Fix Office 365 calendars to be compatible with rfc5545

homeassistant/components/remote_calendar/config_flow.py

@@ -5,15 +5,14 @@
 from typing import Any
 
 from httpx import HTTPError, InvalidURL
-from ical.calendar_stream import IcsCalendarStream
-from ical.exceptions import CalendarParseError
 import voluptuous as vol
 
 from homeassistant.config_entries import ConfigFlow, ConfigFlowResult
 from homeassistant.const import CONF_URL
 from homeassistant.helpers.httpx_client import get_async_client
 
 from .const import CONF_CALENDAR_NAME, DOMAIN
+from .ics import InvalidIcsException, parse_calendar
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -64,15 +63,9 @@ async def async_step_user(
             _LOGGER.debug("An error occurred: %s", err)
         else:
             try:
-                await self.hass.async_add_executor_job(
-                    IcsCalendarStream.calendar_from_ics, res.text
-                )
-            except CalendarParseError as err:
+                await parse_calendar(self.hass, res.text)
+            except InvalidIcsException:
                 errors["base"] = "invalid_ics_file"
-                _LOGGER.error("Error reading the calendar information: %s", err.message)
-                _LOGGER.debug(
-                    "Additional calendar error detail: %s", str(err.detailed_error)
-                )
             else:
                 return self.async_create_entry(
                     title=user_input[CONF_CALENDAR_NAME], data=user_input

homeassistant/components/remote_calendar/coordinator.py

@@ -5,8 +5,6 @@
 
 from httpx import HTTPError, InvalidURL
 from ical.calendar import Calendar
-from ical.calendar_stream import IcsCalendarStream
-from ical.exceptions import CalendarParseError
 
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import CONF_URL
@@ -15,6 +13,7 @@
 from homeassistant.helpers.update_coordinator import DataUpdateCoordinator, UpdateFailed
 
 from .const import DOMAIN
+from .ics import InvalidIcsException, parse_calendar
 
 type RemoteCalendarConfigEntry = ConfigEntry[RemoteCalendarDataUpdateCoordinator]
 
@@ -56,14 +55,9 @@ async def _async_update_data(self) -> Calendar:
                 translation_placeholders={"err": str(err)},
             ) from err
         try:
-            # calendar_from_ics will dynamically load packages
-            # the first time it is called, so we need to do it
-            # in a separate thread to avoid blocking the event loop
             self.ics = res.text
-            return await self.hass.async_add_executor_job(
-                IcsCalendarStream.calendar_from_ics, self.ics
-            )
-        except CalendarParseError as err:
+            return await parse_calendar(self.hass, res.text)
+        except InvalidIcsException as err:
             raise UpdateFailed(
                 translation_domain=DOMAIN,
                 translation_key="unable_to_parse",

homeassistant/components/remote_calendar/ics.py

@@ -0,0 +1,44 @@
+"""Module for parsing ICS content.
+
+This module exists to fix known issues where calendar providers return calendars
+that do not follow rfcc5545. This module will attempt to fix the calendar and return
+a valid calendar object.
+"""
+
+import logging
+
+from ical.calendar import Calendar
+from ical.calendar_stream import IcsCalendarStream
+from ical.compat import enable_compat_mode
+from ical.exceptions import CalendarParseError
+
+from homeassistant.core import HomeAssistant
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class InvalidIcsException(Exception):
+    """Exception to indicate that the ICS content is invalid."""
+
+
+def _compat_calendar_from_ics(ics: str) -> Calendar:
+    """Parse the ICS content and return a Calendar object.
+
+    This function is called in a separate thread to avoid blocking the event
+    loop while loading packages or parsing the ICS content for large calendars.
+
+    It uses the `enable_compat_mode` context manager to fix known issues with
+    calendar providers that return invalid calendars.
+    """
+    with enable_compat_mode(ics) as compat_ics:
+        return IcsCalendarStream.calendar_from_ics(compat_ics)
+
+
+async def parse_calendar(hass: HomeAssistant, ics: str) -> Calendar:
+    """Parse the ICS content and return a Calendar object."""
+    try:
+        return await hass.async_add_executor_job(_compat_calendar_from_ics, ics)
+    except CalendarParseError as err:
+        _LOGGER.error("Error parsing calendar information: %s", err.message)
+        _LOGGER.debug("Additional calendar error detail: %s", str(err.detailed_error))
+        raise InvalidIcsException(err.message) from err

tests/components/remote_calendar/snapshots/test_calendar.ambr

@@ -0,0 +1,19 @@
+# serializer version: 1
+# name: test_calendar_examples[office365_invalid_tzid]
+  list([
+    dict({
+      'description': None,
+      'end': dict({
+        'dateTime': '2024-04-26T15:00:00-06:00',
+      }),
+      'location': '',
+      'recurrence_id': None,
+      'rrule': None,
+      'start': dict({
+        'dateTime': '2024-04-26T14:00:00-06:00',
+      }),
+      'summary': 'Uffe',
+      'uid': '040000008200E00074C5B7101A82E00800000000687C546B5596DA01000000000000000010000000309AE93C8C3A94489F90ADBEA30C2F2B',
+    }),
+  ])
+# ---

tests/components/remote_calendar/test_calendar.py

@@ -1,11 +1,13 @@
 """Tests for calendar platform of Remote Calendar."""
 
