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Posted to dev@mina.apache.org by Neill Alexander <ne...@gmail.com> on 2006/07/18 13:45:03 UTC
XML-RPC Using Mina?
I have written a custom server using Mina which handles XML requests
from clients, and sends XML responses. Version 1.0 of the server has a
very primitive (i.e. non-existent) protocol i.e. it expects a raw xml
message with no http headers etc. Since the server does not know the
length of the message up front, it must check the data as it comes in
to ensure it gets a complete xml document. As the load on the server
increases, I suspect that this will cause us performance problems.
Put this down to inexperience on my behalf when it comes to writing
servers from scratch.
I'm now looking for a good protocol to use to handle requests, and
XML-RPC looks a likely candidate. I want to investigate how difficult
it will prove to take our existing server and re-engineer it to use
XML-RPC.
Does anyone on this mailing list have any hints or tips as to how I
could go about doing this? Could I use the Apache XML-RPC library to
re-engineer the server, for example?
Any hints, tips, words of advice or warning greatly appreciated.
Thanks and regards,
Neill
[Some additional background on the server. It works in 2 modes - a
request / response mode, and also a notification mode whereby a client
can subscribe to listen for events in the system. In the notification
mode the client keeps a connection to the server open. The server
writes to this connection whenever it has information that will
interest the client.]
Re: XML-RPC Using Mina?
Posted by Neill Alexander <ne...@gmail.com>.
Thanks Maarten. That has helped me to clarify my thinking about what
protocol to use.
regards
Neill
On 7/18/06, Maarten Bosteels <mb...@gmail.com> wrote:
> I forget some clarification:
> * the decoder reads complete requests and turns them into byte arrays.
> (because I do not know the character encoding used by the document)
> * the byte array is then fed to the xml parser (xmlbeans in my case)
> * for outgoing messages, I use ByteArrayEncoder:
>
> public class ByteArrayEncoder implements ProtocolEncoder {
>
> protected final Log logger = LogFactory.getLog(getClass());
>
> public void encode(ProtocolSession session, Object message,
> ProtocolEncoderOutput out) throws ProtocolViolationException {
>
> byte[] bytes = (byte[]) message;
> int totalLength = bytes.length + 4;
> logger.debug ("encoding message with total length " + totalLength);
>
> ByteBuffer buf = ByteBuffer.allocate( totalLength );
> buf.putInt(totalLength);
> buf.put(bytes);
> buf.flip();
> out.write (buf);
> }
>
> good luck,
> Maarten
>
>
> On 7/18/06, Maarten Bosteels <mb...@gmail.com> wrote:
> >
> > Hello Neill,
> >
> > I have no experience with XML-RPC, but I have implemented an EPP server,
> > using MINA.
> > http://www.rfc-archive.org/getrfc.php?rfc=3734
> >
> > It is an request-response protocol, and both request and response are XML
> > documents.
> > The first 4 bytes of every message (both incoming and outgoing) indicates
> > the total number of bytes of the
> > message. Prefixing the message, with the length of the message is a common
> > idiom and very easy to implement.
> >
> > My implementation is still based on mina 0.8.x, so it might not be very
> > usefull to you.
> >
> > Maarten
> >
> > public class ByteArrayDecoder extends CumulativeProtocolDecoder {
> >
> > protected final Log logger = LogFactory.getLog(getClass());
> >
> > public ByteArrayDecoder() {
> > super(2048);
> > }
> >
> > protected boolean doDecode(ProtocolSession protocolSession, ByteBuffer
> > in, ProtocolDecoderOutput out) throws ProtocolViolationException {
> > int len;
> > if (in.remaining() > 4)
> > {
> > len = in.getInt();
> > int dataLength = len - 4;
> >
> > if (dataLength <= 0 || dataLength > 8000) {
> > throw new ProtocolViolationException("Invalid message length: "
> > + len);
> > }
> >
> > if (in.remaining() >= dataLength)
> > {
> > byte[] data = new byte[dataLength];
> > in.get(data);
> > out.write(data);
> > return true;
> > }
> > else
> > {
> > // put length back until message is complete
> > logger.info("put length back: " + len);
> > in.putInt(len);
> > return false;
> > }
> > }
> > else
> > {
> > return false;
> >
> > }
> > }
> > }
> >
> >
> > On 7/18/06, Neill Alexander < neillalexander@gmail.com> wrote:
> > >
> > > I have written a custom server using Mina which handles XML requests
> > > from clients, and sends XML responses. Version 1.0 of the server has a
> > > very primitive (i.e. non-existent) protocol i.e. it expects a raw xml
> > > message with no http headers etc. Since the server does not know the
> > > length of the message up front, it must check the data as it comes in
> > > to ensure it gets a complete xml document. As the load on the server
> > > increases, I suspect that this will cause us performance problems.
