Preamble
--------

This software is ready for testing by a wider audience. Some parts of
this documentation describe how features are supposed to work although
they have not been implemented yet. They are marked with [not
implemented].

There's no home page yet. Please refer to the SourceForge page instead:
    http://sourceforge.net/projects/sync4jevolution/
Because the original name "sync4jevolution" is not really appropriate,
it was changed to SyncEvolution. The web page and project name will
be changed, too.


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

SyncEvolution synchronizes Evolution's contact and calender items
[calender not implemented yet]
with a SyncML server. The items are exchanged in the vCard and
vCalender formats via the Funambol Sync4j C++ client API library,
which should make 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 directly: a SyncML server that that device and SyncEvolution
can talk to is needed. The remainder of this document assumes that
Funambol's Sync4j server bundle for Linux V2.3 was installed using the
default configuration.

With a server that fully supports SyncML and the vCard standard 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), then make 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)


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

To install SyncEvolution, just unpack an archive with a precompiled
binary for your platform in a directory of your choice. 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.

You also need a working SyncML server. If you do not have and/or
cannot get an account on an existing one, installing the Funambol
Sync4j server bundle is very easy. See:
   http://www.funambol.com/opensource/downloads.html

For Sync4j V2.3, an additional patch is recommended to preserve
line breaks of items on the server:
   http://forge.objectweb.org/tracker/index.php?func=detail&aid=304718&group_id=96&atid=300096

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
directories before running it for the first time. 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. A graphical interface via an Evolution plugin
would also be possible, but is not implemented yet. As command line
parameters SyncEvolution only supports one option which specifies the
configuration file that drives the synchronization run:

   syncevolution [<server>]

The <server> string is used to find the configuration which determines
how synchronization is going to proceed. Selection of sources of
Evolution data which are to be synchronized with that server is done
via configuration files. It is possible to configure sources without
activating their synchronization, see the "disabled" property.

If the SyncML server is not specified, SyncEvolution lists all
available Evolution backend databases.

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 databases were modified.
This is done with the "normalize_vcard" utility script described
in the "Exchanging Data" section.

In case of an 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.

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.


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 are skipped. <value> then runs until the the end of
the line. In other words, it cannot start 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 "etc/example/spds/syncml/config.txt" for options in the server
configuration and "etc/example/spds/sources/addressbook_1/config.txt"
for options in the data source configuration. Without changing this
example configuration can be used for testing the operation of
SyncEvolution, see "Exchanging Data" below.

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, so
two entries have to be added for each Evolution calendar as it stores
both events/appointments and todo items [NOT IMPLEMENTED] The Evolution data source is
determined by the type of data given in "type" and uniquely identified
with the "evolutionurl" property.

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 databases, one has
to setup two independent configurations with different "deviceId"
settings and synchronize them separately.

If the 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. [NOT IMPLEMENTED YET]


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

To support recovery from a synchronization which damaged the
local database or modified it in an unexpected way, SyncEvolution
always creates the following files during a synchronization:
- a dump of the database 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 database after the synchronization for
  automatic comparison of the before/after state with
  "normalize_vcard"

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 sring or 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, 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 probably
be lost during the next reboot.


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

SyncEvolution transmits address book entries as vCard 2.1, although
Evolution exports them as 3.0. This is done because most servers do
not yet support importing 3.0. Importing new or modified entries from
the server can be done in 2.1 and 3.0 vCards.

How the server stores the vCards depends on its implementation and
configuration. In the default Sync4j server installation, vCards are
converted into an internal format, but it preserves the Evolution
vCard extensions.

To check which data is preserved, one can use this procedure:
1. synchronize the address book with the server
2. create an new address book in Evolution
3. add a configuration for that second address book and the
   same database on the SyncML server
4. synchronize again, this time using the other data source

The "etc/localhost_1" directory contains a configuration for
a default Sync4j installation on the local host and an Evolution
address book called "syncevolution test #1". The
"etc/localhost_2" is the pendant for a second address book
called "syncevolution test #2". Both configurations can
be copied directly to ".sync4j/evolution":
  mkdir -p ~/.sync4j/evolution
  cp -a etc/localhost* ~/.sync4j/evolution
  rm -rf ~/.sync4j/evolution/localhost*/spds/sources/CVS
The last step is only necessary when working with a checkout
of the SyncEvolution sources from CVS.

For them to work, also create the two address books
  SyncEvolution test #1
  SyncEvolution test #2
inside Evolution. SyncEvolution never creates address
books itself.

