%(count)d exceptions have been imported.', exceptions)
+            message = message % {'count': exceptions}
+            messages.info(self.request, message)
         return super(DeskImportTimePeriodExceptionsView, self).form_valid(form)
 
 desk_import_time_period_exceptions = DeskImportTimePeriodExceptionsView.as_view()

debian/chrono.cron.d

@@ -0,0 +1,3 @@
+MAILTO=root
+
+0 * * * * /sbin/runuser -u chrono /usr/bin/chrono-manage -- tenant_command sync_desks_timeperiod_exceptions --all-tenants

debian/control

@@ -11,7 +11,8 @@ Architecture: all
 Depends: ${misc:Depends}, ${python:Depends},
     python-django (>= 1.8),
     python-gadjo,
-    python-intervaltree
+    python-intervaltree,
+    python-requests
 Recommends: python-django-mellon
 Description: Agendas System (Python module)
 

requirements.txt

@@ -3,3 +3,5 @@ gadjo
 djangorestframework>=3.1, <3.7
 django-jsonfield >= 0.9.3
 intervaltree
+requests
+vobject

setup.py

@@ -107,7 +107,8 @@ setup(
         'djangorestframework>=3.1, <3.7',
         'django-jsonfield >= 0.9.3',
         'intervaltree',
-        'vobject'
+        'vobject',
+        'requests'
         ],
     zip_safe=False,
     cmdclass={

tests/test_agendas.py

@@ -1,7 +1,13 @@
 import pytest
 import datetime
+import mock
+import re
+import requests
+
 
 from django.utils.timezone import now, make_aware, localtime
+from django.core.management import call_command
+from django.core.management.base import CommandError
 
