Category Archives: Ical RFC5545 / 2445

Notes on working with the icalendar spec:http://www.ietf.org/rfc/rfc5545.txt
(RFC2445 spec is obsolete)
More readable format here using old spec: http://www.kanzaki.com/docs/ical/

Problem with Dates/Time – Off by 1 Hour?

The dangers in choosing an events plugin without knowing whether it properly supports timezones and daylight saving. The developer may not have needed daylight saving for his country, but if you have daylight saving, or your users are intentional / across time zones, it is very important. Even if a developer has timezone support, will he/she have dealt with recurring events properly (where event recurs in one timezone, but is displayed in another… ) Continue reading

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Need to know the possible combinations for repeating dates? – an Ical cheatsheet

A “cheatsheet” page for the ical rrule for repeating events. Shows the valid combinations of “by” rules, and indicates whether they limit or expand the possible set of repeating dates for a given frequency. Continue reading

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What every developer ought to know about timezones wrt calendar files

Notes on the handling of timezones in various applications, the confusions that can result when calendar syncing, sharing, publishing etc, and some notes for developers to prevent errors. Continue reading

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Do you need BYYEARDAY for your events?

Does your group need to be able to enter events using BYYEARDAY, or is BYMONTH and BYMONTHDAY better? Continue reading

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The last week of the year is….

Negative By weeknos – so what is actually the “last week” of the year Continue reading

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What do you think is the “first week” of the year ?

Week numbers and week start days, definitions, complexity and what the plugin does Continue reading

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Paydays, Last working days and why BYSETPOS is useful

How to represent some complex recurring dates like the last business day, or last weekday in a month or year, using BYSETPOS Continue reading

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TZID’s with quotes around them

Some ics files (eg: a zimbra file)  I have encountered have the TZID enclosed in quotes. DTSTART;TZID=”America/New_York”:20080908T130000 The usual use (google calendar etc) is: DTSTART;TZID=America/New_York:20080908T130000 The spec examples do not show quotes and the quotes in the terminology definition are … Continue reading

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All day events from the previous day displaying…

A question was flagged over at wordpress I having a strange issue which I am unable to resolve (or find elsewhere). All day events of the previous day are showing up in the calendar, but other timed events from the … Continue reading

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Ical Calendar to html options

Some considerations in choosing a plugin or script to import one or more shared calendar ical feeds: Completeness and/or robustness of ical implementation? vs type of dates expected by your application. A complete implementation may of necessity be more complex … Continue reading

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