path: root/README

Introduction
------------

SyncEvolution synchronizes personal information management (PIM) data
like contacts, calenders, tasks and memos via the SyncML information
synchronization standard. It supports all of these for GNOME's
Evolution and contacts for the system address book of the Nokia
Internet Tablets, Mac OS X and the iPhone. The command-line tool
'syncevolution' (compiled separately for each of these platforms)
executes the synchronization.

The items are exchanged in the vCard 2.1/3.0, iCalender 2.0 and
textual format via the open source Funambol C++ client API library,
which makes SyncEvolution compatible with the majority of SyncML
servers. Full, one-way and incremental synchronization of items are
supported.

SyncEvolution does not synchronize with another SyncML capable device
or another computer directly. A SyncML server that that device and
SyncEvolution can talk to is needed. There are several options for
that:
- using a web service like ScheduleWorld or myFUNAMBOL which store
  the data to be synchronized on a server and provide access to it
  via SyncML
- installing a SyncML server like the free one from Funambol on
  one's own server
- installing a SyncML server on the desktop


The recommended solution is ScheduleWorld because it is easier than
setting up a server and provides better support for vCard and
iCalendar data than the stock Funambol server installation. Setting up
a server on the desktop has the additional problem that not all mobile
devices can communicate with the desktop via HTTP.

All SyncML synchronization modes are supported by SyncEvolution:
- exchanging just the changes between client and server ("two-way")
- sending just the changes in one direction ("one-way-from-client/server")
- replacing all items with the ones stored in the peer
  ("refresh-from-client/server")
- a full synchronization where all items are sent to the server and
  the server then decides which items need to be deleted, added or
  updated on the client ("slow")

The remainder of this document assumes that either Funambol's
myFUNAMBOL service or ScheduleWorld are used: because ScheduleWorld is
based on the Funambol server, configuration and usage are often
similar.

With a server that fully supports SyncML and vCard/iCalender
the following works:
- copy a complete database to the server and restore it
  from the server later
- delete or modify an item locally, then make the same change
  on the server
- delete, modify or add items on the server (by synchronizing with
  another client or using a web interface), then apply the same
  change locally
- conflict resolution (where two clients modify the same item,
  then sync with the server) is handled by the server, but
  SyncEvolution has support which ensures that no data is lost
  by creating duplicates (see "Conflict Resolution" below)

For conflict resolution and synchronization between clients which
support different attributes of items the server needs an
understanding of the format of items. The Funambol server supports
that for contacts, but not yet for the calendar events and tasks that
SyncEvolution sends; see "Configuration with Funambol" below for more
information. ScheduleWorld also works with SyncEvolution for
calendars plus tasks.


Installation
------------

To install SyncEvolution, just unpack an archive with a precompiled
binary for your platform in a directory of your choice or install one
of the packages. Then create a configuration in $HOME/.sync4j/evolution
as described below under "Configuration". No special environment variables
are needed, although one might want to add the directory with contains
the "syncevolution" binary to the shell's PATH variable.

When a binary packages is not available for the target system
and/or is not up-to-date, compiling from source can also be used
to produce a binary. See below in "Compiling from Source" for details.

Although all of the features are covered by unit testing and
have been verified to work, it is highly recommended that you
make a backup of your
   $HOME/.evolution/addressbook
   $HOME/.evolution/calender
   $HOME/.evolution/tasks
   $HOME/.evolution/memos
directories before running SyncEvolution for the first time with
Evolution. In older Evolution versions the same data is found in
$HOME/evolution.


Usage
-----

Currently SyncEvolution comes as a simple command line tool which is
configured via files. The synopsis of the command line parameters is:

   syncevolution [<options>] [<server>] [<source> ...]

The <server> and the <source> strings are used to find the
configuration files which determine how synchronization is going to
proceed. Each source corresponds to one local address book, calendar,
task list or set of memos and the corresponding database on the
server.

If no arguments are given, then SyncEvolution will list all available
data sources regardless whether there is a configuration file for them
or not. The output includes the identifiers which can then be used to
select those sources in a configuration file. For each source one can
set a different synchronization mode in its configuration file.

Without the optional list of sources all sources which are enabled in
their configuration file are synchronized. Otherwise only the ones
mentioned on the command line are active. It is possible to configure
sources without activating their synchronization: if the
synchronization mode of a source is set to "none", the source will be
ignore. Explicitely listing such a source will synchronize it in
"two-way" mode once.