Steps 1 above then becomes an invocation of
  syncevolution localhost_1
and step 4
  syncevolution localhost_2

This copies all contacts into the server and from there into the new
address book. Now one can either compare the address books in
Evolution or do that automatically:
- save the complete address books: mark all entries, save as vCard
- normalize the files with the provided Perl script:
     normalize_vcard list1.vcf >list1.normal.vcf
     normalize_vcard list2.vcf >list2.normal.vcf
- compare the normalized lists, e.g.:
     diff -c list1.normal.vcf list2.normal.vcf

Alternatively, one can invoke normalize_vcard with two file names
as arguments and it will normalize and compare them automatically
with diff in the side-by-side mode:
     normalize_vcard list1.vcf list2.vcf

Normalizing is necessary because the order of cards and their
properties as well as other minor formatting aspects may be
different. The automatic unit testing (see HACKING) also contains
a "testVCard" test which verifies the copying of contact
entries.

Modifying either address book and 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.

Did I mention that you should make backups?


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

If two clients make changes to the same item, the first one to
sync will get the server to copy its changes. 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
inside SyncEvolution: there is only an ERROR entry in the
log. A summary at the end of syncing would be better, or
even opening GUI dialogs to resolve the conflicts immediately...


Tracking Changes inside Evolution
---------------------------------

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 database server, albeit in a limited way:

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 server database that Evolution might be synchronized with.


Known Problems
--------------

ObjectWeb #<num> refers to the Funambol issue tracker at:
http://forge.objectweb.org/tracker/?group_id=96&atid=100096

- Evolution 2.0.4 and 2.4.2.1 still display the old content of a contact
  which was updated during a certain test (TestEvolution::testMerge).
  Exact reason unknown, needs to be investigated.

- refresh-server results in a Sync4j client library error at the end
  of the sync:

  TestEvolution.cpp:534:Assertion
  Test name: TestEvolution::testDeleteAll
  assertion failed
  - Expression: !res

  ObjectWeb #304806

- various vcard and special character related problems in the
  Sync4j server and client library:
  TestEvolution::testVCard fails the check that items
  are identical after copying them to the server and back
  Many of these issues have been fixed in the server already,
  but even in 2.3 plus patch some information is still lost
  (see "testing vcard conversion and copying" on the sync4j-user
   mailing list for details).
  Characters with special meaning in XML like & < > cannot be
  exchanged.

  ObjectWeb #304828, #304786, #304784, #304782

- error handling could be improved

  ObjectWeb #304805, #304562

- Removing a field and then synchronizing with the Sync4j server
  will not remove that field on the server. The server will preserve
  the old value instead.

  This is necessary because the server cannot distinguish between
  removed fields and fields that a client does not store. To avoid
  losing data when copying back items from a less capable client the
  server preserves missing fields, even in situation where the field
  was intentionally removed on the client.

  The workaround for this conceptual problem is to never clean
  (= remove) a field - better fill it with e.g. a single space.


Support
-------

If you would like to ask questions, please use the Sync4j
users mailing list. You can subscribe at
   http://sourceforge.net/mail/?group_id=30236
or mail
   sync4j-users@lists.sourceforge.net
directly. If you mail the list without subscribing, please ask
to get replies to you directly, as some people might reply
only to the list otherwise.

However, before asking a question make sure that it has not
been answered already (archives are linked to from the list
page) and is not covered in this document. There is no FAQ yet.

If you run into any kind of issue during synchronization with
SyncEvolution, please try to determine as good as you can
whether it is caused by SyncEvolution, the Sync4j client
library or the server that you talk to.

Issues in the server should be reported using the issue tracker
for it. For Sync4j, it is located at
   http://forge.objectweb.org/tracker/?group_id=96
There you can also report issues with the Sync4j client library.

Because binary releases of SyncEvolution will contain
that library and have to be updated, please also create another
issue in the SyncEvolution tracker linking to the objectweb
issue.

If unsure, just open a ticket in the SyncEvolution tracker
and it will be forwarded appropriately after an initial analysis.
That tracker is hosted at SourceForge and can also be used
for feature requests:
   http://sourceforge.net/tracker/?group_id=146288&atid=764733

Be sure to always include the following information:
- version of SyncEvolution
- version of Evolution
- server and its version
- Linux distribution
- client log if appropriate,
  server log if appropriate and available
- a description of what you do,
  what you expect to see,
  what you get instead


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

To compile the code the 3.x version of the Sync4j 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
The code was tested with Evolution 2.0.4 and 2.4.2.1. It is unclear
which other versions it is compatible with.

The build system is the normal autotools system.  See INSTALL for
general instructions how to use that and "./configure --help" for
SyncEvolution specific options. For the convenience of those checking
out from CVS directly, the files generated with "autogen.sh" are also
available from CVS.


Author
------

Patrick Ohly
patrick.ohly@gmx.de
http://ohly.home.pages.de/