Move towards a more object-oriented API

fabcal/calendar_client.py

@@ -10,7 +10,7 @@ import recurring_ical_events
 import yaml
 
 from asyncache import cached
-from cachetools import TTLCache
+from cachetools import TTLCache, LRUCache
 from icalendar import Calendar
 
 from fabcal.models import CalendarEvent
@@ -22,8 +22,20 @@ class ConfiguredCalendar(NamedTuple):
     default_color: str = None
 
 
-# this is not ideal, since it will read the file (at most) every 2 minutes, but there is no good way to cache the
-# settings, e.g., by storing it in the FastAPI object
+class CalendarClient:
+    def __init__(self, url: str):
+        self.url = url
+
+    async def get(self, session):
+        async with session.get(self.url) as response:
+            response.raise_for_status()
+            assert response.content_type.lower() == "text/calendar"
+
+            return await response.text()
+
+
+# this will be cached permanently, i.e., the server process needs to be restarted to apply config changes
+@cached(LRUCache(100))
 def read_calendars_from_config_file():
     with open("config.yml") as f:
         data = yaml.safe_load(f)
@@ -32,55 +44,61 @@ def read_calendars_from_config_file():
             yield ConfiguredCalendar(**calendar)
 
 
+
+class CombinedCalendarClient:
+    def __init__(self, configured_calendars: List[ConfiguredCalendar]):
+        # make sure it's a list since read_calendars_from_config_file() returns an iterator
+        self.configured_calendars = list(configured_calendars)
+
+    async def fetch_calendars(self) -> Dict[ConfiguredCalendar, str]:
+        async with aiohttp.ClientSession() as session:
+            calendar_clients = [CalendarClient(calendar.url) for calendar in self.configured_calendars]
+            responses = await asyncio.gather(*[calendar.get(session) for calendar in calendar_clients])
+
+        return dict(zip(self.configured_calendars, responses))
+
+    @staticmethod
+    def combine_calendars(data: Dict[ConfiguredCalendar, str]) -> Calendar:
+        combined_calendar = Calendar()
+
+        combined_calendar.add("prodid", "-//FabCal//NONSGML//EN")
+        combined_calendar.add("version", "2.0")
+        combined_calendar.add("x-wr-calname", "FabLab Altmühlfranken e.V.")
+        # TODO: normalize timezones of calendar events
+
+        for configured_calendar, ical_str in data.items():
+            cal = Calendar.from_ical(ical_str)
+
+            # check for a calendar color (e.g., Nextcloud has such a feature)
+            # events that don't have a color assigned will be assigned this color unless a color was configured
+            default_color = configured_calendar.default_color
+
+            if not default_color:
+                try:
+                    # note: for some reason, getattr doesn't work
+                    default_color = cal["x-apple-calendar-color"]
+                except KeyError:
+                    default_color = None
+
+            # we don't copy anything but events from the
+            for event in cal.walk("VEVENT"):
+                # if no color has been configured in the event, we
+
+                if "color" not in event:
+                    event["color"] = default_color
+
+                combined_calendar.add_component(event)
+
+        return combined_calendar
+
+    async def fetch_and_combine_calendars(self) -> Calendar:
+        return self.combine_calendars(await self.fetch_calendars())
+
+
 @cached(TTLCache(maxsize=100, ttl=int(os.environ.get("FABCAL_CACHE_EXPIRE", 120))))
-async def get_data() -> Dict[ConfiguredCalendar, str]:
-    calendars = list(read_calendars_from_config_file())
-
-    async with aiohttp.ClientSession() as session:
-
-        async def get(url: str) -> str:
-            async with session.get(url) as response:
-                response.raise_for_status()
-                assert response.content_type.lower() == "text/calendar"
-
-                return await response.text()
-
-        responses = await asyncio.gather(*[get(calendar.url) for calendar in calendars])
-
-    return dict(zip(calendars, responses))
-
-
-def combined_calendar(data: Dict[ConfiguredCalendar, str]) -> Calendar:
-    combined_calendar = Calendar()
-
-    combined_calendar.add("prodid", "-//FabCal//NONSGML//EN")
-    combined_calendar.add("version", "2.0")
-    combined_calendar.add("x-wr-calname", "FabLab Altmühlfranken e.V.")
-    # TODO: normalize timezones of calendar events
-
-    for configured_calendar, ical_str in data.items():
-        cal = Calendar.from_ical(ical_str)
-
-        # check for a calendar color (e.g., Nextcloud has such a feature)
-        # events that don't have a color assigned will be assigned this color unless a color was configured
-        default_color = configured_calendar.default_color
-
-        if not default_color:
-            try:
-                # note: for some reason, getattr doesn't work
-                default_color = cal["x-apple-calendar-color"]
-            except KeyError:
-                default_color = None
-
-        # we don't copy anything but events from the
-        for event in cal.walk("VEVENT"):
-            # if no color has been configured in the event, we
-
-            if "color" not in event:
-                event["color"] = default_color
-
-            combined_calendar.add_component(event)
-
+async def get_data() -> Calendar:
+    client = CombinedCalendarClient(read_calendars_from_config_file())
+    combined_calendar = await client.fetch_and_combine_calendars()
     return combined_calendar
 
 
@@ -88,7 +106,7 @@ def get_tzinfo():
     return timezone(timedelta(hours=1))
 
 
-def get_events_from_calendar_string(cal: Calendar) -> List[CalendarEvent]:
+def get_events_from_calendar(cal: Calendar) -> List[CalendarEvent]:
     """
     Generate list of events from calendar vevents.
     Expands recurring events for +- one year.
@@ -147,9 +165,7 @@ def get_events_from_calendar_string(cal: Calendar) -> List[CalendarEvent]:
 
 
 async def get_future_events():
-    cal = combined_calendar(await get_data())
-
-    events = get_events_from_calendar_string(cal)
+    events = get_events_from_calendar(await get_data())
 
     today = datetime.today().date()
 

fabcal/routers/api_v1.py

@@ -1,7 +1,7 @@
 from fastapi import APIRouter
 from starlette.responses import Response
 
-from fabcal.calendar_client import combined_calendar, get_data
+from fabcal.calendar_client import get_data
 
 
 router = APIRouter()
@@ -10,7 +10,7 @@ router = APIRouter()
 @router.get("/events.ics")
 async def events_ics():
     return Response(
-        combined_calendar(await get_data()).to_ical(True),
+        (await get_data()).to_ical(True),
         headers={
             "content-type": "text/calendar",
         },