Progress and error messages are written into a log file that is
preserved for each synchronization run. Details about that is found
in the "Automatic Backups and Logging" section below. Immediately
before quitting SyncEvolution will show all errors or warnings
encountered and print a summary of how the local data was modified.
This is done with the "synccompare" utility script described
in the "Exchanging Data" section.

When the "logdir" option is enabled (not the default because a
persistent directory must be chosen, but highly recommended if one
has the space!), then the same comparison is also done before the
synchronization starts.

In case of a severe error the synchronization run is aborted
prematurely and SyncEvolution will return a non-zero value. Recovery
from failed synchronization is done by forcing a full synchronization
during the next run, i.e. by sending all items and letting the SyncML
server compare against the ones it already knows. This is avoided
whenever possible because matching items during a slow synchronization
can lead to duplicate entries.

After a successful synchronization the server's configuration file is
updated so that the next run can be done incrementally.  If the
configuration file has to be recreated e.g. because it was lost, the
next run recovers from that by doing a full synchronization. The risk
associated with this is that the server might not recognize items that
it already has stored previously which then would lead to duplication
of items.

The <options> in front of the server name are:

--sync|-s <mode>
  Temporarily synchronize the active sources in that mode. Useful
  for a "refresh-from-server" or "refresh-from-client" sync which
  clears all data at one end and copies all items from the other.

--status|-t
  The changes made to local data since the last synchronization are
  shown without starting a new one. This can be used to see in advance
  whether the local data needs to be synchronized with the server.

--quiet|-q
  Suppresses most of the normal output during a synchronization. The
  log file still contains all the information.

--help|-h
  Prints usage information.

--version
  Prints the SyncEvolution version.


Configuration
-------------

The configuration file of a certain <server> is stored in
   $HOME/.sync4j/evolution/<server>/spds/syncml/config.txt

The format is a simple list of
   <property> = <value>
pairs with one pair per line. Leading spaces and space around the
equals character and at the end of the line are skipped. In other words,
values can neither start or end with spaces nor contain line breaks. Do not
put quotation marks around <value>, they would be treated as part of the
value itself. Lines starting with a hash (#) after optional leading
spaces are treated as comments and skipped.

Each data source is configured in
   $HOME/.sync4j/evolution/<server>/spds/sources/<source>/config.txt

See "scheduleworld/spds/syncml/config.txt" for options in the server
configuration and "scheduleworld/spds/sources/addressbook/config.txt"
for options in the data source configuration. In packages of SyncEvolution
these files might be installed in [/usr/local]/shared/doc/syncevolution.
Another example configuration "funambol" is provided for use with a 
local Funambol installation.

Normally at least the following configuration options need to be adapted:
  spds/syncml
      syncURL
      deviceId
      username
      password
  spds/sources
      uri
      evolutionsource

Each data source corresponds to one database at the SyncML server.
The local data source is determined by the type of data given in
"type" and uniquely identified with the "evolutionsource" property.
To get a list of available data sources, run SyncEvolution with no
arguments. "evolutionsource" can be set to either the name or URL
of a data source that SyncEvolution prints then.

The "uri" property is used to identify with which database on the
SyncML server the local data is to be synchronized. Each server
usually documents what needs to be configured here. The provided
configurations for ScheduleWorld and myFUNAMBOL already have this set
correctly.

One can synchronize with multiple server databases in one run, but the
same server database can only be accessed once. To synchronize the
same server database with multiple local data sources, one
has to setup two independent configurations with different "deviceId"
settings and synchronize them separately. To create such a setup simply
copy the whole configuration tree of the server, e.g.:
  cp -r ~/.sync4j/evolution/localhost ~/.sync4j/evolution/localhost_copy
and then edit ~/.sync4j/evolution/localhost_copy/spds/syncml/config.txt
to update the "deviceId" and the sources/*/config.txt files to update
the "evolutionsource".

If an Evolution data source requires authentication, the
"evolutionuser" and "evolutionpassword" are used as credentials.
In this case the directory that contains the source's config.txt should
only be accessible by the user. Usually these fields can be left
empty.

