Nevis Calendars

There are four calendar software packages installed on the Nevis web server... and three sets of calendar URLs for you to remember. This web page describes the different calendars and their uses:

Meeting-room reservations

As the name suggests, the purpose of the meeting-room reservation calendars are to reserve space in the meetings rooms at Nevis and in the Nevis Annex; there's also a "room" defined to schedule when the Nevis van will make the trip from the Columbia campus to Nevis Labs.

The use of these calendars is mostly self-explanatory. If you need any assistance, click on the Help link near the top of every page.

Here are the distinguishing features of this calendar software (the MRBS package) compared to the others discussed on this page:

• These pages are public. Everyone in the world can see them.

• Only users with an account on the Linux cluster can add, change, or delete entries on these calendars. Use the same account name and password that you use to read your mail; if you see a message about a certificate, accept it permanently.

• If a given user creates an event on one of these calendars, only that user can edit or delete that event.

Shared calendars via CalDAV

CalDAV is the same calendar system used at Google Calendars and Apple's iCloud. There's a CalDAV server at Nevis, which can be used if you want to:

• synchronize your calendars on multiple devices, such as smartphones, tablets, or different computers;
• you want to keep both private and public calendars at Nevis;
• you want to create calendars that more than one person can edit.

Creating a CalDAV calendar

For a more complete listing of how to configure calendar clients, see the DAViCal website.

Here's how to create/subscribe to calendars on the Nevis CalDAV server using iCal or BusyCal:

• In iCal, you do this by selecting "Preferences", selecting the Account pane, then hitting the "+" sign in the lower left-hand corner of the pane. In BusyCal, use the Calendar menu and select "Connect to iCloud/CalDAV server".

• The account type is "CalDAV".

• For account and password, use your standard Nevis account/mail password.

• For server name, use:

  https://calendar.nevis.columbia.edu/caldav/caldav.php/ACCOUNT/

  Don't type "ACCOUNT". Type your standard Nevis account name. For example, user jsmith would type:

  https://calendar.nevis.columbia.edu/caldav/caldav.php/jsmith/

• Hit the "Accept" button.

• If you get a dialog box about a certificate, just accept it.

• If you want to see any of the other Nevis calendars in iCal, select the "Delegation" sub-pane. At minimum, you'll probably want "Nevis Group". (In BusyCal, you don't have to do this.)

• You will not see any new calendars on the viewcal page (see below). I have to manually edit a script on the web server to make that happen. I'll do that as soon as I see that you've created a calendar of your own, or you can just send me an e-mail.

If you're using Mozilla's Sunbird, you'll have to subscribe to each calendar individually:

https://calendar.nevis.columbia.edu/caldav/caldav.php/ACCOUNT/calendar
https://calendar.nevis.columbia.edu/caldav/caldav.php/nevis/university-holidays
https://calendar.nevis.columbia.edu/caldav/caldav.php/nevis/other

Accessing a Nevis CalDAV calendar on a tablet/smartphone

There are a number of devices and operating systems, so it's hard to give a step-by-step guide. Here are the general rules:

• In iOS, you subscribe to calendars using the Setting app, then going to "Mail, Contacts, Calendars".

• Use your Nevis account name and password, no matter whose calendar you're viewing.

• The server name is calendar.nevis.columbia.edu

• Apple's iOS will incorrectly guess the location of the calendar and give you an error message. To access your Nevis calendar, go to the advanced settings and enter the URL for your calendar; e.g., https://calendar.nevis.columbia.edu/caldav/caldav.php/ACCOUNT/.

• Make sure SSL is turned on.

• Unlike iCal or BusyCal, you'll probably have to subscribe to each additional calendar individually, with a separate "account" for each one (or each group). Examples:
  • To subscribe to the Nevis holiday and general calendars, create a new account with the URL https://calendar.nevis.columbia.edu/caldav/caldav.php/nevis/
  • To subscribe to the calendar(s) for account rdoe (whether or not you're rdoe), use the URL https://calendar.nevis.columbia.edu/caldav/caldav.php/rdoe/

Multiple CalDAV calendars

When you first login to the Nevis CalDAV server, a default calendar is created for you. You can create additional calendars under your account; e.g., one for classes, one for meetings, etc. Look for a button with a "+" sign in the same screen or panel that you use to define your CalDAV account.