 from chrono.agendas.models import (Agenda, Event, Booking, MeetingType,
                         Desk, TimePeriodException, ICSError)
@@ -22,8 +28,8 @@ END:VEVENT
 BEGIN:VEVENT
 DTSTAMP:20170824T092855Z
 UID:950c3ff889d2465dd5d648c4c2194232c0a565f4
-DTSTART:20170831T180800Z
+DTSTART:20170830T180800Z
-DTEND:20170831T213400Z
+DTEND:20170831T223400Z
 SEQUENCE:2
 SUMMARY:Event 2
 END:VEVENT
@@ -43,7 +49,7 @@ BEGIN:VEVENT
 DTSTAMP:20170824T082855Z
 DTSTART:20180101
 DTEND:20180101
-SUMMARY:New eve
+SUMMARY:New Year's Eve
 RRULE:FREQ=YEARLY
 END:VEVENT
 END:VCALENDAR"""
@@ -220,3 +226,107 @@ def test_timeexception_create_from_ics_with_no_events():
     with pytest.raises(ICSError) as e:
         exceptions_count = desk.create_timeperiod_exceptions_from_ics(ICS_SAMPLE_WITH_NO_EVENTS)
     assert str(e.value) == "The file doesn't contain any events."
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_timeperiodexception_creation_from_remote_ics(mocked_get):
+    agenda = Agenda(label=u'Test 8 agenda')
+    agenda.save()
+    desk = Desk(label='Test 8 desk', agenda=agenda)
+    desk.save()
+    mocked_response = mock.Mock()
+    mocked_response.text = ICS_SAMPLE
+    mocked_get.return_value = mocked_response
+    exceptions_count = desk.create_timeperiod_exceptions_from_remote_ics('http://example.com/sample.ics')
+    assert exceptions_count == 2
+    mocked_response.text = re.sub('SUMMARY:\w+', 'SUMMARY:New summmary', ICS_SAMPLE, re.MULTILINE)
+    mocked_get.return_value = mocked_response
+    desk.create_timeperiod_exceptions_from_remote_ics('http://example.com/sample.ics')
+    for timeperiod in TimePeriodException.objects.filter(external_id='desk-%s:' % desk.id, desk=desk):
+        assert 'New summary ' in timeperiod.label
+
+    mocked_response.text = ICS_SAMPLE_WITH_NO_EVENTS
+    mocked_get.return_value = mocked_response
+    exceptions_count = desk.create_timeperiod_exceptions_from_remote_ics('http://example.com/sample.ics')
+    assert exceptions_count == 0
+    TimePeriodException.objects.filter(external_id='desk-%s:' % desk.id).count() == 0
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_timeperiodexception_creation_from_unreachable_remote_ics(mocked_get):
+    agenda = Agenda(label=u'Test 9 agenda')
+    agenda.save()
+    desk = Desk(label='Test 9 desk', agenda=agenda)
+    desk.save()
+    mocked_response = mock.Mock()
+    mocked_response.text = ICS_SAMPLE
+    mocked_get.return_value = mocked_response
+    def mocked_requests_connection_error(*args, **kwargs):
+        raise requests.ConnectionError('unreachable')
+    mocked_get.side_effect = mocked_requests_connection_error
+    with pytest.raises(ICSError) as e:
+        exceptions_count = desk.create_timeperiod_exceptions_from_remote_ics('http://example.com/sample.ics')
+    assert str(e.value) == "Failed to retrieve remote calendar (unreachable)."
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_timeperiodexception_creation_from_forbidden_remote_ics(mocked_get):
+    agenda = Agenda(label=u'Test 10 agenda')
+    agenda.save()
+    desk = Desk(label='Test 10 desk', agenda=agenda)
+    desk.save()
+    mocked_response = mock.Mock()
+    mocked_response.status_code = 403
+    mocked_get.return_value = mocked_response
+    def mocked_requests_http_forbidden_error(*args, **kwargs):
+        raise requests.HTTPError(response=mocked_response)
+    mocked_get.side_effect = mocked_requests_http_forbidden_error
+
+    with pytest.raises(ICSError) as e:
+        exceptions_count = desk.create_timeperiod_exceptions_from_remote_ics('http://example.com/sample.ics')
+    assert str(e.value) == "Failed to retrieve remote calendar (HTTP error 403)."
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_sync_desks_timeperiod_exceptions_from_ics(mocked_get, capsys):
+    agenda = Agenda(label=u'Test 11 agenda')
+    agenda.save()
+    desk = Desk(label='Test 11 desk', agenda=agenda, timeperiod_exceptions_remote_url='http:example.com/sample.ics')
+    desk.save()
+    mocked_response = mock.Mock()
+    mocked_response.status_code = 403
+    mocked_get.return_value = mocked_response
+    def mocked_requests_http_forbidden_error(*args, **kwargs):
+        raise requests.HTTPError(response=mocked_response)
+    mocked_get.side_effect = mocked_requests_http_forbidden_error
+    call_command('sync_desks_timeperiod_exceptions')
+    out, err = capsys.readouterr()
+    assert err == 'unable to create timeperiod exceptions for "Test 11 desk": Failed to retrieve remote calendar (HTTP error 403).\n'
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_sync_desks_timeperiod_exceptions_from_changing_ics(mocked_get, caplog):
+    agenda = Agenda(label=u'Test 11 agenda')
+    agenda.save()
+    desk = Desk(label='Test 11 desk', agenda=agenda, timeperiod_exceptions_remote_url='http:example.com/sample.ics')
+    desk.save()
+    mocked_response = mock.Mock()
+    mocked_response.text = ICS_SAMPLE
+    mocked_get.return_value = mocked_response
+    call_command('sync_desks_timeperiod_exceptions')
+    assert TimePeriodException.objects.filter(desk=desk).count() == 2
+    mocked_response.text = """BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//foo.bar//EN
+BEGIN:VEVENT
+DTSTAMP:20180824T082855Z
+UID:new-and-unique-uid
+DTSTART:20180831T170800Z
+DTEND:20180831T203400Z
+SUMMARY:Wonderfull event
+END:VEVENT
+END:VCALENDAR"""
+    mocked_get.return_value = mocked_response
+    call_command('sync_desks_timeperiod_exceptions')
+    assert TimePeriodException.objects.filter(desk=desk).count() == 1
+    exception = TimePeriodException.objects.get(desk=desk)
+    assert exception.external_id == 'new-and-unique-uid'
+    mocked_response.text = ICS_SAMPLE_WITH_NO_EVENTS
+    mocked_get.return_value = mocked_response
+    call_command('sync_desks_timeperiod_exceptions')
+    assert not TimePeriodException.objects.filter(desk=desk).exists()

