Attach a Ballerina WebSocket service to a http:Listener.

websocket_service_attach.bal

import ballerina/http;
import ballerina/io;

listener http:Listener ep = new (9090);
service wsService = @http:WebSocketServiceConfig {} service {
    resource function onText(http:WebSocketCaller wsEp, string text) {
        io:println("Sever Received: " + text);
    }
    resource function onClose(http:WebSocketCaller wsEp, int statusCode, string reason) {
        io:println("Connection closed");
    }
};
public function main() {
    var err = ep.__attach(wsService);
    if (err is error) {
        io:println("error in attaching service to Listener", err);
    }
}

Call the service as var ws = new WebSocket("ws://localhost:9090"); using a js client