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Cometd Component

The cometd: component is a transport for working with the jetty implementation of the 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:

URI format

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

Examples

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

where cometds: represents an SSL configured endpoint.

Options

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

true

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.

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

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 documented here

Setting up SSL for Cometd Component

Using the JSSE Configuration Utility

As of Camel 2.9, the Cometd component supports SSL/TLS configuration through the 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.

Programmatic configuration of the component
Spring DSL based configuration of endpoint

See Also

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3 Comments

  1. In options : resourceBase is not reconized in the new version it renamed "baseResource".
    (I work with camel 2.7.1 and resourceBase doesn't work, you need to use "baseResource")

  2. The URL with the blog entry seems to be dead.
    "See this blog entry by David Greco who contributed this component to Apache Camel, for a full sample"
    the url: "http://www.davidgreco.it/MySite/Blog/Entries/2008/12/4_Camel,_Cometd_and_Bayeux_what_a_nice_combination.html"
    Any idea where I can find the example in question?