***
*** Warning: setting evolutionuser/password in cases where it is not
*** needed as with local calendars and addressbooks can cause
*** the Evolution backend to hang.
***


Automatic Backups and Logging
-----------------------------

To support recovery from a synchronization which damaged the
local data or modified it in an unexpected way, SyncEvolution
can create the following files during a synchronization:
- a dump of the data in a format which can be imported
  back into Evolution, e.g. .vcf for address books
- a full log file with debug information
- a dump of the data after the synchronization for
  automatic comparison of the before/after state with
  "synccompare"

If the source configuration option "logdir" is set, then
a new directory will be created for each synchronization
in that directory, using the format
  SyncEvolution-<server>-<yyyy>-<mm>-<dd>-<hh>-<mm>[-<seq>]
with the various fields filled in with the time when the
synchronization started. The sequence suffix will only be
used when necessary to make the name unique. By default,
SyncEvolution will never delete any data in that log
directory unless explicitly asked to keep only a limited
number of previous log directories.

This is done by setting the "maxlogdirs" limit to something
different than the empty string and 0. If a limit is set,
then SyncEvolution will only keep that many log directories
and start removing the oldest ones when it reaches the limit.
This cleanup is only done after a successful synchronization
and is limited to directories starting with the
  SyncEvolution-<server>
prefix, so it is safe to put other files or directories
into the configured log directory.

If that option is not set (as in the example configurations),
then the directory will be created as
  $TMPDIR/SyncEvolution-<username>-<server>
with access allowed for the user only. Files from a
previous synchronization will be overwritten. This is
a lot less useful because the data will usually
be lost during the next reboot and each synchronization run
overwrites the data of the previous one.

To avoid writing any additional log file or database dumps during
a synchronization the "logdir" can be set to "none". To reduce
the verbosity of the log set "logLevel". If not set or 0, then
the verbosity is set to 3 = DEBUG when writing to a log file and
2 = INFO when writing to the console directly.


Configuration with ScheduleWorld
--------------------------------

It is recommended to sync against the new vCard 3.0 URI (card3) and
iCalendar 2.0 URIs (cal2, task2), using the "text/vcard", "text/calendar"
and "text/x-todo" type setting respectively. These are the native formats of
Evolution and a lot of effort went into ensuring that they store as
much Evolution data as possible. The "note" URI and "text/x-journal" type
can be used to synchronize memos.

SyncEvolution is primarily tested against ScheduleWorld. The
"scheduleworld" example configuration is ready to be used with these
URIs, one only has to fill in the real username and password.


Configuration with Funambol
---------------------------

A default Funambol installation already contains databases which
SyncEvolution can synchronize with Evolution address books and
calendars. They are adressed in a source config with
  uri = card
for contacts and
  uri = cal
for calendars. Tasks (aka todos) are not supported directly.

WARNING: up to and including Funambol 6.0 there are known data
conversion issues for calendars because Evolution uses iCalendar 2.0
and Funambol vCalendar 1.0.


Exchanging Data
---------------

SyncEvolution transmits address book entries as vCard 2.1 or 3.0
depending on the type chosen in the configuration. Evolution uses
3.0 internally, so SyncEvolution converts between the two formats
as needed. Calendar items and tasks have to be sent and received
in iCalendar 2.0 format. Only the UTF-8 character set is supported.

How the server stores the items depends on its implementation and
configuration. In the default Funambol server installation, contacts
and calendar items are converted into an internal format, but at
least for contacts it preserves most of the properties used by
Evolution whereas iCalendar 2.0 items are not preserved properly 
in Funambol 6.0. ScheduleWorld uses the same format as Evolution for
calendars and tasks and thus requires no conversion.

To check which data is preserved, one can use this procedure
(described for contacts, but works the same way for calendars and
tasks):
1. synchronize the address book with the server
2. create an new address book in Evolution and view it in Evolution
   once (the second step is necessary in at least Evolution 2.0.4
   to make the new address book usable in SyncEvolution)
3. add a configuration for that second address book and the
   same URI on the SyncML server
4. synchronize again, this time using the other data source

Now one can either compare the address books in Evolution or do that
automatically, described here for contacts:
- save the complete address books: mark all entries, save as vCard
- invoke synccompare with two file names as arguments and it will
  normalize and compare them automatically

Normalizing is necessary because the order of cards and their
properties as well as other minor formatting aspects may be
different. The output comes from a side-by-side comparison, but
is augmented by the script so that the context of each change
is always the complete item that was modified. Lines or items
following a ">" on the right side were added, those on the
left side followed by a "<" were removed, and those with
a "!" between text on the left and right side were modified.

The automatic unit testing (see HACKING) contains a "testItems"
test which verifies the copying of special entries using the
same method.

