Websocket Component

Available as of Camel 2.10

The websocket component provides websocket endpoints for communicating with clients using websocket. The component uses Eclipse Jetty Server which implements the IETF specification (drafts and RFC 6455). It supports the protocols ws:// and wss://. To use wss:// protocol, the SSLContextParameters must be defined.

Version currently supported
As Camel 2.10 uses Jetty 7.5.4.v20111024, only the D00 to D13 IETF implementations are available.

URI format

websocket://hostname[:port][/resourceUri][?options]

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

Options

Name	Default Value	Description
sslContextParameters		Reference to a `org.apache.camel.util.jsse.SSLContextParameters` in the Registry. This reference overrides any configured SSLContextParameters at the component level. See Using the JSSE Configuration Utility.

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

To use ssl and websocket secure --> websocket://localhost:8443?/test?sslContextParametersRef=#sslContextParameters

Message Headers

The websocket component uses 2 headers to indicate to either send messages back to a single/current client, or to all clients.

Key	Description
`WebsocketConstants.SEND_TO_ALL`	Sends the message to all clients which are currently connected. You can use the `sendToAll` option on the endpoint instead of using this header.
`WebsocketConstants.CONNECTION_KEY`	Sends the message to the client with the given connection key.

Component Options

The WebsocketComponent must be configured prior to use, to setup host, to act as a websocket server.

Option	Default	Description
Host	0.0.0.0	The hostname.
Port	9292	The port number.
StaticResources	`null`	Path for static resources such as index.html files etc.

Endpoint Options

The WebsocketEndpoint can be configured prior to use

Option	Default	Description
sendToAll	`null`	To send to all websocket subscribers. Can be used to configure on endpoint level, instead of having to use the `WebsocketConstants.SEND_TO_ALL` header on the message.

Usage

In this example we let Camel exposes a websocket server which clients can communicate with. The websocket server uses the default host and port, which would be 0.0.0.0:9292.
The example will send back an echo of the input. To send back a message, we need to send the transformed message to the same endpoint "websocket://echo". This is needed
because by default the messaging is InOnly.

// expose a echo websocket client, that sends back an echo
from("websocket://echo")
    .log(">>> Message received from WebSocket Client : ${body}")
    .transform().simple("${body}${body}")
    // send back to the client, by sending the message to the same endpoint
    // this is needed as by default messages is InOnly
    // and we will by default send back to the current client using the provided connection key
    .to("websocket://echo");

This example is part of an unit test, which you can find here. As a client we use the AHC library which offers support for web socket as well.

[CONF] Apache Camel > Websocket

Websocket

Page edited by charles Moulliard

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