From 7e960881ae6cbcd709538dcd73e4fd89e33507d3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Markus=20Zapke-Gru=CC=88ndemann?= <info@keimlink.de>
Date: Wed, 4 Jan 2012 23:58:44 +0100
Subject: Added model, admin, tests and tasks for calendarium.

---
 sublab_project/calendarium/tasks.py | 82 +++++++++++++++++++++++++++++++++++++
 1 file changed, 82 insertions(+)
 create mode 100644 sublab_project/calendarium/tasks.py

(limited to 'sublab_project/calendarium/tasks.py')

diff --git a/sublab_project/calendarium/tasks.py b/sublab_project/calendarium/tasks.py
new file mode 100644
index 0000000..9174105
--- /dev/null
+++ b/sublab_project/calendarium/tasks.py
@@ -0,0 +1,82 @@
+"""Celery tasks.
+"""
+from datetime import datetime, timedelta
+from dateutil.relativedelta import relativedelta
+import urllib2
+
+from celery.task import PeriodicTask
+from django.conf import settings
+from dateutil.rrule import rrulestr
+import icalendar
+
+from models import Event
+
+
+class CalendariumImport(PeriodicTask):
+    """Periodic task for importing calendar events.
+    """
+    run_every = timedelta(hours=1)
+    ignore_result = True
+
+    def flush(self):
+        """Flushes all previously imported events.
+        """
+        Event.objects.filter(source=Event.SOURCE_IMPORT).delete()
+        self.logger.info('Flushed all previously imported events.')
+
+    def fetch_calendar(self):
+        """Fetches the calendar events and returns a icalendar.Calendar instance.
+        """
+        response = urllib2.urlopen(settings.CALENDARIUM_IMPORT_URL)
+        self.logger.info('Fetched calendar from %s' % settings.CALENDARIUM_IMPORT_URL)
+        return icalendar.Calendar.from_string(response.read())
+
+    def get_events(self, calendar, after, before):
+        """Yields all events in calendar as dictionary.
+
+        Only events after (including) after will be shown. Recurring events
+        til before (inclusively) will be shown.
+        """
+        for event in calendar.walk('vevent'):
+            event_fields = [
+                    # dest, src, default
+                    ('name', 'summary', 'unknown Event'),
+                    ('description', 'description', ''),
+            ]
+            event_info = {}
+            for fieldinfo in event_fields:
+                try:
+                    event_info[fieldinfo[0]] = str(event[fieldinfo[1]])
+                except KeyError:
+                    event_info[fieldinfo[0]] = fieldinfo[2]
+            start = icalendar.vDatetime.from_ical(event['dtstart'].ical())
+            end = icalendar.vDatetime.from_ical(event['dtend'].ical())
+            if 'rrule' in event:
+                rrule = rrulestr(event['rrule'].ical(), dtstart=start)
+                duration = end - start
+                for occurence in rrule.between(after, before, True):
+                    event_info['start'] = occurence
+                    event_info['end'] = occurence + duration
+                    yield event_info
+            else:
+                if start >= after:
+                    event_info['start'] = start
+                    event_info['end'] = end
+                    yield event_info
+
+    def run(self, **kwargs):
+        """Imports all events.
+        """
+        self.logger = self.get_logger(**kwargs)
+        now = datetime.now()
+        after = now - relativedelta(days=1)
+        before = now + relativedelta(months=+2)
+        self.logger.info('Importing events from %s to %s' % (after, before))
+        try:
+            calendar = self.fetch_calendar()
+            self.flush()
+            for event_info in self.get_events(calendar, after, before):
+                event = Event.objects.create(**event_info)
+                self.logger.info('Added event "%s".' % event)
+        except urllib2.URLError, error:
+            self.logger.error(error)
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