How to create an event using .ICS Files for Apple’s iCal or Microsoft’s Outlook
.ICS files allow you to be able to create small files that you can either include in an email campaign or link to on your website that will enable you to add, edit or even cancel events in people’s calendar without the requirement of them needing to fill out any of the details.
These files are commonly called iCal, vCalendar or iCalendar and often use various extensions such as .ics, .ical, .ifb & .icalendar
To create an event, the goal is to produce a small text file that contains the following:
BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Microsoft Corporation//Outlook 11.0 MIMEDIR//EN BEGIN:VEVENT UID:email@internet.com DTSTAMP:20120101T000000Z ORGANIZER;CN=SAU:MAILTO:SAU@skylinesaustralia.com DTSTART:20120715T000000Z DTEND:20120715T150000Z SUMMARY:SAUNSW Texikhana, S.O.S. proudly supported by Unigroup Engineering LOCATION:Nirimba Airfield/TAFE/Skidpan DESCRIPTION:S A U N S W - Texi, Sos, 15Th July 2012 END:VEVENT END:VCALENDAR
Breaking this code down, it’s quite simple to see what each line is doing:
BEGIN:VCALENDAR VERSION:2.0 PRODID:-//Microsoft Corporation//Outlook 11.0 MIMEDIR//EN
These 3 lines of code tell the receiving program what the following content is buy using the BEGIN code “this is a vCalendar file”. It then used VERSION to indicated the context of the following code. The PRODID is simply the name of the program that created the file and you can basically enter in what ever string you want in this section.
BEGIN:VEVENT
Indicated that this is a EVENT file and it is the beginning of the even information.
UID:email@internet.com
Is a unique identifier for this file. It is used so that you can control future actions of this even easily.
DTSTAMP:20120101T000000Z
When the file was created. (NOTE: all time are strictly 24H GMT)
ORGANIZER;CN=SAU:MAILTO:SAU@skylinesaustralia.com
Who the organiser of this event.
DTSTART:20120715T000000Z
When the event is going to start (NOTE: all time are strictly 24H GMT)
DTEND:20120715T150000Z
When the event is going to end (NOTE: all time are strictly24H GMT)
SUMMARY:SAUNSW Texikhana, S.O.S. proudly supported by Unigroup Engineering
The summary will appear in the small field in outlook and will be the content that shows when the user is viewing the calendar one of the various overview modes.
LOCATION:Nirimba Airfield/TAFE/Skidpan
Set the location of the event.
DESCRIPTION:S A U N S W - Texi, Sos, 15Th July 2012
The description is the bulk of the event content. It is where you would put all the finer details about the event like EST costs, what to bring etc.
END:VEVENT
Let the program know this is now the end the event content.
END:VCALENDAR
Let the program know this is now the end the .ics file.
Advanced
This all seems pretty basic. However, there are numerous amounts of additional commands you can include into an .ICS file that can control a lot more actions:
In an event you can inclued a VALARM command that will allow you cause the calendar application to alert the user in advanced of the event coming up.
Entering the following command inside the VEVENT will enable this
BEGIN:VALARM TRIGGER:19980403T120000 ACTION:DISPLAY DESCRIPTION:Reminder END:VALARM
This is again pretty straight forward, We have a BEGIN and END tag to describe the content contained is a VALARM, a TRIGGER which is the time to perform the reminder in YYYMMDD-T-HHMMSS (24H GMT time once again), an ACTION tag which allows you to set what to do and a DESCRIPTION where you can set what data to show the user when the reminder appears.
Updating an event
For sending an UPDATE for an event the UID should match the original UID and you should add the following tag inside theBEGIN:VEVENT in the new file
SEQUENCE:x
Where x = the upper most sequence used in the history of the event.
Cancelling an event
You can also cancel an event using the same method. Te following tags will allow the cancellation and a status message to show why it was cancelled
METHOD:CANCEL STATUS:CANCELLED
Dynamic Content
If you know a scripting language such as ASP or PHP you can create these file dynamically. To do this all you need to d is change the header’s on your .asp or .php file so that you tell your users browser that it is a .ICS file and that it should open it in the default calendar application.
PHP:
header("Content-Type: text/x-vCalendar");
header("Content-Disposition: inline; filename=july-skids.vcs");
Now you can script your file so that each area is dynamically created.
EDIT
Now with ASP headers
'construct the headers for the file to open as a vcal Response.ContentType = "text/x-vCalendar" Response.Expires = -1 Response.Buffer = True Response.Clear Response.AddHeader "Content-Disposition", "filename=vcal.vcs;" Response.Write strFileContent
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