Added support for parsing VEVENT from iCal format #465

iainbeeston · 2019-01-12T16:09:01Z

BACKGROUND

I have an ical file I'd like to parse with ice cube. It has no recurring events, just a series of one off events. Those events are stored in the file as VEVENTs, where each event is a block of lines all describing a single event, starting with BEGIN:VEVENT and ending with END:VEVENT (more detail here).

CURRENT BEHAVIOUR

Icecube can't parse these events. It sees the DTSTART and DTEND inside the VEVENT, but applies them to the schedule.

EXPECTED BEHAVIOUR

I would have expected it to add each VEVENT as it's own recurrence time in the new schedule.

SOLUTION

I've refactored the ical parser such that it acts as a state machine. By default it works as it did before. However, if it sees a BEGIN:VEVENT line it goes into an event parsing mode, where it parses subsequent lines as events. Once it sees an END:VEVENT line, it goes back to the regular mode. When parsing events it adds a new recurrence time every time it sees a DTSTART.

NOTES

To keep the code simple, if there are multiple DTSTART lines within an event, it will add a new recurrence time for each of them. A VEVENT with more than one DTSTART is invalid, so this shouldn't happen in practice.
VEVENTs can have an end date (ie. DTEND) as well as a start date (DTSTART). I couldn't see a way of adding a duration to a recurrence time, so I've ignored the end dates for now.

iainbeeston · 2019-01-12T16:33:36Z

The build is failing because travis is trying to use bundler 2.0 with ruby < 2.3. #459 should fix that

lib/ice_cube/parsers/ical_parser.rb

spec/examples/from_ical_spec.rb

@seejohnrun

Will defer final approval to @seejohnrun

seejohnrun · 2021-10-25T14:05:28Z

lib/ice_cube/parsers/ical_parser.rb

+
+        parser, attr, occurrences = *send(parser, property, value)
+
+        case attr


This makes sense to me but what do you think of passing data into the parse_line and parse_vevent_line methods so that we can remove this generic case statement. I think personally it reads a bit confusing to me

That makes sense to me. Should remove an unnecessary additional case statement.

@iainbeeston - are you happy to push an update to this PR?

Sorry for the long wait, I've refactored this now to get rid of the extra case statement. Please let me know what you think.

iainbeeston force-pushed the ical-vevents branch 7 times, most recently from a5a11d7 to 318153e Compare January 16, 2019 08:58