components/camel-netty4/src/main/docs/netty4-component.adoc

[[Netty4-NettyComponent]]
Netty Component
~~~~~~~~~~~~~~~

*Available as of Camel 2.14*

The *netty4* component in Camel is a socket communication component,
based on the http://netty.io/[Netty] project version 4. +
 Netty is a NIO client server framework which enables quick and easy
development of netwServerInitializerFactoryork applications such as
protocol servers and clients. +
 Netty greatly simplifies and streamlines network programming such as
TCP and UDP socket server.

This camel 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 Camel route.

Maven users will need to add the following dependency to their `pom.xml`
for this component:

[source,xml]
------------------------------------------------------------
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-netty4</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>
------------------------------------------------------------

[[Netty4-URIformat]]
URI format
^^^^^^^^^^

The URI scheme for a netty component is as follows

[source,java]
----------------------------------------
netty4:tcp://localhost:99999[?options]
netty4: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&...`

[[Netty4-Options]]
Options
^^^^^^^





// component options: START
The Netty4 component supports 3 options which are listed below.



{% raw %}
[width="100%",cols="2,1m,7",options="header"]
|=======================================================================
| Name | Java Type | Description
| maximumPoolSize | int | The thread pool size for the EventExecutorGroup if its in use. The default value is 16.
| configuration | NettyConfiguration | To use the NettyConfiguration as configuration when creating endpoints.
| executorService | EventExecutorGroup | To use the given EventExecutorGroup
|=======================================================================
{% endraw %}
// component options: END











// endpoint options: START
The Netty4 component supports 74 endpoint options which are listed below:

{% raw %}
[width="100%",cols="2,1,1m,1m,5",options="header"]
|=======================================================================
| Name | Group | Default | Java Type | Description
| protocol | common |  | String | *Required* The protocol to use which can be tcp or udp.
| host | common |  | String | *Required* The hostname. For the consumer the hostname is localhost or 0.0.0.0 For the producer the hostname is the remote host to connect to
| port | common |  | int | *Required* The host port number
| disconnect | common | false | boolean | Whether or not to disconnect(close) from Netty Channel right after use. Can be used for both consumer and producer.
| keepAlive | common | true | boolean | Setting to ensure socket is not closed due to inactivity
| reuseAddress | common | true | boolean | Setting to facilitate socket multiplexing
| sync | common | true | boolean | Setting to set endpoint as one-way or request-response
| tcpNoDelay | common | true | boolean | Setting to improve TCP protocol performance
| bridgeErrorHandler | consumer | false | boolean | Allows for bridging the consumer to the Camel routing Error Handler which mean any exceptions occurred while the consumer is trying to pickup incoming messages or the likes will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions that will be logged at WARN/ERROR level and ignored.
| broadcast | consumer | false | boolean | Setting to choose Multicast over UDP
| clientMode | consumer | false | boolean | If the clientMode is true netty consumer will connect the address as a TCP client.
| reconnect | consumer | true | boolean | Used only in clientMode in consumer the consumer will attempt to reconnect on disconnection if this is enabled
| reconnectInterval | consumer | 10000 | int | Used if reconnect and clientMode is enabled. The interval in milli seconds to attempt reconnection
| backlog | consumer (advanced) |  | int | Allows to configure a backlog for netty consumer (server). Note the backlog is just a best effort depending on the OS. Setting this option to a value such as 200 500 or 1000 tells the TCP stack how long the accept queue can be If this option is not configured then the backlog depends on OS setting.
| bossCount | consumer (advanced) | 1 | int | When netty works on nio mode it uses default bossCount parameter from Netty which is 1. User can use this operation to override the default bossCount from Netty
| bossGroup | consumer (advanced) |  | EventLoopGroup | Set the BossGroup which could be used for handling the new connection of the server side across the NettyEndpoint
| disconnectOnNoReply | consumer (advanced) | true | boolean | If sync is enabled then this option dictates NettyConsumer if it should disconnect where there is no reply to send back.
| exceptionHandler | consumer (advanced) |  | ExceptionHandler | To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this options is not in use. By default the consumer will deal with exceptions that will be logged at WARN/ERROR level and ignored.
