Hi,
I'm trying to implement file sync over WCF and I need some guidance.
My idea was to try to modify the RCA example in Sync101 to do file sync using two FileSyncProviders. I want to instantiate one provider locally and the other inside the service and then connect them through WCF.
I think I got the philosophy right - using IFileDataRetriever etc. I also kind of managed to get the solution working but I have one problem... It seems to be related with the SyncSessionContext: the context is passed as an argument in the BeginSession method,
but since it's not serializable (it's not even fully managed code, from what I've seen) I figured I had to create my own separate session context inside the remote provider. When I do that, the call to ProcessChangeBatch on the remote FileSyncProvider throws
a ComException with the (non-)message "Operation is not valid due to the current state of the object."
For testing purposes, I then skipped WCF and ran both providers in the client but behaved as if they were separated - this allowed me some experimentation with non-serializable objects that I couldn't do over WCF. If I take the advantage of this and use
the same SyncSessionContext for both providers, it works. So, separate contexts = no go, same context (impossible over WCF) = working.
Can anyone give me a clue as to what I'm missing? Are the sync providers somehow communicating through the session context? (Hardly likely, from what I've seen - otherwise the simple custom file sync provider sample wouldn't work). Does the provider check
the state of the session and throw this exception if it missed a sync step? I also tried wiring the SyncCallbacks object in various ways so I can react to its ProgressChanged event and update progress status on the other session, but it didn't solve the problem
(or I missed the right combination). Did I also need to route other events from one to the other? If anyone is willing to take a look at my code, I'd be glad to post it somewhere for download (it's a spin-off of the Sync101 RCA sample so it shouldn't be hard
do decipher).
As an aside, I did look at the custom file provider sample for this purpose. The first problem with it is that it uses the simple provider and I don't know how to connect it with FileSyncProvider via WCF (that is, connect KnowledgeSyncProvider's RCA methods
to SimpleSyncProvider methods) - unless I run both of them locally and use WCF inside the custom provider, and I didn't know what the consequences of that would be (having to send the metadata store over WCF? etc) so I opted for FileSyncProvider on both ends.
If I was wrong (or there's a third option), please let me know.
Thanks in advance!