 from datetime import datetime
+import pathlib
 import textwrap
 
 from httpx import Response
 import pytest
 import respx
+from syrupy.assertion import SnapshotAssertion
 
 from homeassistant.const import STATE_OFF, STATE_ON
 from homeassistant.core import HomeAssistant
@@ -21,6 +23,13 @@
 
 from tests.common import MockConfigEntry
 
+# Test data files with known calendars from various sources. You can add a new file
+# in the testdata directory and add it will be parsed and tested.
+TESTDATA_FILES = sorted(
+    pathlib.Path("tests/components/remote_calendar/testdata/").glob("*.ics")
+)
+TESTDATA_IDS = [f.stem for f in TESTDATA_FILES]
+
 
 @respx.mock
 async def test_empty_calendar(
@@ -392,3 +401,24 @@ async def test_all_day_iter_order(
 
     events = await get_events("2022-10-06T00:00:00Z", "2022-10-09T00:00:00Z")
     assert [event["summary"] for event in events] == event_order
+
+
+@respx.mock
+@pytest.mark.parametrize("ics_filename", TESTDATA_FILES, ids=TESTDATA_IDS)
+async def test_calendar_examples(
+    hass: HomeAssistant,
+    config_entry: MockConfigEntry,
+    get_events: GetEventsFn,
+    ics_filename: pathlib.Path,
+    snapshot: SnapshotAssertion,
+) -> None:
+    """Test parsing known calendars form test data files."""
+    respx.get(CALENDER_URL).mock(
+        return_value=Response(
+            status_code=200,
+            text=ics_filename.read_text(),
+        )
+    )
+    await setup_integration(hass, config_entry)
+    events = await get_events("1997-07-14T00:00:00", "2025-07-01T00:00:00")
+    assert events == snapshot

tests/components/remote_calendar/testdata/office365_invalid_tzid.ics

@@ -0,0 +1,58 @@
+BEGIN:VCALENDAR
+METHOD:PUBLISH
+PRODID:Microsoft Exchange Server 2010
+VERSION:2.0
+X-WR-CALNAME:Kalender
+BEGIN:VTIMEZONE
+TZID:W. Europe Standard Time
+BEGIN:STANDARD
+DTSTART:16010101T030000
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T020000
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VTIMEZONE
+TZID:UTC
+BEGIN:STANDARD
+DTSTART:16010101T000000
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0000
+END:STANDARD
+BEGIN:DAYLIGHT
+DTSTART:16010101T000000
+TZOFFSETFROM:+0000
+TZOFFSETTO:+0000
+END:DAYLIGHT
+END:VTIMEZONE
+BEGIN:VEVENT
+UID:040000008200E00074C5B7101A82E00800000000687C546B5596DA01000000000000000
+ 010000000309AE93C8C3A94489F90ADBEA30C2F2B
+SUMMARY:Uffe
+DTSTART;TZID=Customized Time Zone:20240426T140000
+DTEND;TZID=Customized Time Zone:20240426T150000
+CLASS:PUBLIC
+PRIORITY:5
+DTSTAMP:20250417T155647Z
+TRANSP:OPAQUE
+STATUS:CONFIRMED
+SEQUENCE:0
+LOCATION:
+X-MICROSOFT-CDO-APPT-SEQUENCE:0
+X-MICROSOFT-CDO-BUSYSTATUS:BUSY
+X-MICROSOFT-CDO-INTENDEDSTATUS:BUSY
+X-MICROSOFT-CDO-ALLDAYEVENT:FALSE
+X-MICROSOFT-CDO-IMPORTANCE:1
+X-MICROSOFT-CDO-INSTTYPE:0
+X-MICROSOFT-DONOTFORWARDMEETING:FALSE
+X-MICROSOFT-DISALLOW-COUNTER:FALSE
+X-MICROSOFT-REQUESTEDATTENDANCEMODE:DEFAULT
+X-MICROSOFT-ISRESPONSEREQUESTED:FALSE
+END:VEVENT
+END:VCALENDAR