| exchangePattern | consumer (advanced) |  | ExchangePattern | Sets the exchange pattern when the consumer creates an exchange.
| nettyServerBootstrapFactory | consumer (advanced) |  | NettyServerBootstrapFactory | To use a custom NettyServerBootstrapFactory
| networkInterface | consumer (advanced) |  | String | When using UDP then this option can be used to specify a network interface by its name such as eth0 to join a multicast group.
| noReplyLogLevel | consumer (advanced) | WARN | LoggingLevel | If sync is enabled this option dictates NettyConsumer which logging level to use when logging a there is no reply to send back.
| serverClosedChannelExceptionCaughtLogLevel | consumer (advanced) | DEBUG | LoggingLevel | If the server (NettyConsumer) catches an java.nio.channels.ClosedChannelException then its logged using this logging level. This is used to avoid logging the closed channel exceptions as clients can disconnect abruptly and then cause a flood of closed exceptions in the Netty server.
| serverExceptionCaughtLogLevel | consumer (advanced) | WARN | LoggingLevel | If the server (NettyConsumer) catches an exception then its logged using this logging level.
| serverInitializerFactory | consumer (advanced) |  | ServerInitializerFactory | To use a custom ServerInitializerFactory
| usingExecutorService | consumer (advanced) | true | boolean | Whether to use ordered thread pool to ensure events are processed orderly on the same channel.
| connectTimeout | producer | 10000 | int | Time to wait for a socket connection to be available. Value is in millis.
| requestTimeout | producer |  | long | Allows to use a timeout for the Netty producer when calling a remote server. By default no timeout is in use. The value is in milli seconds so eg 30000 is 30 seconds. The requestTimeout is using Netty's ReadTimeoutHandler to trigger the timeout.
| reuseChannel | producer | false | boolean | This option allows producers to reuse the same Netty Channel for the lifecycle of processing the Exchange. This is useable if you need to call a server multiple times in a Camel route and want to use the same network connection. When using this the channel is not returned to the connection pool until the Exchange is done; or disconnected if the disconnect option is set to true. The reused Channel is stored on the Exchange as an exchange property with the key link NettyConstantsNETTY_CHANNEL which allows you to obtain the channel during routing and use it as well.
| clientInitializerFactory | producer (advanced) |  | ClientInitializerFactory | To use a custom ClientInitializerFactory
| lazyChannelCreation | producer (advanced) | true | boolean | Channels can be lazily created to avoid exceptions if the remote server is not up and running when the Camel producer is started.
| producerPoolEnabled | producer (advanced) | true | boolean | Whether producer pool is enabled or not. Important: Do not turn this off as the pooling is needed for handling concurrency and reliable request/reply.
| producerPoolMaxActive | producer (advanced) | -1 | int | Sets the cap on the number of objects that can be allocated by the pool (checked out to clients or idle awaiting checkout) at a given time. Use a negative value for no limit.
| producerPoolMaxIdle | producer (advanced) | 100 | int | Sets the cap on the number of idle instances in the pool.
| producerPoolMinEvictableIdle | producer (advanced) | 300000 | long | Sets the minimum amount of time (value in millis) an object may sit idle in the pool before it is eligible for eviction by the idle object evictor.
| producerPoolMinIdle | producer (advanced) |  | int | Sets the minimum number of instances allowed in the producer pool before the evictor thread (if active) spawns new objects.
| udpConnectionlessSending | producer (advanced) | false | boolean | This option supports connection less udp sending which is a real fire and forget. A connected udp send receive the PortUnreachableException if no one is listen on the receiving port.
| useByteBuf | producer (advanced) | false | boolean | If the useByteBuf is true netty producer will turn the message body into ByteBuf before sending it out.
| allowSerializedHeaders | advanced | false | boolean | Only used for TCP when transferExchange is true. When set to true serializable objects in headers and properties will be added to the exchange. Otherwise Camel will exclude any non-serializable objects and log it at WARN level.
| bootstrapConfiguration | advanced |  | NettyServerBootstrapConfiguration | To use a custom configured NettyServerBootstrapConfiguration for configuring this endpoint.
