Add article about recurring events
This commit is contained in:
parent
32924598a9
commit
2ed1e51e64
37
_posts/2018-07-19-recurring-events.md
Normal file
37
_posts/2018-07-19-recurring-events.md
Normal file
@ -0,0 +1,37 @@
|
||||
---
|
||||
layout: post
|
||||
title: "Recurring events are hard"
|
||||
date: 2018-07-19 13:22:00
|
||||
tags: [development]
|
||||
published: true
|
||||
author:
|
||||
name: Gergely Polonkai
|
||||
email: gergely@polonkai.eu
|
||||
---
|
||||
|
||||
It was almost a month ago when I
|
||||
[announced]({% post_url 2018-06-26-please-welcome-calendar-social %}) the development of
|
||||
Calendar.social. Since then I’m over some interesting and some less interesting stuff; (web)
|
||||
development, after all, is just a recurrence of patterns. Speaking of recurrence, I arrived to a
|
||||
really interesting topic: recurring events.
|
||||
|
||||
My initial thought was like “oh, that’s easy! Let’s insert all future occurences as a separate
|
||||
`Event` object, linking to the original one for the details. That makes handling exceptions easy,
|
||||
as I just have to update/delete that specific instance.” Well, not really. I mean, an event
|
||||
repeating daily *forever* would fill up the database quickly, isn’t it? That’s when I decided to
|
||||
look how other projects do it.
|
||||
|
||||
As it turns out, my first thought is about the same as everyone else has their mind, with about
|
||||
the same reasons. Then, they usually turn down the idea just like I did. And instead, they
|
||||
implement recurrence patterns and exception patterns.
|
||||
|
||||
My favourite is
|
||||
[this article](https://github.com/bmoeskau/Extensible/blob/master/recurrence-overview.md) so far.
|
||||
The author suggests to use the recurrence patterns specced by
|
||||
[RFC2445](http://www.ietf.org/rfc/rfc2445.txt) (the spec for the iCalendar format). The
|
||||
interesting part in this solution is how to query recurring events: you simply store the timestamp
|
||||
of the last occurence of the events (or, if the event repeats forever, the greatest timestamp your
|
||||
database supports.)
|
||||
|
||||
Choosing the maximum date seemed to be the tricky one, but it turned out both Python and popular
|
||||
SQL backends support dates up to the end of year 9999.
|
Loading…
Reference in New Issue
Block a user