Some things to consider:

• Any additional calendars will not automatically show up on the viewcal page (see below). I have to manually edit a script on the web server to make that happen.
• By default, everyone with a Nevis account will able to see any additional calendars you create. If you'd like to restrict access to a given calendar, see the next section.

CalDAV access control

One of the nice features of CalDAV is you can fine-tune the access control of your calendar(s). For example, you can keep a separate calendar with a schedule of doctor's appointments, and make it visible only to you; you can create a calendar for group meetings, and allow selected people with Nevis CalDAV accounts to make their own entries into the calendar. For an example of the latter, see the "other" or "Nevis General" calendar under "Nevis Group".

The web interface for the Nevis CalDAV server is https://calendar.nevis.columbia.edu/caldav/; login with your Nevis account name and password.

You'll probably be a bit confused by the CalDAV nomenclature ("What the heck is a principle?") but eventually it begins to make sense.

Shared public calendars via WebDAV

WebDAV is an older calendar protocol which is gradually becoming obsolete, mainly because it's not as good a protocol for sharing calendars between different machines. However, it's good enough if you're only going to access your calendar with a single laptop. Among the programs that can use WebDAV are:

• Sunbird, a free program from Mozilla, the same organization that makes the web browser Firefox and the mail program Thunderbird. This calendar software is also available as an extension to Thunderbird called Lightning. There are versions of this program available for Linux, Mac OS X, and Windows.

• Apple's iCal. This program runs only on Mac OS X.

• BusyCal. This is the program I use, and I strongly recommend it.

• Microsoft Outlook can access WebDAV calendars.

To use these programs to share calendars at Nevis, you'll want to either publish your own calendar or subscribe to an existing one. For example, you can subscribe to https://calendar.nevis.columbia.edu/calendar/university-holidays.ics, which contains Columbia University holidays.

You may have to add the Nevis certificate to your system; follow the directions on this page.

Here are the distinguishing features of this calendar software (compared to the others discussed on this page):

• Only users with an account on the Linux cluster can even see these calendars. They cannot be generally viewed by the rest of the world. (Use the same account name and password that you use to read your mail; if you see a message about a certificate, accept it permanently.)

• If you want to create your own calendar files to share, you can. Just "publish" or "subscribe" to a calendar using the same naming scheme as the files above: https://www.nevis.columbia.edu/calendar/<whatever>.ics. Note that the file name must end in .ics, otherwise it will be rejected.

• By default, anyone at Nevis using Sunbird can add, modify, or delete events on any of the calendars that have been published using the above method.

• If you contact me, I can arrange for a calendar file to be restricted so only a single user (or a small number of users) can edit the calendar. However, for this kind of security, CalDAV is better (see above).

• There's a hint of "security through obscurity" here: If you don't know the name of a calendar file, you won't be able to subscribe to it. However, you can see a list of available calendars through the calendar viewing page described in the next section. Just take the name you see on that page, add https://calendar.nevis.columbia.edu/calendar/ before it, add .ics after it, and you have the name to which you can subscribe.

  If this trick doesn't work, it means the calendar is hosted by CalDAV; see above.

Viewing public calendars

If you don't have access to a computer that has a program that can edit a shared calendar, at least you can view them in a web browser. The link is http://calendar.nevis.columbia.edu/viewcal/.

Here are the distinguishing features of viewing calendars this way:

• Only users with an account on the Linux cluster can access the calendar viewer. They cannot be generally viewed by the rest of the world. (Use the same account name and password that you use to read your mail; if you see a message about a certificate, accept it permanently.)

• The navigation buttons and links are not as intuitive as I would like. (I'm using the PHP iCalendar package.)

• By default, you see everyone's calendar. You can restrict the list using the "Preferences" link on the viewer page.

• As noted above, you can only view calendars, you cannot edit them.

• If you have a calendar on any CalDAV server (Google Calendars, the Nevis server described above, etc.) it can be displayed on this page. Send me the iCal URL (available from the Shared Settings page for the calendar) and I'll include it on the list.