Tutorial
********

Before starting, consider if you actually need vdirsyncer. There are
better alternatives available for particular usecases.


Installation
============

See Installation.


Configuration
=============

Note:

  * The config.example from the repository contains a very terse
    version of this.

  * In this example we set up contacts synchronization, but calendar
    sync works almost the same. Just swap "type = "carddav"" for "type
    = "caldav"" and "fileext = ".vcf"" for "fileext = ".ics"".

  * Take a look at the Known Problems page if anything doesn't work
    like planned.

By default, vdirsyncer looks for its configuration file in the
following locations:

* The file pointed to by the "VDIRSYNCER_CONFIG" environment variable.

* "~/.vdirsyncer/config".

* "$XDG_CONFIG_HOME/vdirsyncer/config", which is normally
  "~/.config/vdirsyncer/config". See the XDG-Basedir specification.

The config file should start with a general section, where the only
required parameter is "status_path". The following is a minimal
example:

   [general]
   status_path = "~/.vdirsyncer/status/"

After the general section, an arbitrary amount of *pair and storage
sections* might come.

In vdirsyncer, synchronization is always done between two storages.
Such storages are defined in storage sections, and which pairs of
storages should actually be synchronized is defined in pair section.
This format is copied from OfflineIMAP, where storages are called
repositories and pairs are called accounts.

The following example synchronizes ownCloud's addressbooks to
"~/.contacts/":

   [pair my_contacts]
   a = "my_contacts_local"
   b = "my_contacts_remote"
   collections = ["from a", "from b"]

   [storage my_contacts_local]
   type = "filesystem"
   path = "~/.contacts/"
   fileext = ".vcf"

   [storage my_contacts_remote]
   type = "carddav"

   # We can simplify this URL here as well. In theory it shouldn't matter.
   url = "https://owncloud.example.com/remote.php/carddav/"
   username = "bob"
   password = "asdf"

Note:

  Configuration for other servers can be found at Servers.

After running "vdirsyncer discover" and "vdirsyncer sync",
"~/.contacts/" will contain subfolders for each addressbook, which in
turn will contain a bunch of ".vcf" files which all contain a contact
in "VCARD" format each. You can modify their contents, add new ones
and delete some [1], and your changes will be synchronized to the
CalDAV server after you run "vdirsyncer sync" again. For further
reference, it uses the storages "filesystem" and "carddav".

However, if new collections are created on the server, it will not
automatically start synchronizing those [2]. You need to run
"vdirsyncer discover" again to re-fetch this list instead.

[1] You'll want to use a helper program for this.

[2] Because collections are added rarely, and checking for this case
    before every synchronization isn't worth the overhead.


More Configuration
==================


Conflict resolution
-------------------

What if the same item is changed on both sides? What should vdirsyncer
do? Three options are currently provided:

1. vdirsyncer displays an error message (the default);

2. vdirsyncer chooses one alternative version over the other;

3. vdirsyncer starts a command of your choice that is supposed to
   merge the two alternative versions.

Options 2 and 3 require adding a ""conflict_resolution"" parameter to
the pair section. Option 2 requires giving either ""a wins"" or ""b
wins"" as value to the parameter:

   [pair my_contacts]
   ...
   conflict_resolution = "b wins"

Earlier we wrote that "b = "my_contacts_remote"", so when vdirsyncer
encounters the situation where an item changed on both sides, it will
simply overwrite the local item with the one from the server.

Option 3 requires specifying as value of ""conflict_resolution"" an
array starting with ""command"" and containing paths and arguments to
a command. For example:

   [pair my_contacts]
   ...
   conflict_resolution = ["command", "vimdiff"]

In this example, "vimdiff <a> <b>" will be called with "<a>" and "<b>"
being two temporary files containing the conflicting files. The files
need to be exactly the same when the command returns. More arguments
can be passed to the command by adding more elements to the array.

See Pair Section for the reference documentation.


Metadata synchronization
------------------------

Besides items, vdirsyncer can also synchronize metadata like the
addressbook's or calendar's "human-friendly" name (internally called
"displayname") or the color associated with a calendar. For the
purpose of explaining this feature, let's switch to a different base
example. This time we'll synchronize calendars:

   [pair my_calendars]
   a = "my_calendars_local"
   b = "my_calendars_remote"
   collections = ["from a", "from b"]
   metadata = ["color"]

   [storage my_calendars_local]
   type = "filesystem"
   path = "~/.calendars/"
   fileext = ".ics"

   [storage my_calendars_remote]
   type = "caldav"

   url = "https://owncloud.example.com/remote.php/caldav/"
   username = "bob"
   password = "asdf"

Run "vdirsyncer discover" for discovery. Then you can use "vdirsyncer
metasync" to synchronize the "color" property between your local
calendars in "~/.calendars/" and your ownCloud. Locally the color is
just represented as a file called "color" within the calendar folder.


