started calendar export

course_selection/models.py

@@ -2,6 +2,7 @@
 from django.db.models.signals import post_save
 from django.contrib.auth.models import AbstractBaseUser, User
 import settings.common as settings
+import uuid
 
 
 class Semester(models.Model):
@@ -156,6 +157,7 @@ class Schedule(models.Model):
     available_colors = models.TextField(null=True)
     enrollments = models.TextField(null=True)
     title = models.CharField(max_length=100, default="schedule")
+    ical_uuid = models.UUIDField(default=uuid.uuid4, unique=True) # uuid.uuid4 generates a random UUID (Universally Unique ID)
 
 # class Enrollment(models.Model):
 #    # each course enrollment has

course_selection/urls.py

@@ -43,4 +43,6 @@
 
     url(r'^api/worksheet/(?P<schedule_id>\d+)$',
         views.get_worksheet_pdf, name='get-worksheet-pdf'),
+
+    url(r'^ical/(?P<cal_id>).*\.ics$', views.ical_feed, name='ical-feed'),
 )

course_selection/views.py

@@ -5,6 +5,7 @@
 from django.db.models import Q
 from django.core.cache import caches
 from django.views.decorators.cache import cache_page
+from django.urls import reverse
 # send regardless of whether Django thinks we should
 
 from view_cache_utils import cache_page_with_prefix
@@ -329,3 +330,116 @@ def fill_out_course(context, idx, enrollment):
     context[checkbox_name] = checkbox_val
     context[course_name] = course.primary_listing()
     return context
+
+
+
+
+## CALENDAR EXPORT
+from icalendar import Calendar, Event, vCalAddress, vText, vDatetime, vRecur
+from datetime import datetime, timedelta
+from time import time
+from dateutil import parser as dt_parser
+import pytz
+import re
+
+@require_GET
+@never_cache
+def ical_feed(request, cal_id):
+    """
+    iCal feed
+    Kept up-to-date
+    Parameter: cal_id, which is a guid that is 1:1 with schedules in our database
+    """
+    cal = Calendar()
+    cal.add('prodid', '-//Recal Course Planner//recal.io//')
+    cal.add('version', '2.0')
+
+    sched = Schedule.objects.get(Q(ical_uuid=cal_id))
+    semester = sched.semester
+
+    cal.add('X-WR-CALNAME', 'ReCal %s (%s)' % (unicode(semester), sched.user.netid))
+    cal.add('X-WR-CALDESC', sched.title) #'ReCal Schedule'
+    cal.add('X-PUBLISHED-TTL', 'PT15M') # https://msdn.microsoft.com/en-us/library/ee178699(v=exchg.80).aspx. 15 minute updates.
+
+    tz = pytz.timezone("US/Eastern") # pytz.utc
+    # recurrence
+    ical_days = {
+        0: 'MO',
+        1: 'TU',
+        2: 'WE',
+        3: 'TH',
+        4: 'FR'
+    }
+    builtin_days = {
+        'M': 0,
+        'T': 1,
+        'W': 2,
+        'Th': 3,
+        'F': 4
+    }
+
+    #data = [hydrate_course_dict(Course.objects.get(Q(id=course['course_id']))) for course in json.loads(sched.enrollments)]
+
+    day_of_week_semester_start = semester.start_date.weekday() # 0-6, monday is 0, sunday is 6. we will have values of 0 (Monday) or 2 (Wednesday)
+
+    for course_obj in json.loads(sched.enrollments):
+        #course = Course.objects.get(Q(id=course_obj['course_id'])) # course_obj is json object; course is model
+        for section_id in course_obj['sections']:
+            section = Section.objects.get(Q(id=section_id))
+            for meeting in section.meetings.all():
+                event = Event()
+                event.add('summary', unicode(section)) # name of the event
+                event.add('location', vText(meeting.location + ', Princeton, NJ'))
+
+                ## compute first meeting date.
+                # days when the class meets. convert them to day difference relative to first date of the semester
+                daysofweek = [builtin_days[i] for i in meeting.days.split() ] # split by space. format: 0-4. monday is 0, friday is 4. matches python weekday() format.
+                dayofweek_relative_to_semester_start = []
+                for dow in daysofweek:
+                    diff = dow - day_of_week_semester_start
+                    if diff < 0:
+                        diff += 7 # add a week
+                    dayofweek_relative_to_semester_start.append(diff)
+                assert all([d > 0 for d in dayofweek_relative_to_semester_start]) # all must be positive
+                first_meeting_dayofweek = min(dayofweek_relative_to_semester_start) # a T,Th class will have first meeting on T if semester starts on M, or on Th if semester starts on Wed.
+
+                ## get meeting time
+                # meeting.start_time, meeting.end_time examples: "03:20 PM", "10:00 AM"
+                start_time = dt_parser.parse(meeting.start_time)
+                end_time = dt_parser.parse(meeting.end_time)
+
+                ## add event time.
+                event.add('dtstart', tz.localize(datetime(semester.start_date.year, semester.start_date.month , semester.start_date.day , start_time.hour, start_time.minute , 0) + timedelta(days=first_meeting_dayofweek))) #year,month,day, hour,min,second in ET
+                event.add('dtend', tz.localize(datetime(semester.start_date.year, semester.start_date.month , semester.start_date.day , end_time.hour, end_time.minute , 0) + timedelta(days=first_meeting_dayofweek)))
+                event.add('dtstamp', tz.localize(datetime(semester.start_date.year, semester.start_date.month, semester.start_date.day, 0,0,0))) # "property specifies the DATE-TIME that iCalendar object was created". per 3.8.7.2 of RFC 5545, must be in UTC
+
+                ## recurring event config
+                # producing e.g.: RRULE:FREQ=WEEKLY;UNTIL=[LAST DAY OF SEMESTER + 1];WKST=SU;BYDAY=TU,TH
+                selected_days = [ical_days[i] for i in sorted(daysofweek) ] # formatted for ical
+                end_date = tz.localize(datetime(semester.end_date.year, semester.end_date.month, semester.end_date.day, 0, 0, 0) + timedelta(days=1)) #[LAST DAY OF SEMESTER + 1]
+                event.add('rrule', vRecur({'FREQ': 'WEEKLY', 'UNTIL': end_date, 'WKST': 'SU', 'BYDAY': selected_days}))
+                cal.add_component(event)
+
+    ical = cal.to_ical()
+
+    # filter out blank lines
+    #filtered = filter(lambda x: not re.match(r'^\s*$', x), ical)
+    #print filtered
+    return HttpResponse(ical, 'text/calendar', status=200)
+
+import uuid
+def get_ical_url_for_schedule(request, schedule_id, make_new=False):
+    """
+    Returns ical feed url for a particular schedule
+    Parameter: schedule_id
+    We look up the UUID that is 1:1 to this schedule. Each schedule has a UUID always (it is auto-created.)
+    If make_new, then we create a new UUID for the schedule.
+    Then we return the url with it
+    """
+    schedule = Schedule.objects.get(Q(id=schedule_id))
+    if make_new:
+        schedule.ical_uuid = uuid.uuid4()
+        schedule.save()
+    return request.build_absolute_uri(reverse('ical-feed', args=(schedule.ical_uuid,)))
+
+