WebSocket Event Receiver

WebSocket event receiver is an internal event receiver that comes with WSO2 products by default. You can configure it with XML, JSON, and text input mapping types.

The websocket event receiver should be used when the event source is a websocket server to which the CEP server need to connect in order to receive events. However, if the event source is a websocket client, the event source should connect to the inbuilt web socket server of WSO2 CEP. In such scenarios, use the WebSocket Local Event Receiver.

Prerequisites

Start the WebSocket server, before starting the event receiver configurations.

Creating a WebSocket event receiver

For instructions on creating a WebSocket event receiver, see Configuring Event Receivers.

Configuring adapter properties

Specify the Adapter Properties , when creating a WebSocket event receiver using the management console as shown below.

After entering the above adapter properties, select the Event Stream to which you want to map the incoming events, and the Message Format that you want to apply on the receiving events. Also, click Advanced to define custom input mappings based on the Message Format you selected. For more information on custom input mapping types, see Input Mapping Types.

You can also d efine the respective adapter properties of the event receiver based on the transport type within the <from> element of the event receiver configuration in the <PRODUCT_HOME>/repository/deployment/server/eventreceivers/ directory as follows.

<eventReceiver name="WebsocketInputEventAdapter" statistics="disable" trace="disable" xmlns="http://wso2.org/carbon/eventreceiver">
    <from eventAdapterType="websocket">
        <property name="websocket.server.url">ws://localhost:9099</property>
        <property name="events.duplicated.in.cluster">false</property>
    </from>
    ...................
</eventReceiver>

The above adapter properties are described below.

Adapter Property	Description	Configuration file property	Example
Web Socket Server URL	URL of the WebSocket server to which you want to connect to	websocket.server.url	`ws://localhost:9099`
Is events duplicated in cluster	In a cluster whether the same event can reach two receiver nodes	events.duplicated.in.cluster	`true/false`

Related samples

For more information on websocket event receiver type, see the following sample.

Sample 0019 - Receiving JSON Events via WebSocket Transport