More information about collections
----------------------------------

"Collection" is a collective term for addressbooks and calendars. A
Cardav or Caldav server can contains several "collections" which
correspond to several addressbooks or calendar.

Each collection from a storage has a "collection name", a unique
identifier for each collection. In the case of "filesystem"-storage,
this is the name of the directory that represents the collection, in
the case of the DAV-storages this is the last segment of the URL. We
use this identifier in the "collections" parameter in the
"pair"-section.

This identifier doesn't change even if you rename your calendar in
whatever UI you have, because that only changes the so-called
"displayname" property [3]. On some servers (iCloud, Google) this
identifier is randomly generated and has no correlation with the
displayname you chose.

[3] Which you can also synchronize with "metasync" using "metadata =
    ["displayname"]".

There are three collection names that have a special meaning:

* ""from a"", ""from b"": A placeholder for all collections that can
  be found on side A/B when running "vdirsyncer discover".

* "null": The parameters give to the storage are exact and require no
  discovery.

The last one requires a bit more explanation.  Assume this config
which synchronizes two directories of addressbooks:

   [pair foobar]
   a = "foo"
   b = "bar"
   collections = ["from a", "from b"]

   [storage foo]
   type = "filesystem"
   fileext = ".vcf"
   path = "./contacts_foo/"

   [storage bar]
   type = "filesystem"
   fileext = ".vcf"
   path = "./contacts_bar/"

As we saw previously this will synchronize all collections in
"./contacts_foo/" with each same-named collection in
"./contacts_bar/". If there's a collection that exists on one side but
not the other, vdirsyncer will ask whether to create that folder on
the other side.

If we set "collections = null", "./contacts_foo/" and
"./contacts_bar/" are no longer treated as folders with collections,
but as collections themselves. This means that "./contacts_foo/" and
"./contacts_bar/" will contain ".vcf"-files, not subfolders that
contain ".vcf"-files.

This is useful in situations where listing all collections fails
because your DAV-server doesn't support it, for example. In this case,
you can set "url" of your "carddav"- or "caldav"-storage to a URL that
points to your CalDAV/CardDAV collection directly.

Note that not all storages support the "null"-collection, for example
"google_contacts" and "google_calendar" don't.


Advanced collection configuration (server-to-server sync)
---------------------------------------------------------

The examples above are good enough if you want to synchronize a remote
server to a previously empty disk. However, even more trickery is
required when you have two servers with *already existing* collections
which you want to synchronize.

The core problem in this situation is that vdirsyncer pairs
collections by collection name by default (see definition in previous
section, basically a foldername or a remote UUID). When you have two
servers, those collection names may not line up as nicely. Suppose you
created two calendars "Test", one on a NextCloud server and one on
iCloud, using their respective web interfaces. The URLs look something
like this:

   NextCloud: https://example.com/remote.php/dav/calendars/user/test/
   iCloud:    https://p-XX.caldav.icloud.com/YYY/calendars/3b4c9995-5c67-4021-9fa0-be4633623e1c

Those are two DAV calendar collections. Their collection names will be
"test" and "3b4c9995-5c67-4021-9fa0-be4633623e1c" respectively, so you
don't have a single name you can address them both with. You will need
to manually "pair" (no pun intended) those collections up like this:

   [pair doublecloud]
   a = "my_nextcloud"
   b = "my_icloud"
   collections = [["mytest", "test", "3b4c9995-5c67-4021-9fa0-be4633623e1c"]]

"mytest" gives that combination of calendars a nice name you can use
when talking about it, so you would use "vdirsyncer sync
doublecloud/mytest" to say: "Only synchronize these two storages,
nothing else that may be configured".

Note:

  Why not use displaynames?You may wonder why vdirsyncer just couldn't
  figure this out by itself. After all, you did name both collections
  "Test" (which is called "the displayname"), so why not pair
  collections by that value?There are a few problems with this idea:

  * Two calendars may have the same exact displayname.

  * A calendar may not have a (non-empty) displayname.

  * The displayname might change. Either you rename the calendar, or
    the calendar renames itself because you change a language setting.

  In the end, that property was never designed to be parsed by
  machines.
