Available as of Fuse Mediation Router 2.3

The netty component in Fuse Mediation Router is a socket communication component, based on the JBoss Netty community offering (available under an Apache 2.0 license). Netty is a NIO client server framework which enables quick and easy development of network applications such as protocol servers and clients. Netty greatly simplifies and streamlines network programming such as TCP and UDP socket server.

This Fuse Mediation Router component supports both producer and consumer endpoints.

The netty component has several options and allows fine-grained control of a number of TCP/UDP communication parameters (buffer sizes, keepAlives, tcpNoDelay etc) and facilitates both In-Only and In-Out communication on a Fuse Mediation Router route.

The URI scheme for a netty component is as follows

netty:tcp://localhost:99999[?options]
netty:udp://remotehost:99999/[?options]

This component supports producer and consumer endpoints for both TCP and UDP.

You can append query options to the URI in the following format, ?option=value&option=value&...

Codec Handlers and SSL Keystores can be enlisted in the Registry, such as in the Spring XML file. The values that could be passed in, are the following:

In Producer mode, the component provides the ability to send payloads to a socket endpoint using either TCP or UDP protocols (with optional SSL support).

The producer mode supports both one-way and request-response based operations.

In Consumer mode, the component provides the ability to:

The consumer mode supports both one-way and request-response based operations.

RouteBuilder builder = new RouteBuilder() {
  public void configure() {
    from("netty:udp://localhost:5155?sync=true")
      .process(new Processor() {
         public void process(Exchange exchange) throws Exception {
           Poetry poetry = (Poetry) exchange.getIn().getBody();
           poetry.setPoet("Dr. Sarojini Naidu");
           exchange.getOut().setBody(poetry);
         }
       }
    }
};

RouteBuilder builder = new RouteBuilder() {
  public void configure() {
       from("netty:tcp://localhost:5150")
           .to("mock:result"); 
  }
};

JndiRegistry registry = new JndiRegistry(createJndiContext());
registry.bind("password", "changeit");
registry.bind("ksf", new File("src/test/resources/keystore.jks"));
registry.bind("tsf", new File("src/test/resources/keystore.jks"));

context.createRegistry(registry);
context.addRoutes(new RouteBuilder() {
  public void configure() {
      String netty_ssl_endpoint = 
         "netty:tcp://localhost:5150?sync=true&ssl=true&passphrase=#password"
         + "&keyStoreFile=#ksf&trustStoreFile=#tsf";
      String return_string =
         "When You Go Home, Tell Them Of Us And Say,"
         + "For Your Tomorrow, We Gave Our Today.";
      
      from(netty_ssl_endpoint)
       .process(new Processor() {
          public void process(Exchange exchange) throws Exception {
            exchange.getOut().setBody(return_string);                           
          }
       }
  }
});

In certain cases it may be necessary to add chains of encoders and decoders to the netty pipeline. To add multpile codecs to a Fuse Mediation Router netty endpoint the 'encoders' and 'decoders' uri parameters should be used. Like the 'encoder' and 'decoder' parameters they are used to supply references (to lists of ChannelUpstreamHandlers and ChannelDownstreamHandlers) that should be added to the pipeline. Note that if encoders is specified then the encoder param will be ignored, similarly for decoders and the decoder param.

The lists of codecs need to be added to the Fuse Mediation Router's registry so they can be resolved when the endpoint is created.

LengthFieldBasedFrameDecoder lengthDecoder = new LengthFieldBasedFrameDecoder(1048576, 0, 4, 0, 4);
StringDecoder stringDecoder = new StringDecoder();
registry.bind("length-decoder", lengthDecoder);
registry.bind("string-decoder", stringDecoder);

LengthFieldPrepender lengthEncoder = new LengthFieldPrepender(4);
StringEncoder stringEncoder = new StringEncoder();
registry.bind("length-encoder", lengthEncoder);
registry.bind("string-encoder", stringEncoder);

List<ChannelUpstreamHandler> decoders = new ArrayList<ChannelUpstreamHandler>();
decoders.add(lengthDecoder);
decoders.add(stringDecoder);

List<ChannelDownstreamHandler> encoders = new ArrayList<ChannelDownstreamHandler>();
encoders.add(lengthEncoder);
encoders.add(stringEncoder);

registry.bind("encoders", encoders);
registry.bind("decoders", decoders);

Spring's native collections support can be used to specify the codec lists in an application context

    <util:list id="decoders" list-class="java.util.LinkedList">
        <bean class="org.jboss.netty.handler.codec.frame.LengthFieldBasedFrameDecoder">
            <constructor-arg value="1048576"/>
            <constructor-arg value="0"/>
            <constructor-arg value="4"/>
            <constructor-arg value="0"/>
            <constructor-arg value="4"/>
        </bean>
        <bean class="org.jboss.netty.handler.codec.string.StringDecoder"/>
    </util:list>

