Parsing ICS instead of XML

[timoschlueter]

I am currently trying to parse the ICS file provided by Google. As @timbooo already mentioned: The XML file Google provides is plain stupid. Since day one of this App i had to parse strings into dates which is never a good idea.

I wrote a ICS parser a few years ago in python and i will try to port it to swift. I haven't found any good ICS parsers we can use out of the box so i guess we will have to do it ourselves.

Here is an example of a single event in ICS format. I think that this would be way easier to work with, especially with the timestamps.

BEGIN:VEVENT
DTSTART:20150116T163000Z
DTEND:20150116T173000Z
DTSTAMP:20150125T121641Z
UID:0nodpuvtjm8n55ncuv6kf9c4fc@google.com
CREATED:20150116T150235Z
DESCRIPTION:
LAST-MODIFIED:20150116T150235Z
LOCATION:
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:Baking Bad
TRANSP:OPAQUE
END:VEVENT

[timoschlueter]

I made some progress parsing the ICS:

30 Sekunden über Silvester: (Start: 20150117T145500Z / End: 20150117T151500Z)
Politik Simulator: (Start: 20150117T061500Z / End: 20150117T081500Z)
Almost Daily Classics: (Start: 20150117T050000Z / End: 20150117T060000Z)
RB News: (Start: 20150117T230000Z / End: 20150117T231500Z)
Stumble TV #01: (Start: 20150117T210000Z / End: 20150117T220000Z)
Shenmue 2 Das Ende: (Start: 20150117T180000Z / End: 20150117T210000Z)
Erwachsene Männer.....: (Start: 20150117T220000Z / End: 20150117T230000Z)
30 Sekunden: (Start: 20150116T173000Z / End: 20150116T180000Z)
Baking Bad: (Start: 20150116T163000Z / End: 20150116T173000Z)
Brett & Breakfast: (Start: 20150116T141500Z / End: 20150116T144500Z)

Its not a fully functional ICS parser but it extracts everything embedded inside "BEGIN:VEVENT" and "END:VEVENT". According to the RFC for ICS, the Timestamps are always the same format and in the UTC timezone.

[der-tkw]

Does the iCal contain "Pen & Paper 3" and/or "Kino +"? - It seems that the XML file doesn't. Those programs are missing, and therefore there are large gaps.

[timoschlueter]

Looks like it does:

After Dark: (Start: 20150125T103000Z / End: 20150125T120000Z)
Straight 2 Gold (SC2): (Start: 20150125T120000Z / End: 20150125T130000Z)
Schröcks Fernsehgarten: (Start: 20150125T130000Z / End: 20150125T131000Z)
-->  Pen & Paper 3: (Start: 20150125T131000Z / End: 20150125T170000Z) <--
Kino+: (Start: 20150125T170000Z / End: 20150125T190500Z)
[N] Mate Knights #2: (Start: 20150125T190500Z / End: 20150125T200000Z)
Almost Daily: (Start: 20150125T200000Z / End: 20150125T210000Z)
[N] Spiele mit Bart: (Start: 20150125T211000Z / End: 20150125T230000Z)
[L] Wir müssen Reden #2: (Start: 20150126T210000Z / End: 20150126T230000Z)

Is it visible in the plain XML file or is it a parsing error again?

[der-tkw]

I curled the URL directly and couldn't find it. Don't know the reason though.

Am 25.01.2015 um 15:56 schrieb Timo Schlüter notifications@github.com:

Looks like it does:

After Dark: (Start: 20150125T103000Z / End: 20150125T120000Z) Straight 2 Gold (SC2): (Start: 20150125T120000Z / End: 20150125T130000Z) Schröcks Fernsehgarten: (Start: 20150125T130000Z / End: 20150125T131000Z) --> Pen & Paper 3: (Start: 20150125T131000Z / End: 20150125T170000Z) <-- Kino+: (Start: 20150125T170000Z / End: 20150125T190500Z) [N] Mate Knights #2: (Start: 20150125T190500Z / End: 20150125T200000Z) Almost Daily: (Start: 20150125T200000Z / End: 20150125T210000Z) [N] Spiele mit Bart: (Start: 20150125T211000Z / End: 20150125T230000Z) [L] Wir müssen Reden #2: (Start: 20150126T210000Z / End: 20150126T230000Z) Is it visible in the plain XML file or is it a parsing error again?

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[timoschlueter]

I just committed a new version using ICS parsing: 9a2f7c9ad76be03f713fd25588f2ea1dd8d3ad35. I opened a new branch since my version may lack some features. I cleaned the code and while doing so i might have screwed up some parts of the earlier versions. Could you guys give this a review? I need a beer now :)

[BlackWolf]

Just want to add this is desperately needed, the XML seems to be majorly broken as of today, most of the program is missing for some reason. Seems to be a bug/error in google calendar, though?

I will give the ICS version a review later and report back.

[BlackWolf]

Most of it seems fine and the code is muuuch nicer now!

I do see an issue with times, though. For example, the app currently reports this:

As you can see, "Spiele mit Bart" starts at 22:10. Actually, it starts at 23:00, though, which is also what the ics seems to report. I think the app is throwing together the last show that ran and the currently running show (because Mathe Knights, which ran before, started 22:10).

I couldn't find the culprit in code, but maybe someone else can.

Besides that, code and app look great!

[timoschlueter]

Thanks for the first review and the feedback! :) I looked into the code. I imported the ICS in my OS X Kalendar and compared it to the dates you mentioned but i can't find the problem just yet.

The calendar app shots "Spiele mit Bart" starting at 22:10 and so does our app. Or am i missing something? Its late, so i may be blind :)

[BlackWolf]

You are absolutely right... I looked at the ICS in a text editor, seems I got confused ^^ In that case, no errors found :D

[timoschlueter]

Great! So i guess i will merge into master, compile a binary and update the reddit-post. With ICS under control now, the future seems a bit brighter now :D

[timoschlueter]

Fixed in 072eb22943930e818a5e2d4484f1366137f321f3.