tests/test_manager.py

@@ -3,7 +3,9 @@
 from django.contrib.auth.models import User, Group
 from django.utils.timezone import make_aware, now, localtime
 import datetime
+import mock
 import pytest
+import requests
 from webtest import TestApp, Upload
 
 from chrono.wsgi import application
@@ -840,6 +842,10 @@ def test_agenda_import_time_period_exception_from_ics(app, admin_user):
     resp = app.get('/manage/agendas/%d/' % agenda.pk)
     assert 'Import exceptions from .ics' in resp.content
     resp = resp.click('upload')
+    assert "You can upload a file or specify an address to a remote calendar." in resp
+    resp = resp.form.submit(status=302)
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
     resp.form['ics_file'] = Upload('exceptions.ics', 'invalid content', 'text/calendar')
     resp = resp.form.submit(status=200)
     assert 'File format is invalid' in resp.content
@@ -849,7 +855,7 @@ PRODID:-//foo.bar//EN
 BEGIN:VEVENT
 DTSTART:20180101
 DTEND:20180101
-SUMMARY:New eve
+SUMMARY:New Year's Eve
 RRULE:FREQ=YEARLY
 END:VEVENT
 END:VCALENDAR"""
@@ -861,12 +867,12 @@ VERSION:2.0
 PRODID:-//foo.bar//EN
 BEGIN:VEVENT
 DTEND:20180101
-SUMMARY:New eve
+SUMMARY:New Year's Eve
 END:VEVENT
 END:VCALENDAR"""
     resp.form['ics_file'] = Upload('exceptions.ics', ics_with_no_start_date, 'text/calendar')
     resp = resp.form.submit(status=200)
-    assert 'Event "New eve" has no start date.' in resp.content
+    assert 'Event "New Year's Eve" has no start date.' in resp.content
     ics_with_no_events = """BEGIN:VCALENDAR
 VERSION:2.0
 PRODID:-//foo.bar//EN
@@ -881,11 +887,220 @@ PRODID:-//foo.bar//EN
 BEGIN:VEVENT
 DTSTART:20180101
 DTEND:20180101
-SUMMARY:New eve
+SUMMARY:New Year's Eve
 END:VEVENT
 END:VCALENDAR"""
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
     resp.form['ics_file'] = Upload('exceptions.ics', ics_with_exceptions, 'text/calendar')
     resp = resp.form.submit(status=302)
-    assert TimePeriodException.objects.count() == 1
+    assert TimePeriodException.objects.filter(desk=desk).count() == 1
     resp = resp.follow()
     assert 'An exception has been imported.' in resp.content
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_agenda_import_time_period_exception_with_remote_ics(mocked_get, app, admin_user):
+    agenda = Agenda.objects.create(label='New Example', kind='meetings')
+    desk = Desk.objects.create(agenda=agenda, label='New Desk')
+    MeetingType(agenda=agenda, label='Bar').save()
+    login(app)
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    assert 'Import exceptions from .ics' not in resp.content
+
+    TimePeriod.objects.create(weekday=1, desk=desk,
+                start_time=datetime.time(10, 0), end_time=datetime.time(12, 0))
+
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+
+    assert 'ics_file' in resp.form.fields
+    assert 'ics_url' in resp.form.fields
+    resp.form['ics_url'] = 'http://example.com/foo.ics'
+    mocked_response = mock.Mock()
+    mocked_response.text =  """BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//foo.bar//EN
+BEGIN:VEVENT
+UID:random-event-id
+DTSTART:20180101
+DTEND:20180101
+SUMMARY:New Year's Eve
+END:VEVENT
+END:VCALENDAR"""
+    mocked_get.return_value = mocked_response
+    resp = resp.form.submit(status=302)
+    assert TimePeriodException.objects.filter(desk=desk).count() == 1
+    exception = TimePeriodException.objects.get(desk=desk)
+    assert exception.external_id == 'random-event-id'
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+    resp.form['ics_url'] = ''
