Hooks on the data structure/event before/after event_from_yaml

[rkdarst]

I'd be interested in a way to run hooks on the event_yaml (= loaded data structures) and event at the start/end of event_from_yaml. Would you like that feature here, and if so, do you have any suggestions for implementing it? If you would like it, I can try an initial implementation (the only major problem is "how to pass arguments into there - do we carry around hooks between all the functions, or make something global?").

My alternative option is to monkey-patch hooks in, but something clean+supported would be better... if we can find it.

(in this case, I would like to have a way to have a description_suffix that would be appended to the description. This would make template events with &label and <<: *label) cleaner... but I expect that hooks would be better than making yaml2ics too specific to my needs...

[stefanv]

Hi Richard, that could make sense. Are you thinking adding this as an argument when invoking yaml2ics as a script? And it gets the event as a string and returns it as a string?

[rkdarst]

Hm, interesting idea... I didn't think of that. So far I was just thinking through the Python API, since that's how I use it (but python API should come first anyway).

Since my entry point is files_to_calendar, to do it via arguments, the arguments would have to be passed to files_to_events and then event_from_yaml. Writing this out, I'm less confident that I can think of any maintainable way to adding this to yaml2ics, and might want to do this via monkey patching

Or... what would you say about adding a config argument to all functions, defaulting to {}, and adding hooks into there? That might be simple and elegant enough.

[stefanv]

What should the hooks do, just so I can form an idea around what's needed?

[rkdarst]

in this case my hook would be:

if 'description_suffix' in event_data:
    event_data['description'] = '\n\n'.join(event_data['description'], event_data.pop('description_suffix'))

... and maybe the equivalent for description_prefix. Even though it seems trivial, with the templating(inheritance?) in yaml I describe above, I can easily avoid repetition when making a lot of similar events.

... of course I could directly add this. On second thought, maybe it's useful for more people (except that the yaml templating isn't included in examples, I think...)

[stefanv]

Perhaps the easiest would be:

all_events, name = files_to_events(files)
[... custom postprocessing ...]
calendar = events_to_calendar(all_events)

Would that work for your use-case?