[CalendarServer-users] Questions regarding delegation, attachments and time errors

[Andre LaBranche]

> On Apr 21, 2017, at 1:34 PM, Ian Baker <ibaker at eem.ca> wrote:
> 
> ...
>>> 3) We recently hired some PC user types who are pushing us to move to Outlook and Exchange for the simple reason that they want to be able to add attachments to meeting invitations, e.g. meeting agenda. Apparently Outlook/Exchange can do this.  Is this possible using Mac’s Calendar.app and/or the WebCal client?
>> 
>> Attachments are supported in Calendar.app. Select an event, click "Attachments", then "Add attachment". Attachments are not supported in the web client.
> 
> Sorry André - color me thick, but I don’t see where to click “Attachments”.  Here is what I see when I open an event:
> 	<PastedGraphic-3.png>
> Am I looking in the wrong spot?

Here's what I see:



For some relatively recent release, client and server both switched to a new mechanism for doing attachments (called "managed attachments"). I'd guess the reason you aren't offered the option for adding attachments is a version mismatch between client and server; either the server is too old for the client or vice versa. I'm pretty sure (but not positive) that newer clients do not retain the ability to do the older attachments scheme. If the server is new enough to support managed attachments, this feature should be enabled by default. You can check by loading a calendar home in a browser, e.g. https://your-server.example.com/calendars/users/you <https://your-server.example.com/calendars/users/you>  (log in with the same credentials used for CalDAV). On the resulting page you'll see a bunch of text; do a find for managed-attachments-server-URL. If it's present, managed attachments is (are?) enabled.

Support for managed attachments can be disabled on the server, however if you do this, I'm pretty sure you will break access to any existing attachments created in the 'managed attachments' style. It may be the case that it's not possible to move from "managed attachments" back to the older style ("dropbox" - no, not "Dropbox"). As I recall, the config switch is mostly there to allow sites to delay the upgrade to managed attachments, but not for going back to dropbox once the upgrade has happened. You can check for existing attachments by querying the database; something like:

sudo psql -h /var/run/caldavd/PostgresSocket -U caldav -c "select * from attachment;"

... and you can see if the server has already performed the one-time upgrade to managed attachments by querying the 'calendarserver' table - if MANAGED-ATTACHMENTS is '1', then the attachments upgrade has already occurred.

% sudo psql -h /var/run/caldavd/PostgresSocket -U caldav -c "select * from calendarserver;"
           name           | value 
--------------------------+-------
 CALENDAR-DATAVERSION     | 6
 ADDRESSBOOK-DATAVERSION  | 2
 NOTIFICATION-DATAVERSION | 1
 MANAGED-ATTACHMENTS      | 1
 MIN-VALID-REVISION       | 29
 VERSION                  | 63

(the above output is from a slightly older-than-current CalendarServer version)

There is support for converting dropbox attachments into managed attachments as a one-time operation (typically at upgrade time), but not converting in the other direction. It may be possible to change that 1 to a 0 to allow the server to re-upgrade attachments, but that is wholly untested.

You can disable managed attachments on the server (and implicitly enable dropbox attachments) by setting

    <!-- Calendar Managed Attachments -->
    <key>EnableManagedAttachments</key>
    <false/>

in the CalendarServer config. To isolate that change from the rest of the config (some of which is automatically maintained by the UI), you can create /Library/Server/Calendar & Contacts/Config/caldavd-user.plist containing:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
  <dict>

    <!-- Calendar Managed Attachments -->
    <key>EnableManagedAttachments</key>
    <false/>

  </dict>
</plist>

... then bounce the service using the GUI switch, or: sudo calendarserver_config --restart

To reiterate, you would probably have better luck getting everything updated than trying to do any style of attachments across a sufficiently large version skew of clients.

-dre
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