Transferring files/large data blocks

[deepone]

I would like to be able to pass (potentially large) files between a server and client using ice... I've tried using sequence<byte> and it worked just fine at first but when the files got to a few Mbs things stopped working... (I got an unknown exception from the remote operation)

My setup is something like this:

sequence<byte> ByteData;

interface Client {

void uploadFile( string filename, ByteData data );

};

interface Server {

void login( Client* cli );

};

// in client

server->login( client );

// in server

void
ServerI::login( ClientPrx client, ..... )
{
// read file data
client->uploadFile( filename, data );
}

---

This works for small files, eg the test file I used first was 71k...
For larger files I get "Unknown exception" in the server and ClientI::uploadFile is never reached on the client...

So, is there a recommended way to do this?

[ganzuoni]

I think that you should consider a chunked transfer approach.

Something like:


sequence<byte> ByteData;

interface Receiver {

void receive( ByteData data);
void close();

};



interface Server {

Receiver *transfer( string filename);

};

Your client will send multiple chunks of the original file
invoking multiple receive() until EOF.

I have used this approach in Java and it is really ***fast***
(well, ftp is a little bit faster but....you have no objects !!)
You can experience the performances using different chunk size.
64K it is rather good.


Hope it helps,

Guido.

[marc]

Hmm... you shouldn't get an UnknownException, but instead a MemoryLimitException.

You can increase the max message size by setting the property Ice.MessageSizeMax. The default is 1024, meaning 1024 KB = 1MB. Try setting it to a larger value, like 10240 = 10MB.

For more information, have a look at the description of the MessageSizeMax property in the manual's reference section.

If you would like to see an example for transferring arbitrary long files in "chunks", have a look at the code of IcePatch in src/IcePatch.

[deepone]

Thanks... Good stuff...