+    resp = resp.form.submit(status=302)
+    assert not TimePeriodException.objects.filter(desk=desk,
+                    external_id='desk-%s:random-event-id' % desk.id).exists()
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_agenda_import_time_period_exception_with_remote_ics_no_events(mocked_get, app, admin_user):
+    agenda = Agenda.objects.create(label='New Example', kind='meetings')
+    desk = Desk.objects.create(agenda=agenda, label='New Desk')
+    MeetingType(agenda=agenda, label='Bar').save()
+    login(app)
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    assert 'Import exceptions from .ics' not in resp.content
+
+    TimePeriod.objects.create(weekday=1, desk=desk,
+                start_time=datetime.time(10, 0), end_time=datetime.time(12, 0))
+
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+    resp.form['ics_url'] = 'http://example.com/foo.ics'
+    mocked_response = mock.Mock()
+    mocked_response.text =  """BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//foo.bar//EN
+BEGIN:VEVENT
+UID:random-event-id
+DTSTART:20180101
+DTEND:20180101
+SUMMARY:New Year's Eve
+END:VEVENT
+END:VCALENDAR"""
+    mocked_get.return_value = mocked_response
+    resp = resp.form.submit(status=302)
+    assert TimePeriodException.objects.filter(desk=desk).count() == 1
+    exception = TimePeriodException.objects.get(desk=desk)
+    assert exception.external_id == 'random-event-id'
+    mocked_response.text = """BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//foo.bar//EN
+END:VCALENDAR"""
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+    resp = resp.form.submit(status=302)
+    assert not TimePeriodException.objects.filter(desk=desk,
+                    external_id='random-event-id').exists()
+
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_agenda_update_time_period_exception_from_remote_ics(mocked_get, app, admin_user):
+    agenda = Agenda.objects.create(label='New Example', kind='meetings')
+    desk = Desk.objects.create(agenda=agenda, label='New Desk')
+    MeetingType(agenda=agenda, label='Bar').save()
+    login(app)
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    assert 'Import exceptions from .ics' not in resp.content
+
+    TimePeriod.objects.create(weekday=1, desk=desk,
+                start_time=datetime.time(10, 0), end_time=datetime.time(12, 0))
+
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+    resp.form['ics_url'] = 'http://example.com/foo.ics'
+    mocked_response = mock.Mock()
+    mocked_response.text =  """BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//foo.bar//EN
+BEGIN:VEVENT
+UID:first-eventrandom-event-id
+DTSTART:20180101
+DTEND:20180101
+SUMMARY:First test event
+END:VEVENT
+BEGIN:VEVENT
+UID:second-eventrandom-event-id
+DTSTART:20190101
+DTEND:20190101
+SUMMARY:Second test event
+END:VEVENT
+END:VCALENDAR"""
+    mocked_get.return_value = mocked_response
+    resp = resp.form.submit(status=302)
+    assert TimePeriodException.objects.filter(desk=desk).count() == 2
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+    resp.form['ics_url'] = 'http://example.com/foo.ics'
+    mocked_response.text = """BEGIN:VCALENDAR
+VERSION:2.0
+PRODID:-//foo.bar//EN
+BEGIN:VEVENT
+UID:secord-eventrandom-event-id
+DTSTART:20190101
+DTEND:20190101
+SUMMARY:Second test event
+END:VEVENT
+END:VCALENDAR"""
+    mocked_get.return_value = mocked_response
+    resp = resp.form.submit(status=302)
+    assert TimePeriodException.objects.filter(desk=desk).count() == 1