> > >
> > > Put this down to inexperience on my behalf when it comes to writing
> > > servers from scratch.
> > >
> > > I'm now looking for a good protocol to use to handle requests, and
> > > XML-RPC looks a likely candidate. I want to investigate how difficult
> > > it will prove to take our existing server and re-engineer it to use
> > > XML-RPC.
> > >
> > > Does anyone on this mailing list have any hints or tips as to how I
> > > could go about doing this? Could I use the Apache XML-RPC library to
> > > re-engineer the server, for example?
> > >
> > > Any hints, tips, words of advice or warning greatly appreciated.
> > >
> > > Thanks and regards,
> > >
> > >
> > > Neill
> > >
> > > [Some additional background on the server. It works in 2 modes - a
> > > request / response mode, and also a notification mode whereby a client
> > > can subscribe to listen for events in the system. In the notification
> > > mode the client keeps a connection to the server open. The server
> > > writes to this connection whenever it has information that will
> > > interest the client.]
> > >
> >
> >
>
>
Re: XML-RPC Using Mina?
Posted by Maarten Bosteels <mb...@gmail.com>.
I forget some clarification:
* the decoder reads complete requests and turns them into byte arrays.
(because I do not know the character encoding used by the document)
* the byte array is then fed to the xml parser (xmlbeans in my case)
* for outgoing messages, I use ByteArrayEncoder:
public class ByteArrayEncoder implements ProtocolEncoder {
protected final Log logger = LogFactory.getLog(getClass());
public void encode(ProtocolSession session, Object message,
ProtocolEncoderOutput out) throws ProtocolViolationException {
byte[] bytes = (byte[]) message;
int totalLength = bytes.length + 4;
logger.debug ("encoding message with total length " + totalLength);
ByteBuffer buf = ByteBuffer.allocate( totalLength );
buf.putInt(totalLength);
buf.put(bytes);
buf.flip();
out.write (buf);
}
good luck,
Maarten
On 7/18/06, Maarten Bosteels <mb...@gmail.com> wrote:
>
> Hello Neill,
>
> I have no experience with XML-RPC, but I have implemented an EPP server,
> using MINA.
> http://www.rfc-archive.org/getrfc.php?rfc=3734
>
> It is an request-response protocol, and both request and response are XML
> documents.
> The first 4 bytes of every message (both incoming and outgoing) indicates
> the total number of bytes of the
> message. Prefixing the message, with the length of the message is a common
> idiom and very easy to implement.
>
> My implementation is still based on mina 0.8.x, so it might not be very
> usefull to you.
>
> Maarten
>
> public class ByteArrayDecoder extends CumulativeProtocolDecoder {
>
> protected final Log logger = LogFactory.getLog(getClass());
>
> public ByteArrayDecoder() {
> super(2048);
> }
>
> protected boolean doDecode(ProtocolSession protocolSession, ByteBuffer
> in, ProtocolDecoderOutput out) throws ProtocolViolationException {
> int len;
> if (in.remaining() > 4)
> {
> len = in.getInt();
> int dataLength = len - 4;
>
> if (dataLength <= 0 || dataLength > 8000) {
> throw new ProtocolViolationException("Invalid message length: "
> + len);
> }
>
> if (in.remaining() >= dataLength)
> {
> byte[] data = new byte[dataLength];
> in.get(data);
> out.write(data);
> return true;
> }
> else
> {
> // put length back until message is complete
> logger.info("put length back: " + len);
> in.putInt(len);
> return false;
> }
> }
> else
> {
> return false;
>
> }
> }
> }
>
>
> On 7/18/06, Neill Alexander < neillalexander@gmail.com> wrote:
> >
> > I have written a custom server using Mina which handles XML requests
> > from clients, and sends XML responses. Version 1.0 of the server has a
> > very primitive (i.e. non-existent) protocol i.e. it expects a raw xml
> > message with no http headers etc. Since the server does not know the
> > length of the message up front, it must check the data as it comes in
> > to ensure it gets a complete xml document. As the load on the server
> > increases, I suspect that this will cause us performance problems.