| channelGroup | advanced |  | ChannelGroup | To use a explicit ChannelGroup.
| nativeTransport | advanced | false | boolean | Whether to use native transport instead of NIO. Native transport takes advantage of the host operating system and is only supported on some platforms. You need to add the netty JAR for the host operating system you are using. See more details at: http://netty.io/wiki/native-transports.html
| options | advanced |  | Map | Allows to configure additional netty options using option. as prefix. For example option.child.keepAlive=false to set the netty option child.keepAlive=false. See the Netty documentation for possible options that can be used.
| receiveBufferSize | advanced | 65536 | int | The TCP/UDP buffer sizes to be used during inbound communication. Size is bytes.
| receiveBufferSizePredictor | advanced |  | int | Configures the buffer size predictor. See details at Jetty documentation and this mail thread.
| sendBufferSize | advanced | 65536 | int | The TCP/UDP buffer sizes to be used during outbound communication. Size is bytes.
| synchronous | advanced | false | boolean | Sets whether synchronous processing should be strictly used or Camel is allowed to use asynchronous processing (if supported).
| transferExchange | advanced | false | boolean | Only used for TCP. You can transfer the exchange over the wire instead of just the body. The following fields are transferred: In body Out body fault body In headers Out headers fault headers exchange properties exchange exception. This requires that the objects are serializable. Camel will exclude any non-serializable objects and log it at WARN level.
| udpByteArrayCodec | advanced | false | boolean | For UDP only. If enabled the using byte array codec instead of Java serialization protocol.
| workerCount | advanced |  | int | When netty works on nio mode it uses default workerCount parameter from Netty which is cpu_core_threads2. User can use this operation to override the default workerCount from Netty
| workerGroup | advanced |  | EventLoopGroup | To use a explicit EventLoopGroup as the boss thread pool. For example to share a thread pool with multiple consumers or producers. By default each consumer or producer has their own worker pool with 2 x cpu count core threads.
| allowDefaultCodec | codec | true | boolean | The netty component installs a default codec if both encoder/deocder is null and textline is false. Setting allowDefaultCodec to false prevents the netty component from installing a default codec as the first element in the filter chain.
| autoAppendDelimiter | codec | true | boolean | Whether or not to auto append missing end delimiter when sending using the textline codec.
| decoder | codec |  | ChannelHandler | A custom ChannelHandler class that can be used to perform special marshalling of inbound payloads.
| decoderMaxLineLength | codec | 1024 | int | The max line length to use for the textline codec.
| decoders | codec |  | String | A list of decoders to be used. You can use a String which have values separated by comma and have the values be looked up in the Registry. Just remember to prefix the value with so Camel knows it should lookup.
| delimiter | codec | LINE | TextLineDelimiter | The delimiter to use for the textline codec. Possible values are LINE and NULL.
| encoder | codec |  | ChannelHandler | A custom ChannelHandler class that can be used to perform special marshalling of outbound payloads.
| encoders | codec |  | String | A list of encoders to be used. You can use a String which have values separated by comma and have the values be looked up in the Registry. Just remember to prefix the value with so Camel knows it should lookup.
| encoding | codec |  | String | The encoding (a charset name) to use for the textline codec. If not provided Camel will use the JVM default Charset.
| textline | codec | false | boolean | Only used for TCP. If no codec is specified you can use this flag to indicate a text line based codec; if not specified or the value is false then Object Serialization is assumed over TCP.
| enabledProtocols | security | TLSv1,TLSv1.1,TLSv1.2 | String | Which protocols to enable when using SSL
| keyStoreFile | security |  | File | Client side certificate keystore to be used for encryption
| keyStoreFormat | security |  | String | Keystore format to be used for payload encryption. Defaults to JKS if not set
| keyStoreResource | security |  | String | Client side certificate keystore to be used for encryption. Is loaded by default from classpath but you can prefix with classpath: file: or http: to load the resource from different systems.
| needClientAuth | security | false | boolean | Configures whether the server needs client authentication when using SSL.
| passphrase | security |  | String | Password setting to use in order to encrypt/decrypt payloads sent using SSH
| securityProvider | security |  | String | Security provider to be used for payload encryption. Defaults to SunX509 if not set.