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_agenda_import_time_period_exception_from_remote_ics_with_connection_error(mocked_get, app, admin_user):
+    agenda = Agenda.objects.create(label='New Example', kind='meetings')
+    desk = Desk.objects.create(agenda=agenda, label='New Desk')
+    MeetingType(agenda=agenda, label='Bar').save()
+    login(app)
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    assert 'Import exceptions from .ics' not in resp.content
+
+    TimePeriod.objects.create(weekday=1, desk=desk,
+                start_time=datetime.time(10, 0), end_time=datetime.time(12, 0))
+
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+
+    assert 'ics_file' in resp.form.fields
+    assert 'ics_url' in resp.form.fields
+    resp.form['ics_url'] = 'http://example.com/foo.ics'
+    mocked_response = mock.Mock()
+    mocked_get.return_value = mocked_response
+    def mocked_requests_connection_error(*args, **kwargs):
+        raise requests.exceptions.ConnectionError('unreachable')
+    mocked_get.side_effect = mocked_requests_connection_error
+    resp = resp.form.submit(status=200)
+    assert 'Failed to retrieve remote calendar (unreachable).' in resp.content
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_agenda_import_time_period_exception_from_forbidden_remote_ics(mocked_get, app, admin_user):
+    agenda = Agenda.objects.create(label='New Example', kind='meetings')
+    desk = Desk.objects.create(agenda=agenda, label='New Desk')
+    MeetingType(agenda=agenda, label='Bar').save()
+    login(app)
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    assert 'Import exceptions from .ics' not in resp.content
+
+    TimePeriod.objects.create(weekday=1, desk=desk,
+                start_time=datetime.time(10, 0), end_time=datetime.time(12, 0))
+
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+    resp.form['ics_url'] = 'http://example.com/foo.ics'
+    mocked_response = mock.Mock()
+    mocked_response.status_code = 403
+    mocked_get.return_value = mocked_response
+    def mocked_requests_http_forbidden_error(*args, **kwargs):
+        raise requests.exceptions.HTTPError(response=mocked_response)
+    mocked_get.side_effect = mocked_requests_http_forbidden_error
+    resp = resp.form.submit(status=200)
+    assert 'Failed to retrieve remote calendar (HTTP error 403).' in resp.content
+
+@mock.patch('chrono.agendas.models.requests.get')
+def test_agenda_import_time_period_exception_from_remote_ics_with_ssl_error(mocked_get, app, admin_user):
+    agenda = Agenda.objects.create(label='New Example', kind='meetings')
+    desk = Desk.objects.create(agenda=agenda, label='New Desk')
+    MeetingType(agenda=agenda, label='Bar').save()
+    login(app)
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    assert 'Import exceptions from .ics' not in resp.content
+    TimePeriod.objects.create(weekday=1, desk=desk,
+                start_time=datetime.time(10, 0), end_time=datetime.time(12, 0))
+
+    resp = app.get('/manage/agendas/%d/' % agenda.pk)
+    resp = resp.click('upload')
+    resp.form['ics_url'] = 'https://example.com/foo.ics'
+    mocked_response = mock.Mock()
+    mocked_get.return_value = mocked_response
+    def mocked_requests_http_ssl_error(*args, **kwargs):
+        raise requests.exceptions.SSLError('SSL error')
+    mocked_get.side_effect = mocked_requests_http_ssl_error
+    resp = resp.form.submit(status=200)
+    assert 'Failed to retrieve remote calendar (SSL error).' in resp.content