Modifying one of the address books or even both at the same time and
then synchronizing back and forth can be used to verify that
SyncEvolution works as expected. If you do not trust SyncEvolution or
the server, then it is prudent to run these checks with a copy of the
original address book. Make a backup of the .evolution/addressbook
directory.


Conflict Resolution
-------------------

If two clients make changes to the same item, the first one to
synchronize will copy its changes to the server. The second one
then runs into a conflict when it tries to push its own changes
into the server.

The SyncML server now has to decide how to proceed. If the server
decides to continue with its own copy and asks to overwrite the
locally modified copy (the default with Sync4j), SyncEvolution will
make a local copy first. This leads to duplicates which have to be
merged manually on the client side where the conflict
occurred. Currently there is no support for that inside SyncEvolution:
there is only an ERROR entry in the log and the summary will show
the duplicated items.

Merging items on the server is difficult because the SyncML protocol
does not specify which parts of a conflicting item were updated.
In general a server can only make more or less educated guesses
which might lead to data loss. It is better to avoid this situation
in the first place by synchronizing before making changes.


Tracking Changes inside Evolution and Nokia Internet Tablets
------------------------------------------------------------

The SyncML protocol requires that a client knows which items have been
added, modified and deleted since the last sync. This is supported by
the Evolution data server, albeit in a limited way and some backends
might not implement it:

the same function lists changes and also moves the so called "change
marker" forward. Therefore asking for changes twice in a row will only
list changes the first time and not report the same changes a second
time. SyncEvolution delays asking for changes as long as possible
and only does it when synchronization has really started. Then
if synchronization completed and items where added, modified or
deleted on behalf of the server, the change marker is moved forward.

If synchronization fails for some or all items, then SyncEvolution
cannot mark individual items for retransmission during the next
sync and forces the next sync to execute in slow mode.

The change marker that SyncEvolution uses is a string which is
composed as "SyncEvolution:<syncURL>/<name>" where <syncURL> comes
from the server config file and <name> from the source config
file. This implies that changes are tracked separately for each server
and source configuration that Evolution might be synchronized with.


Tracking Changes inside Mac OS X and iPhone
-------------------------------------------

Changes are tracked by remembering the modification time stamp
of items and comparing that list against the current list when
the next synchronization starts. Removed entries are in the first
but not the second list, added items are only in the second and
modified items have a more recent time stamp.


Known Problems + Support
------------------------

Please visit http://www.estamos.de/projects/SyncML/ for up-to-date
information about known problems and links to places where further
help can be found.


Compiling from Source
---------------------

To compile the code the 3.x version of the Funambol C++ client library
is needed. A compatible snapshot of it is included in SyncEvolution
source packages and will be used automatically. Instructions for
working with CVS sources directly are contained in the HACKING
document.

Also needed are the Evolution and libcurl development files. On
Debian 3.1 (Sarge) you can install them with:
   apt-get install libcurl3-dev evolution-data-server-dev libdb3-dev 
and optionally for the test suite:
   apt-get install libcppunit-dev

On more recent systems like Debian 4.0 (Etch) the libecal and libebook
development packages need to be installed separately and the name of
the Curl library has changed. On such a distribution the following
command installs all packages relevant SyncEvolution:
   apt-get install libcurl3-gnutls-dev evolution-data-server-dev \
                   libdb3-dev libecal1.2-dev libebook1.2-dev
The test framework is still installed with:
   apt-get install libcppunit-dev

The build system is the normal autotools system.  See INSTALL for
general instructions how to use that and "./configure --help" for
SyncEvolution specific options.


Supporting SyncEvolution
------------------------

SyncEvolution is free software: available free of charge and you have
the freedom of modifying and distributing it. If you are a software
developer, the best way to support SyncEvolution is to port it to
other backends and systems. Get in touch if you want to hear more
about this.

If you are a (hopefully happy) user of SyncEvolution, then you can
make your appreciation or suggestions for improvements known in
several ways. Although SyncEvolution is free, this does not mean that
its development did not cost much effort - quite the opposite, a lot
of time went into it.

- Send a postcard to the author (see main page).
- Leave comments on the author's blog (coming soon).
- If you really want to, you can donate an arbitrary amount of money
  via PayPal to patrick.ohly@gmx.de. This is by no means required:
  the author does not depend on this income and promises to spend it
  on SyncEvolution related expenses instead of wasting it on booze and
  women...


Author
------

Patrick Ohly
patrick.ohly@gmx.de
http://www.estamos.de/