| ssl | security | false | boolean | Setting to specify whether SSL encryption is applied to this endpoint
| sslClientCertHeaders | security | false | boolean | When enabled and in SSL mode then the Netty consumer will enrich the Camel Message with headers having information about the client certificate such as subject name issuer name serial number and the valid date range.
| sslContextParameters | security |  | SSLContextParameters | To configure security using SSLContextParameters
| sslHandler | security |  | SslHandler | Reference to a class that could be used to return an SSL Handler
| trustStoreFile | security |  | File | Server side certificate keystore to be used for encryption
| trustStoreResource | security |  | String | Server side certificate keystore to be used for encryption. Is loaded by default from classpath but you can prefix with classpath: file: or http: to load the resource from different systems.
|=======================================================================
{% endraw %}
// endpoint options: END







[[Netty4-RegistrybasedOptions]]
Registry based Options
^^^^^^^^^^^^^^^^^^^^^^

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

[width="100%",cols="10%,90%",options="header",]
|=======================================================================
|Name |Description

|`passphrase` |password setting to use in order to encrypt/decrypt payloads sent using
SSH

|`keyStoreFormat` |keystore format to be used for payload encryption. Defaults to "JKS" if
not set

|`securityProvider` |Security provider to be used for payload encryption. Defaults to
"SunX509" if not set.

|`keyStoreFile` |*deprecated:* Client side certificate keystore to be used for encryption

|`trustStoreFile` |*deprecated:* Server side certificate keystore to be used for encryption

|`keyStoreResource` |*Camel 2.11.1:* Client side certificate keystore to be used for
encryption. Is loaded by default from classpath, but you can prefix with
`"classpath:"`, `"file:"`, or `"http:"` to load the resource from
different systems.

|`trustStoreResource` |*Camel 2.11.1:* Server side certificate keystore to be used for
encryption. Is loaded by default from classpath, but you can prefix with
`"classpath:"`, `"file:"`, or `"http:"` to load the resource from
different systems.

|`sslHandler` |Reference to a class that could be used to return an SSL Handler

|`encoder` |A custom `ChannelHandler` class that can be used to perform special
marshalling of outbound payloads. Must override
io.netty.channel.ChannelInboundHandlerAdapter.

|`encoders` |A list of encoders to be used. You can use a String which have values
separated by comma, and have the values be looked up in the
link:registry.html[Registry]. Just remember to prefix the value with #
so Camel knows it should lookup.

|`decoder` |A custom `ChannelHandler` class that can be used to perform special
marshalling of inbound payloads. Must override
io.netty.channel.ChannelOutboundHandlerAdapter.

|`decoders` |A list of decoders to be used. You can use a String which have values
separated by comma, and have the values be looked up in the
link:registry.html[Registry]. Just remember to prefix the value with #
so Camel knows it should lookup.
|=======================================================================

*Important:* Read below about using non shareable encoders/decoders.

[[Netty4-Usingnonshareableencodersordecoders]]
Using non shareable encoders or decoders
++++++++++++++++++++++++++++++++++++++++

If your encoders or decoders is not shareable (eg they have the
@Shareable class annotation), then your encoder/decoder must implement
the `org.apache.camel.component.netty.ChannelHandlerFactory` interface,
and return a new instance in the `newChannelHandler` method. This is to
ensure the encoder/decoder can safely be used. If this is not the case,
then the Netty component will log a WARN when +
 an endpoint is created.

The Netty component offers a
`org.apache.camel.component.netty.ChannelHandlerFactories` factory
class, that has a number of commonly used methods.

[[Netty4-SendingMessagestofromaNettyendpoint]]
Sending Messages to/from a Netty endpoint
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[[Netty4-NettyProducer]]
Netty Producer
++++++++++++++

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.

[[Netty4-NettyConsumer]]
Netty Consumer
++++++++++++++

In Consumer mode, the component provides the ability to:

* listen on a specified socket using either TCP or UDP protocols (with
optional SSL support),
* receive requests on the socket using text/xml, binary and serialized
object based payloads and
* send them along on a route as message exchanges.