    <util:list id="encoders" list-class="java.util.LinkedList">
        <bean class="org.jboss.netty.handler.codec.frame.LengthFieldPrepender">
            <constructor-arg value="4"/>
        </bean>
        <bean class="org.jboss.netty.handler.codec.string.StringEncoder"/>
    </util:list>

    <bean id="length-encoder" class="org.jboss.netty.handler.codec.frame.LengthFieldPrepender">
        <constructor-arg value="4"/>
    </bean>
    <bean id="string-encoder" class="org.jboss.netty.handler.codec.string.StringEncoder"/>

    <bean id="length-decoder" class="org.jboss.netty.handler.codec.frame.LengthFieldBasedFrameDecoder">
        <constructor-arg value="1048576"/>
        <constructor-arg value="0"/>
        <constructor-arg value="4"/>
        <constructor-arg value="0"/>
        <constructor-arg value="4"/>
    </bean>
    <bean id="string-decoder" class="org.jboss.netty.handler.codec.string.StringDecoder"/>

</beans>

The bean names can then be used in netty endpoint definitions either as a comma separated list or contained in a List e.g.

                from("direct:multiple-codec").to("netty:tcp://localhost:5150?encoders=#encoders&sync=false");
                
                from("netty:tcp://localhost:5150?decoders=#length-decoder,#string-decoder&sync=false").to("mock:multiple-codec");
            }
        };
    }
}

or via spring.

<camelContext id="multiple-netty-codecs-context" xmlns="http://camel.apache.org/schema/spring">
    <route>
        <from uri="direct:multiple-codec"/>
        <to uri="netty:tcp://localhost:5150?encoders=#encoders&ync=false"/>
    </route>
    <route>
        <from uri="netty:tcp://localhost:5150?decoders=#length-decoder,#string-decoder&ync=false"/>
        <to uri="mock:multiple-codec"/>
    </route>
</camelContext>

When acting as a server you sometimes want to close the channel when, for example, a client conversion is finished. You can do this by simply setting the endpoint option disconnect=true.

However you can also instruct Fuse Mediation Router on a per message basis as follows. To instruct Fuse Mediation Router to close the channel, you should add a header with the key CamelNettyCloseChannelWhenComplete set to a boolean true value. For instance, the example below will close the channel after it has written the bye message back to the client:

        from("netty:tcp://localhost:8080").process(new Processor() {
            public void process(Exchange exchange) throws Exception {
                String body = exchange.getIn().getBody(String.class);
                exchange.getOut().setBody("Bye " + body);
                // some condition which determines if we should close
                if (close) {
                    exchange.getOut().setHeader(NettyConstants.NETTY_CLOSE_CHANNEL_WHEN_COMPLETE, true);
                }
            }
        });

Available as of Camel 2.5

Custom channel pipelines provide complete control to the user over the handler/interceptor chain by inserting custom handler(s), encoder(s) and decoders without having to specify them in the Netty Endpoint URL in a very simple way.

In order to add a custom pipeline, a custom channel pipeline factory must be created and registered with the context through the context registry (JNDIRegistry,or the Spring ApplicationContextRegistry etc).

A custom pipeline factory must be constructed as follows

The example below shows how ServerChannel Pipeline factory may be created

public class SampleServerChannelPipelineFactory extends ServerPipelineFactory {
    private int maxLineSize = 1024;
    private boolean invoked;

    public ChannelPipeline getPipeline() throws Exception {
        invoked = true;
      
        ChannelPipeline channelPipeline = Channels.pipeline();
      
        channelPipeline.addLast("encoder-SD", new StringEncoder(CharsetUtil.UTF_8));
        channelPipeline.addLast("decoder-DELIM", new DelimiterBasedFrameDecoder(maxLineSize, true, Delimiters.lineDelimiter()));
        channelPipeline.addLast("decoder-SD", new StringDecoder(CharsetUtil.UTF_8));
        channelPipeline.addLast("handler", new ServerChannelHandler(consumer));

        return channelPipeline;
    }
      
    public boolean isfactoryInvoked() {
        return invoked;
    }
}

The custom channel pipeline factory can then be added to the registry and instantiated/utilized on a camel route as follows:

Registry registry = camelContext.getRegistry();
serverPipelineFactory = new TestServerChannelPipelineFactory();
registry.bind("spf", serverPipelineFactory);
context.addRoutes(new RouteBuilder() {
    public void configure() {
        String netty_ssl_endpoint =
          "netty:tcp://localhost:5150?serverPipelineFactory=#spf";
        String return_string =
          "When You Go Home, Tell Them Of Us And Say,"
          + "For Your Tomorrow, We Gave Our Today.";
      
        from(netty_ssl_endpoint)
          .process(new Processor() {
            public void process(Exchange exchange) throws Exception {
              exchange.getOut().setBody(return_string);
            }
          }
    }
});