Comments on: Magic Tricks Revealed: How SyncML Works and When It Fails

By: Peter T

Peter T — Thu, 21 Jan 2010 22:13:45 +0000

Thanks for the interesting item. I’m just coming to SyncML on my N900 and finding out all the wrinkles.

By: Nico

Nico — Fri, 17 Apr 2009 17:00:27 +0000

I guess the command to create the Log Dir with Syncevolution is :

/syncevolution –configure –sync-property logdir=/home/myname/foo

Until I used this command it didn’t work.

Thanks for all this information !

By: Patrick Ohly

Patrick Ohly — Mon, 01 Dec 2008 19:04:20 +0000

Darryl, I hinted at the possibility of sending device information in the “The most intelligent servers know (= hard-coded) or detect (= by analyzing information sent by clients about themselves) which attributes a device can store.” sentence above.

This is indeed the right way to solve the problem, but it also isn’t perfect. Strictly speaking, SyncEvolution itself doesn’t know which fields Evolution supports. This might even change depending on which Evolution is running, without SyncEvolution being able to determine it (short of trying). But it’s better that SyncEvolution takes a shot at providing the information instead of the server – I really should add this.

However, when the file backend is active, how can SyncEvolution specify that all properties (including unknown X- extensions) can be stored? Isn’t the device information based on listing all supported properties, which is not possible here?

In the context of the remainder of this article it is worth pointing out that currently the Funambol server doesn’t use the information. ScheduleWorld has a special case for SyncEvolution which tells the server that SyncEvolution supports all properties; I think it uses the device information in other cases, but I’m not sure.

By: Darryl Champagne

Darryl Champagne — Fri, 28 Nov 2008 23:04:40 +0000

Just one comment about “What the server gets is a contact were certain attributes were removed. The server is not told whether it was the user who removed them (for example, removing an obsolete phone number) or whether the device was incapable of storing them. What is the poor server supposed to do?”

Which is that in theory, the client would provide accurate device information about what fields it can actually support, how many bytes fit in each, and so on.
However, there is a bit of a chicken vs. egg problem with that – many clients don’t do a good job describing themselves, so servers end up hard coding their own guesses about client capabilities, so new clients don’t generate accurate information because servers don’t use it….