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

[[Netty4-UsageSamples]]
Usage Samples
^^^^^^^^^^^^^

[[Netty4-AUDPNettyendpointusingRequest-Replyandserializedobjectpayload]]
A UDP Netty endpoint using Request-Reply and serialized object payload
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

[source,java]
------------------------------------------------------------------
RouteBuilder builder = new RouteBuilder() {
  public void configure() {
    from("netty4: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);
         }
       }
    }
};
------------------------------------------------------------------

[[Netty4-ATCPbasedNettyconsumerendpointusingOne-waycommunication]]
A TCP based Netty consumer endpoint using One-way communication
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

[source,java]
-------------------------------------------
RouteBuilder builder = new RouteBuilder() {
  public void configure() {
       from("netty4:tcp://localhost:5150")
           .to("mock:result");
  }
};
-------------------------------------------

[[Netty4-AnSSLTCPbasedNettyconsumerendpointusingRequest-Replycommunication]]
An SSL/TCP based Netty consumer endpoint using Request-Reply communication
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

[[Netty4-UsingtheJSSEConfigurationUtility]]
Using the JSSE Configuration Utility

As of Camel 2.9, the Netty component supports SSL/TLS configuration
through the link:camel-configuration-utilities.html[Camel JSSE
Configuration Utility].  This utility greatly decreases the amount of
component specific code you need to write and is configurable at the
endpoint and component levels.  The following examples demonstrate how
to use the utility with the Netty component.

[[Netty4-Programmaticconfigurationofthecomponent]]
Programmatic configuration of the component

[source,java]
------------------------------------------------------------------------------------------
KeyStoreParameters ksp = new KeyStoreParameters();
ksp.setResource("/users/home/server/keystore.jks");
ksp.setPassword("keystorePassword");

KeyManagersParameters kmp = new KeyManagersParameters();
kmp.setKeyStore(ksp);
kmp.setKeyPassword("keyPassword");

SSLContextParameters scp = new SSLContextParameters();
scp.setKeyManagers(kmp);

NettyComponent nettyComponent = getContext().getComponent("netty4", NettyComponent.class);
nettyComponent.setSslContextParameters(scp);
------------------------------------------------------------------------------------------

[[Netty4-SpringDSLbasedconfigurationofendpoint]]
Spring DSL based configuration of endpoint

[source,xml]
-------------------------------------------------------------------------------------------------------
...
  <camel:sslContextParameters
      id="sslContextParameters">
    <camel:keyManagers
        keyPassword="keyPassword">
      <camel:keyStore
          resource="/users/home/server/keystore.jks"
          password="keystorePassword"/>
    </camel:keyManagers>
  </camel:sslContextParameters>...
...
  <to uri="netty4:tcp://localhost:5150?sync=true&ssl=true&sslContextParameters=#sslContextParameters"/>
...
-------------------------------------------------------------------------------------------------------

[[Netty4-UsingBasicSSL/TLSconfigurationontheJettyComponent]]
Using Basic SSL/TLS configuration on the Jetty Component

[source,java]
------------------------------------------------------------------------------
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 =
         "netty4: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);
          }
       }
  }
});
------------------------------------------------------------------------------

[[Netty4-GettingaccesstoSSLSessionandtheclientcertificate]]
Getting access to SSLSession and the client certificate

*Available as of Camel 2.12*

You can get access to the `javax.net.ssl.SSLSession` if you eg need to
get details about the client certificate. When `ssl=true` then the
link:netty4.html[Netty4] component will store the `SSLSession` as a
header on the Camel link:message.html[Message] as shown below:

[source,java]
----------------------------------------------------------------------------------------------------
SSLSession session = exchange.getIn().getHeader(NettyConstants.NETTY_SSL_SESSION, SSLSession.class);
// get the first certificate which is client certificate
javax.security.cert.X509Certificate cert = session.getPeerCertificateChain()[0];
Principal principal = cert.getSubjectDN();
----------------------------------------------------------------------------------------------------

Remember to set `needClientAuth=true` to authenticate the client,
otherwise `SSLSession` cannot access information about the client
certificate, and you may get an exception
`javax.net.ssl.SSLPeerUnverifiedException: peer not authenticated`. You
may also get this exception if the client certificate is expired or not
valid etc.

