[[Cometd-CometdComponent]]
Cometd Component
~~~~~~~~~~~~~~~~

The *cometd:* component is a transport for working with the
http://www.mortbay.org/jetty[jetty] implementation of the
http://docs.codehaus.org/display/JETTY/Cometd+%28aka+Bayeux%29[cometd/bayeux
protocol]. +
 Using this component in combination with the dojo toolkit library it's
possible to push Camel messages directly into the browser using an AJAX
based mechanism.

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-cometd</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>
------------------------------------------------------------

[[Cometd-URIformat]]
URI format
^^^^^^^^^^

[source,java]
----------------------------------------
cometd://host:port/channelName[?options]
----------------------------------------

The *channelName* represents a topic that can be subscribed to by the
Camel endpoints.

[[Cometd-Examples]]
Examples
^^^^^^^^

------------------------------------------
cometd://localhost:8080/service/mychannel
cometds://localhost:8443/service/mychannel
------------------------------------------

where `cometds:` represents an SSL configured endpoint.

[[Cometd-Options]]
Options
^^^^^^^
[width="100%",cols="10%,10%,80%",options="header",]
|=======================================================================
|Name |Default Value |Description

|`resourceBase` |  | The root directory for the web resources or classpath. Use the protocol
file: or classpath: depending if you want that the component loads the
resource from file system or classpath. Classpath is required for OSGI
deployment where the resources are packaged in the jar. Notice this
option has been renamed to `baseResource` from *Camel 2.7* onwards.

|`baseResource` |  | *Camel 2.7:* The root directory for the web resources or classpath. Use
the protocol file: or classpath: depending if you want that the
component loads the resource from file system or classpath. Classpath is
required for OSGI deployment where the resources are packaged in the jar

|`timeout` |`240000` |The server side poll timeout in milliseconds. This is how long the
server will hold a reconnect request before responding.

|`interval` |`0` |The client side poll timeout in milliseconds. How long a client will
wait between reconnects

|`maxInterval` |`30000` |The max client side poll timeout in milliseconds. A client will be
removed if a connection is not received in this time.

|`multiFrameInterval` |`1500` |The client side poll timeout, if multiple connections are detected from
the same browser.

|`jsonCommented` |`true` |If `true`, the server will accept JSON wrapped in a comment and will
generate JSON wrapped in a comment. This is a defence against Ajax
Hijacking.

|`logLevel` |`1` |`0`=none, `1`=info, `2`=debug.

|`crossOriginFilterOn` |`false` |*Camel 2.10:* If `true`, the server will support for cross-domain
filtering

|`allowedOrigins` |`*` |*Camel 2.10:* The origins domain that support to cross, if the
`crosssOriginFilterOn` is `true`

|`filterPath` |  | *Camel 2.10:* The filterPath will be used by the CrossOriginFilter, if
the `crosssOriginFilterOn` is `true`

|`disconnectLocalSession` |  | *Camel 2.10.5/2.11.1: (Producer only)*: Whether to disconnect local
sessions after publishing a message to its channel. Disconnecting local
session is needed as they are not swept by default by CometD, and
therefore you can run out of memory. In Camel 2.16.1/2.15.5 or older the
default value is true. From newer versions the default value is false.
|=======================================================================

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

Here is some examples on How to pass the parameters

For file (for webapp resources located in the Web Application directory
--> cometd://localhost:8080?resourceBase=file./webapp +
 For classpath (when by example the web resources are packaged inside
the webapp folder -->
cometd://localhost:8080?resourceBase=classpath:webapp

[[Cometd-Authentication]]
Authentication
^^^^^^^^^^^^^^

*Available as of Camel 2.8*

You can configure custom `SecurityPolicy` and `Extension`'s to the
`CometdComponent` which allows you to use authentication as
http://cometd.org/documentation/howtos/authentication[documented here]

[[Cometd-SettingupSSLforCometdComponent]]
Setting up SSL for Cometd Component
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

[[Cometd-UsingtheJSSEConfigurationUtility]]
Using the JSSE Configuration Utility
++++++++++++++++++++++++++++++++++++

As of Camel 2.9, the Cometd 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 Cometd component. You need to configure SSL
on the CometdComponent.

[[Cometd-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");

TrustManagersParameters tmp = new TrustManagersParameters();
tmp.setKeyStore(ksp);

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

CometdComponent commetdComponent = getContext().getComponent("cometds", CometdComponent.class);
commetdComponent.setSslContextParameters(scp);
-----------------------------------------------------------------------------------------------

[[Cometd-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:trustManagers>
      <camel:keyStore
          resource="/users/home/server/keystore.jks"
          password="keystorePassword"/>
    </camel:keyManagers>
  </camel:sslContextParameters>...
 
  <bean id="cometd" class="org.apache.camel.component.cometd.CometdComponent">
    <property name="sslContextParameters" ref="sslContextParameters"/>
  </bean>
...
  <to uri="cometds://127.0.0.1:443/service/test?baseResource=file:./target/test-classes/webapp&timeout=240000&interval=0&maxInterval=30000&multiFrameInterval=1500&jsonCommented=true&logLevel=2"/>...
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

[[Cometd-SeeAlso]]
See Also
^^^^^^^^

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

