Add possibility to add additional dates to recurring events (#45)

* Ignore new line at end of file (it breaks the custom ics parser)
* Add possibility to add additional dates to recurring events
* Incorporate feedback from @stefanv. Thank you!
* Remove YAML whitespace that is actually not needed

example/test_calendar.yaml

@@ -33,7 +33,7 @@ events:
         weeks: 1
       until: 2022-12-31 # required
 
-  - summary: Recurring event with exception
+  - summary: Recurring event with exception and additional date
     begin: 2022-07-01 10:00:00
     duration: { minutes: 60 }
     repeat:
@@ -44,6 +44,8 @@ events:
       except_on:
         - 2022-07-13
         - 2022-07-14 06:00:00
+      also_on:
+        - 2022-12-24 06:00:00
 
   # All-day event
   - summary: Earth Day

tests/test_events.py

@@ -69,7 +69,7 @@ def test_exception():
     event = event_from_yaml(
         parse_yaml(
             """
-            summary: Recurring event with exception
+            summary: Recurring event with exception and additional date
             timezone: America/Los_Angeles
             begin: 2022-07-01 10:00:00
             duration: {minutes: 60}
@@ -80,6 +80,8 @@ def test_exception():
               except_on:
                 - 2022-07-13
                 - 2022-07-14 06:00:00
+              also_on:
+                - 2022-12-24 06:00:00
             """
         )
     )
@@ -90,6 +92,7 @@ def test_exception():
         "EXDATE;TZID=/ics.py/2020.1/America/Los_Angeles:20220713,20220714T060000"
         in event_str
     )
+    assert "RDATE;TZID=/ics.py/2020.1/America/Los_Angeles:20221224T060000" in event_str
 
 
 def test_event_with_time_range():

yaml2ics.py

@@ -25,11 +25,26 @@
 }
 
 
-def strfexception(exdate):
-    if isinstance(exdate, datetime.datetime):
-        return datetime.datetime.strftime(exdate, "%Y%m%dT%H%M%S")
-    elif isinstance(exdate, datetime.date):
-        return datetime.datetime.strftime(exdate, "%Y%m%d")
+def datetime2utc(date):
+    if isinstance(date, datetime.datetime):
+        return datetime.datetime.strftime(date, "%Y%m%dT%H%M%S")
+    elif isinstance(date, datetime.date):
+        return datetime.datetime.strftime(date, "%Y%m%d")
+
+
+# See RFC2445, 4.8.5 REcurrence Component Properties
+# This function can be used to add a list of e.g. exception dates (EXDATE) or recurrence dates (RDATE)
+# to a reoccurring event
+def add_recurrence_property(
+    event: ics.Event, property_name, dates: map, tz: datetime.tzinfo = None
+):
+    event.extra.append(
+        ics.ContentLine(
+            name=property_name,
+            params={"TZID": [str(ics.Timezone.from_tzinfo(tz))]} if tz else None,
+            value=",".join(dates),
+        )
+    )
 
 
 def event_from_yaml(event_yaml: dict, tz: datetime.tzinfo = None) -> ics.Event:
@@ -100,25 +115,12 @@ def event_from_yaml(event_yaml: dict, tz: datetime.tzinfo = None) -> ics.Event:
         )
 
         if "except_on" in repeat:
-            exdates = map(
-                lambda exdate: strfexception(exdate),
-                repeat["except_on"],
-            )
-            if tz:
-                event.extra.append(
-                    ics.ContentLine(
-                        name="EXDATE",
-                        params={"TZID": [str(ics.Timezone.from_tzinfo(tz))]},
-                        value=",".join(exdates),
-                    )
-                )
-            else:
-                event.extra.append(
-                    ics.ContentLine(
-                        name="EXDATE",
-                        value=",".join(exdates),
-                    )
-                )
+            exdates = [datetime2utc(rdate) for rdate in repeat["except_on"]]
+            add_recurrence_property(event, "EXDATE", exdates, tz)
+
+        if "also_on" in repeat:
+            rdates = [datetime2utc(rdate) for rdate in repeat["also_on"]]
+            add_recurrence_property(event, "RDATE", rdates, tz)
 
     event.dtstamp = datetime.datetime.utcnow().replace(tzinfo=dateutil.tz.UTC)
     if tz and event.floating and not event.all_day: