All-day events take up two days in ICS feed about abe HOT 10 CLOSED

After doing a bit of digging, this issue appears to stem from this line:

event_end = str(int(event_end) + 1)

which is for some reason converting the end date from a string to an int, incrementing it, and converting back to a string. This appears to be a remnant of some code that appeared to correct the end dates for all-day events that didn't actually have a duration of one day. Removing this line gives:

BEGIN:VEVENT
SUMMARY:Olin Monday
UID:5978c6587412b80011ab8225
DESCRIPTION:Monday class schedule in effect for Olin\n\nNormal Friday sche
 dule for Babson and Wellesley classes
DTEND;VALUE=DATE:20170930
DTSTART;VALUE=DATE:20170929
LOCATION:None
TRANSP:OPAQUE
END:VEVENT

which appears to be correct. Another thing of note: this format of DTEND and DTSTART works for all-day events, but another avenue that could potentially be explored for single-day all-day events is to simply omit DTEND, which creates a single-day event as per RFC5545.

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Commenting out this line appears to correct the issue in the downloaded iCal:

from abe.

This may also have some overlap with the bug causing some (but not all) events to shift forward a minute on certain subscribed calendars:

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Dug deeper into this issue, which is primarily caused by errors with event creation on the frontend. We need to somehow fix the events already in ABE, though, and set all the seconds for all times to 00.

from abe.

@audreywl that's definitely doable, once you have a better idea of what needs to be changed we can modify the db.

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I've done some more digging, it's definitely the transfer to ics.
Using the Olin Monday that Kyle showed, the event is displayed correctly in mongodb and the GET request, but off in the iCal:

mongodb

{
  "_id": ObjectId("5978c6587412b80011ab8225"),
  "_cls": "Event",
  "title": "Olin Monday",
  "description": "Monday class schedule in effect for Olin\n\nNormal Friday schedule for Babson and Wellesley classes",
  "start": ISODate("2017-09-29T04:00:00Z"),
  "end": ISODate("2017-09-30T03:59:59Z"),
  "allDay": true,
  "visibility": "public",
  "labels": [
    "featured",
    "academic"
  ],
  "sub_events": [ ]
}

JSON from https://abe.olin.build/events/5978c6587412b80011ab8225

{
  "_cls": "Event", 
  "allDay": true, 
  "description": "Monday class schedule in effect for Olin\n\nNormal Friday schedule for Babson and Wellesley classes", 
  "end": "2017-09-30 03:59:59", 
  "id": "5978c6587412b80011ab8225", 
  "labels": [
    "featured", 
    "academic"
  ], 
  "start": "2017-09-29 04:00:00", 
  "sub_events": [], 
  "title": "Olin Monday", 
  "visibility": "public"
}

iCal downloaded from https://abe.olin.build/ics/?start=2017-09-29&end=2017-09-30

BEGIN:VEVENT
SUMMARY:Olin Monday
UID:5978c6587412b80011ab8225
DESCRIPTION:Monday class schedule in effect for Olin\n\nNormal Friday sche
 dule for Babson and Wellesley classes
DTEND;VALUE=DATE:20170931
DTSTART;VALUE=DATE:20170929
LOCATION:None
TRANSP:OPAQUE
END:VEVENT

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So is it not a rounding error? Or is it just that it's us rounding before we send the iCal? Because I saw pretty consistent behavior of anything with >30 seconds rounding to the next minute.

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If it is a rounding error, I think it should be handled on the backend.

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Omitting DTEND shouldn't break anything on the frontend. I'd vote for that route.

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Made a new branch to implement a simple fix - basically, now if an event is an all-day event that's less than a day in duration, it just omits the end date. Everything seems to work in the quick tests I did - a single-day event appears as:

BEGIN:VEVENT
SUMMARY:Olin Monday
UID:5978c6587412b80011ab8225
DESCRIPTION:Monday class schedule in effect for Olin\n\nNormal Friday sche
 dule for Babson and Wellesley classes
DTSTART;VALUE=DATE:20170929
LOCATION:None
TRANSP:OPAQUE
END:VEVENT

This event also appears normal when imported as an iCal. And multi-day all-day events still appear as:

BEGIN:VEVENT
SUMMARY:Spring Break
UID:5a760c64e8fb6d000a5fc366
DESCRIPTION:No Olin Classes
DTEND;VALUE=DATE:20180324
DTSTART;VALUE=DATE:20180319
LOCATION:None
TRANSP:OPAQUE
END:VEVENT

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