TIP: The option `sslClientCertHeaders` can be set to `true` which then
enriches the Camel link:message.html[Message] with headers having
details about the client certificate. For example the subject name is
readily available in the header `CamelNettySSLClientCertSubjectName`.

[[Netty4-UsingMultipleCodecs]]
Using Multiple Codecs
+++++++++++++++++++++

In certain cases it may be necessary to add chains of encoders and
decoders to the netty pipeline. To add multpile codecs to a camel 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.

INFO: Read further above about using non shareable encoders/decoders.

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

[source,java]
-------------------------------------------------------------------------------------------------------------------
ChannelHandlerFactory lengthDecoder = ChannelHandlerFactories.newLengthFieldBasedFrameDecoder(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<ChannelHandler> decoders = new ArrayList<ChannelHandler>();
decoders.add(lengthDecoder);
decoders.add(stringDecoder);
 
List<ChannelHandler> encoders = new ArrayList<ChannelHandler>();
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

[source,java]
-------------------------------------------------------------------------------------------------------------------------------------------------
   
<util:list id="decoders" list-class="java.util.LinkedList">
        <bean class="org.apache.camel.component.netty4.ChannelHandlerFactories" factory-method="newLengthFieldBasedFrameDecoder">
            <constructor-arg value="1048576"/>
            <constructor-arg value="0"/>
            <constructor-arg value="4"/>
            <constructor-arg value="0"/>
            <constructor-arg value="4"/>
        </bean>
        <bean class="io.netty.handler.codec.string.StringDecoder"/>
    </util:list>

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

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

    <bean id="length-decoder" class="org.apache.camel.component.netty4.ChannelHandlerFactories" factory-method="newLengthFieldBasedFrameDecoder">
        <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="io.netty.handler.codec.string.StringDecoder"/>
-------------------------------------------------------------------------------------------------------------------------------------------------

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

[source,java]
-----------------------------------------------------------------------------------------------------------------------
 from("direct:multiple-codec").to("netty4:tcp://localhost:{{port}}?encoders=#encoders&sync=false");
                
 from("netty4:tcp://localhost:{{port}}?decoders=#length-decoder,#string-decoder&sync=false").to("mock:multiple-codec");
-----------------------------------------------------------------------------------------------------------------------

or via spring.

[source,java]
-------------------------------------------------------------------------------------------------------------
   <camelContext id="multiple-netty-codecs-context" xmlns="http://camel.apache.org/schema/spring">
        <route>
            <from uri="direct:multiple-codec"/>
            <to uri="netty4:tcp://localhost:5150?encoders=#encoders&amp;sync=false"/>
        </route>
        <route>
            <from uri="netty4:tcp://localhost:5150?decoders=#length-decoder,#string-decoder&amp;sync=false"/>
            <to uri="mock:multiple-codec"/>
        </route>
    </camelContext>
-------------------------------------------------------------------------------------------------------------

[[Netty4-ClosingChannelWhenComplete]]
Closing Channel When Complete
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

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 Camel on a per message basis as follows. +
 To instruct Camel 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:

[source,java]
--------------------------------------------------------------------------------------------------------
        from("netty4: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);
                }
            }
        });
--------------------------------------------------------------------------------------------------------

[[Netty4-Addingcustomchannelpipelinefactoriestogaincompletecontroloveracreatedpipeline]]
Adding custom channel pipeline factories to gain complete control over a
created pipeline
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Custom channel pipelines provide complete control to the user over the
handler/interceptor chain by inserting custom handler(s), encoder(s) &
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 via the context registry
(JNDIRegistry,or the camel-spring ApplicationContextRegistry etc).

A custom pipeline factory must be constructed as follows

* A Producer linked channel pipeline factory must extend the abstract
class `ClientPipelineFactory`.
* A Consumer linked channel pipeline factory must extend the abstract
class `ServerInitializerFactory`.
