lmax-exchange/nanofix

A fix client for testing FIX servers

nanofix's Issues

Functionality of blockingStart() method code of ByteChannelReader class

Gentleman,

Sorry for the form of this question (as an open issue) but it seems, it is only one possibility for me to connect you.

I have been investigating a your code, and as self training, especially in a term of Java non blocking sockets, I have decided to add SSL encapsulation to the client part of your code. I have almost completed, I can connect to my LMAX demo account, to log in using FIX message and receive response. But during code investigation, I have noticed the code of connectionEstablished() method of ChannelInitializer.java, which is called just after socket is connected (called in observer), which calls blockingStart() method of ByteChannelReader.java.

To reach my assumption (to connect my LMAX demo account) I had to comment this part of code if leaved as is - each connection is closed just after it is established. As I probably don't understand a big picture of design, my question is: what this code really does? I mean the code: Connection established observer which calls:connectionEstablished() method of:ChannelInitializer.java, which calls: inputStreamReader.blockingStart(readableByteChannel); Being precise, I don't undestand the functionality the code inside blockingStart() method.

Can you help to understand this?

Thank you in advance for each minute spent on writing a response.

Best regards,
Piotr

https://github.com/LMAX-Exchange/nanofix/blob/master/nanofix-client/src/main/java/com/lmax/nanofix/ChannelInitializer.java

@Override
public void connectionEstablished()
{
    outboundMessageSender.initialiseOutboundChannel(transport.getWritableByteChannel());
    channelReaderExecutorService.execute(new Runnable()
    {
        @Override
        public void run()
        {
            final ReadableByteChannel readableByteChannel = transport.getReadableByteChannel();
            try
            {
                inputStreamReader.blockingStart(readableByteChannel);
            }
            catch (RuntimeException e)
            {
                LOGGER.error("Exception thrown while reading from stream, channel: " + readableByteChannel, e);
            }
        }
    });
    countDownLatch.countDown();
}

https://github.com/LMAX-Exchange/nanofix/blob/master/nanofix-client/src/main/java/com/lmax/nanofix/incoming/ByteChannelReader.java

public void blockingStart(final ReadableByteChannel readableByteChannel)
{
try
{
while ((readableByteChannel.read(buffer)) != -1)
{
blocker.mayWait();
buffer.flip();
byteStreamMessageParser.parse(buffer);
buffer.clear();
}

    }
    catch (final ClosedChannelException e)
    {
        //Yes closed.
    }
    catch (final IOException e)
    {
        LOGGER.error("An error occurred trying to read from the socket", e);
    }
    finally
    {
        if (readableByteChannel != null)
        {
            try
            {
                if (readableByteChannel.isOpen())
                {
                    readableByteChannel.close();
                }
            }
            catch (IOException e)
            {
                //I don't care
            }
            connectionObserver.connectionClosed();
        }
    }
}

Invalid FIX Message Header

When using the FixMessageBuilder object, if you're building a fix message whose message type is not predefined in the MsgType object then you have to use the append() method the builder provides. If the first call to the builder is not appending the MsgType, then the fix message produced is invalid (MsgType will not be the 3rd fix tag.

Valid Message: 8=FIX.4.2|9=64|35=4|123=Y|36=10|56=tom|49=JUDD|52=20160808-12:02:50.967|34=100|10=237|

new FixMessageBuilder()
                .append(35, "4")
                .msgSeqNum(100)
                .append(123, "Y")
                .append(36, "10")
                .send();

Invalid Message: 8=FIX.4.2|9=64|34=100|123=Y|35=4|36=10|56=tom|49=JUDD|52=20160808-12:02:50.967|10=237|

new FixMessageBuilder()
                .msgSeqNum(100)
                .append(123, "Y")
                .append(35, "4")
                .append(36, "10")
                .send();

The Standard Message Header for FIX defines that MsgType should be the third field in a message (http://btobits.com/fixopaedia/fixdic44/index.html)