SaberDAV fundamentals

[musonic]

Ok, I need some help getting started with SabreDAV. I feeling really
stupid at the moment, but I can't get my head around it. I've read
through the wiki over and over and followed the examples but nowhere
does it explain how to interact with the server once it is setup. It
talks about "rolling your own backends" but I don't know how to do
that in relation to my existing application. I think I have some
fundamentals mixed up that once sorted out should mean I can get
going. I should say that I think I have the server up and running.
I've added the example data to my db and when I navigate to
http:localhost:8888/myapp/sabre/index.php/ I get the directory tree
which then allows me to go into principals and calendars. That is as
far as I've got. To be clear I'm primarily interested in using
SabreDAV as a CalDAV server. I'm building a kind of event management
web app but I would like users to be able to subscribe to their
calendars in whichever calendar app they choose and to keep everything
in sync.

So here's a list of things I'm unclear about:

1) In very simple terms, how do I interact with the server? I can
authorize users ok, but I can't get any data. If I make a GET request
to http://localhost:8888/myapp/sabre/index.php/calendars/admin/default
I get an error that says "GET is only implemented on File objects".
This exception was thrown in the sabre_DAV_server class and is because
I'm not requesting an instance of the Sabre_DAV_IFile class. So, how
then do I retrieve calendar data?

2) Related to the above question, I can create new calendars by
interacting directly with the db, but how do I do this in a more
RESTful way and how to I actually store calendar data? Surely I don't
have loads of .ics files laying around?

3) I guess this is the most fundamental question that leads to most of
my misunderstanding. I know how to rewrite backend classes to provide
ways of interacting directly with the db. I've already written an
almost complete calendar system based simply on standard MVC
principals. I expected to be able to get SabreDAV to work in a RESTful
way and allow me to interact with an existing API via HTTP requests.
That way it wouldn't matter if those requests were being generated
from my web app or from iCal, for example. Have I completely
misunderstood the purpose of and how SabreDAV works?!?!?

[Evert Pot]

If you add the ICSExportPlugin, you can generate full calendars. This is not a standard caldav thing, as caldav exposes every event and task as a separate resource.
More info here:

http://code.google.com/p/sabredav/wiki/ICSExportPlugin

>
> 2) Related to the above question, I can create new calendars by
> interacting directly with the db, but how do I do this in a more
> RESTful way and how to I actually store calendar data? Surely I don't
> have loads of .ics files laying around?

Creating a new calendar is done with the MKCALENDAR http method.

http://tools.ietf.org/html/rfc4791#section-5.3.1

SabreDAV is fully based on the CalDAV specification, so any questions like these are mostly answered in the RFC. I understand it can be complex text to understand though, so if you need specific pointers, let me know.

SabreDAV 1.6.0 will allow you to create new calendars through the web interface.

>
> 3) I guess this is the most fundamental question that leads to most of
> my misunderstanding. I know how to rewrite backend classes to provide
> ways of interacting directly with the db. I've already written an
> almost complete calendar system based simply on standard MVC
> principals. I expected to be able to get SabreDAV to work in a RESTful
> way and allow me to interact with an existing API via HTTP requests.
> That way it wouldn't matter if those requests were being generated
> from my web app or from iCal, for example. Have I completely
> misunderstood the purpose of and how SabreDAV works?!?!?

If you use SabreDAV as your datastore, there is no need to rewrite the backends. You need to rewrite the backends if you are specifically interested in storing all the data in a different way.
If your just want to connect your webserver to a running SabreDAV server (or any other CalDAV server for that matter) you will need to follow the CalDAV protocol.

There's definitely some reading and researching you'll need to do to understand both WebDAV and CalDAV. A good way to get a 'feel' for how it works, is by firing up an existing client (such as Thunderbird, Evolution or iCal) and see what it's sending to the server and what it's getting back.

You basically will be implementing another client, so it's best to learn from what's out there. A good tool to see what's being sent back and forward is Charles HTTP proxy:

http://www.charlesproxy.com/

It's not free, but there's at trail that exists after 30 minutes.
Evert

[musonic]

Thanks so much for this. I've read through the specification and
that's made things alot clearer. So, the first thing I tried to check
everything was working was to make an OPTIONS request on the server
root. Unfortunately it didn't return what I was expecting. This is
what was sent:

OPTIONS /myapp/sabre/index.php HTTP/1.1
Authorization: Digest username etc etc
Host: localhost:8888
Content-Length: 0
Content-type: application/x-www-form-

And it returned a code 200 but no body.

What's going wrong?

On Jan 20, 7:46 pm, Evert Pot <evert...@gmail.com> wrote:
> On Jan 20, 2012, at 2:55 PM, musonic wrote:
>
>
>
>
>
>
>
>
>
> > Ok, I need some help getting started with SabreDAV. I feeling really
> > stupid at the moment, but I can't get my head around it. I've read
> > through the wiki over and over and followed the examples but nowhere
> > does it explain how to interact with the server once it is setup. It
> > talks about "rolling your own backends" but I don't know how to do
> > that in relation to my existing application. I think I have some
> > fundamentals mixed up that once sorted out should mean I can get
> > going. I should say that I think I have the server up and running.
> > I've added the example data to my db and when I navigate to
> > http:localhost:8888/myapp/sabre/index.php/ I get the directory tree
> > which then allows me to go into principals and calendars. That is as
> > far as I've got. To be clear I'm primarily interested in using
> > SabreDAV as a CalDAV server. I'm building a kind of event management
> > web app but I would like users to be able to subscribe to their
> > calendars in whichever calendar app they choose and to keep everything
> > in sync.
>
> > So here's a list of things I'm unclear about:
>
> > 1) In very simple terms, how do I interact with the server? I can
> > authorize users ok, but I can't get any data. If I make a GET request

> > tohttp://localhost:8888/myapp/sabre/index.php/calendars/admin/default

[Evert Pot]

On Jan 23, 2012, at 4:18 PM, musonic wrote:

> Thanks so much for this. I've read through the specification and
> that's made things alot clearer. So, the first thing I tried to check
> everything was working was to make an OPTIONS request on the server
> root. Unfortunately it didn't return what I was expecting. This is
> what was sent:
>
> OPTIONS /myapp/sabre/index.php HTTP/1.1
> Authorization: Digest username etc etc
> Host: localhost:8888
> Content-Length: 0
> Content-type: application/x-www-form-
>
> And it returned a code 200 but no body.

OPTIONS does not need to return a body. The interesting stuff coming back from an OPTIONS request is the 'Dav:' header, and the 'Allows:' header.

Evert

[musonic]

Doh! Yes, of course. All seems to be working now. :-)