* The classes should override the initChannel() method in order to
insert custom handler(s), encoder(s) and decoder(s). Not overriding the
initChannel() method creates a pipeline with no handlers, encoders or
decoders wired to the pipeline.

The example below shows how ServerInitializerFactory factory may be
created

*Using custom pipeline factory*

[source,java]
--------------------------------------------------------------------------------------------------------------------------------
public class SampleServerInitializerFactory extends ServerInitializerFactory {
    private int maxLineSize = 1024;

     protected void initChannel(Channel ch) throws Exception {
        ChannelPipeline channelPipeline = ch.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));
        // here we add the default Camel ServerChannelHandler for the consumer, to allow Camel to route the message etc.
        channelPipeline.addLast("handler", new ServerChannelHandler(consumer));
    }
}
--------------------------------------------------------------------------------------------------------------------------------

The custom channel pipeline factory can then be added to the registry
and instantiated/utilized on a camel route in the following way

[source,java]
----------------------------------------------------------------------
Registry registry = camelContext.getRegistry();
ServerInitializerFactory factory = new TestServerInitializerFactory();
registry.bind("spf", factory);
context.addRoutes(new RouteBuilder() {
  public void configure() {
      String netty_ssl_endpoint =
         "netty4:tcp://localhost:5150?serverInitializerFactory=#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);
          }
       }
  }
});
----------------------------------------------------------------------

[[Netty4-ReusingNettybossandworkerthreadpools]]
Reusing Netty boss and worker thread pools
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

*Available as of Camel 2.12*

Netty has two kind of thread pools: boss and worker. By default each
Netty consumer and producer has their private thread pools. If you want
to reuse these thread pools among multiple consumers or producers then
the thread pools must be created and enlisted in the
link:registry.html[Registry].

For example using Spring XML we can create a shared worker thread pool
using the `NettyWorkerPoolBuilder` with 2 worker threads as shown below:

[source,xml]
-----------------------------------------------------------------------------------------
  <!-- use the worker pool builder to create to help create the shared thread pool -->
  <bean id="poolBuilder" class="org.apache.camel.component.netty.NettyWorkerPoolBuilder">
    <property name="workerCount" value="2"/>
  </bean>

  <!-- the shared worker thread pool -->
  <bean id="sharedPool" class="org.jboss.netty.channel.socket.nio.WorkerPool"
        factory-bean="poolBuilder" factory-method="build" destroy-method="shutdown">
  </bean>
-----------------------------------------------------------------------------------------

TIP: For boss thread pool there is a
`org.apache.camel.component.netty4.NettyServerBossPoolBuilder` builder
for Netty consumers, and a
`org.apache.camel.component.netty4.NettyClientBossPoolBuilder` for the
Netty produces.

Then in the Camel routes we can refer to this worker pools by
configuring the `workerPool` option in the
https://cwiki.apache.org/confluence/pages/createpage.action?spaceKey=CAMEL&title=URI&linkCreation=true&fromPageId=45877614[URI]
as shown below:

[source,xml]
-------------------------------------------------------------------------------------------------------------------------------------
    <route>
      <from uri="netty4:tcp://localhost:5021?textline=true&amp;sync=true&amp;workerPool=#sharedPool&amp;usingExecutorService=false"/>
      <to uri="log:result"/>
      ...
    </route>
-------------------------------------------------------------------------------------------------------------------------------------

And if we have another route we can refer to the shared worker pool:

[source,xml]
-------------------------------------------------------------------------------------------------------------------------------------
    <route>
      <from uri="netty4:tcp://localhost:5022?textline=true&amp;sync=true&amp;workerPool=#sharedPool&amp;usingExecutorService=false"/>
      <to uri="log:result"/>
      ...
    </route>
-------------------------------------------------------------------------------------------------------------------------------------

... and so forth.

[[Netty4-SeeAlso]]
See Also
^^^^^^^^

* link:configuring-camel.html[Configuring Camel]
* link:component.html[Component]
* link:endpoint.html[Endpoint]
* link:getting-started.html[Getting Started]

* link:netty-http.html[Netty HTTP]
* link:mina.html[MINA]