> >
> > Put this down to inexperience on my behalf when it comes to writing
> > servers from scratch.
> >
> > I'm now looking for a good protocol to use to handle requests, and
> > XML-RPC looks a likely candidate. I want to investigate how difficult
> > it will prove to take our existing server and re-engineer it to use
> > XML-RPC.
> >
> > Does anyone on this mailing list have any hints or tips as to how I
> > could go about doing this? Could I use the Apache XML-RPC library to
> > re-engineer the server, for example?
> >
> > Any hints, tips, words of advice or warning greatly appreciated.
> >
> > Thanks and regards,
> >
> >
> > Neill
> >
> > [Some additional background on the server. It works in 2 modes - a
> > request / response mode, and also a notification mode whereby a client
> > can subscribe to listen for events in the system. In the notification
> > mode the client keeps a connection to the server open. The server
> > writes to this connection whenever it has information that will
> > interest the client.]
> >
>
>
Re: XML-RPC Using Mina?
Posted by Maarten Bosteels <mb...@gmail.com>.
Hello Neill,
I have no experience with XML-RPC, but I have implemented an EPP server,
using MINA.
http://www.rfc-archive.org/getrfc.php?rfc=3734
It is an request-response protocol, and both request and response are XML
documents.
The first 4 bytes of every message (both incoming and outgoing) indicates
the total number of bytes of the
message. Prefixing the message, with the length of the message is a common
idiom and very easy to implement.
My implementation is still based on mina 0.8.x, so it might not be very
usefull to you.
Maarten
public class ByteArrayDecoder extends CumulativeProtocolDecoder {
protected final Log logger = LogFactory.getLog(getClass());
public ByteArrayDecoder() {
super(2048);
}
protected boolean doDecode(ProtocolSession protocolSession, ByteBuffer in,
ProtocolDecoderOutput out) throws ProtocolViolationException {
int len;
if (in.remaining() > 4)
{
len = in.getInt();
int dataLength = len - 4;
if (dataLength <= 0 || dataLength > 8000) {
throw new ProtocolViolationException("Invalid message length: " +
len);
}
if (in.remaining() >= dataLength)
{
byte[] data = new byte[dataLength];
in.get(data);
out.write(data);
return true;
}
else
{
// put length back until message is complete
logger.info("put length back: " + len);
in.putInt(len);
return false;
}
}
else
{
return false;
}
}
}
On 7/18/06, Neill Alexander <ne...@gmail.com> wrote:
>
> I have written a custom server using Mina which handles XML requests
> from clients, and sends XML responses. Version 1.0 of the server has a
> very primitive (i.e. non-existent) protocol i.e. it expects a raw xml
> message with no http headers etc. Since the server does not know the
> length of the message up front, it must check the data as it comes in
> to ensure it gets a complete xml document. As the load on the server
> increases, I suspect that this will cause us performance problems.
>
> Put this down to inexperience on my behalf when it comes to writing
> servers from scratch.
>
> I'm now looking for a good protocol to use to handle requests, and
> XML-RPC looks a likely candidate. I want to investigate how difficult
> it will prove to take our existing server and re-engineer it to use
> XML-RPC.
>
> Does anyone on this mailing list have any hints or tips as to how I
> could go about doing this? Could I use the Apache XML-RPC library to
> re-engineer the server, for example?
>
> Any hints, tips, words of advice or warning greatly appreciated.
>
> Thanks and regards,
>
>
> Neill
>
> [Some additional background on the server. It works in 2 modes - a
> request / response mode, and also a notification mode whereby a client
> can subscribe to listen for events in the system. In the notification
> mode the client keeps a connection to the server open. The server
> writes to this connection whenever it has information that will
> interest the client.]
>