WebSocket not working on Jetty 9.4

Question

My websocket servlet does not work on Jetty 9.4.6.v20170531 although it works perfectly with version 9.3.2.v20150730.

My code looks like this:

@SuppressWarnings("serial")
@WebServlet(name = "TcpProxy", urlPatterns = { "/sockets/tcpProxy" })
public class TcpProxySocketServlet extends WebSocketServlet {

    @Override
    public void configure(WebSocketServletFactory factory) {
        factory.register(TcpProxySocket.class);
    }
}

and

@WebSocket
public class TcpProxySocket {

    /* ... */

    public TcpProxySocket() {
        LOGGER.info("Instantiating a TCP proxy");
    }


    /**
     * Open a new socket
     *
     * @param session the session
     */
    @OnWebSocketConnect
    public void onConnect(Session session) throws RestException {
        this.session = session;
        CachedSession toriiSession = null;
    ...

When trying to access my socket, I get a 404 error. On server side, the configure is never called.

I tried to force the loading of the servlet by adding it to web.xml

<servlet>
    <servlet-name>TcpProxySocket</servlet-name>
    <servlet-class>com.fujitsu.fse.torii.servlets.tcpProxy.TcpProxySocketServlet</servlet-class>
</servlet>
<servlet-mapping>        <servlet-name>TcpProxySocket</servlet-name>
    <url-pattern>/sockets/tcpProxy</url-pattern>
</servlet-mapping>

Then the servet is loaded, configure function is called. When trying to open the socket, I don't get any error but the onConnect error is never called.

So far I have reverted to using Jetty 9.3.2, but it's not satisfying.

Any Idea ?

Answer 1

This was fixed by using a correct web-app markup in web.xml to use webapp version 3.1

@@ -1,6 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
+<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
+         version="3.1">

The other problem was that the onConnect method was never called. It disappeared when I changed the servlet mapping using a path with a trailing slash ("/sockets/scripts/" instead of "/sockets/scripts").

We could not reproduce the trailing-slash problem on a simpler example. So I'm not sure if there was an actual problem or if it was just a misinterpretation of mine.

the full story is on https://github.com/eclipse/jetty.project/issues/1800 I thank Joakim and the Jetty project for their reactivity.

Answer 2

I had the same issue with Java Spark web framework when they updated Jetty to 9.4. The trailing slash issue mentioned by Michael Dussere did the trick for me, I changed the path in my client from "http://example.org/chat/" to "http://example.org//chat" (in the server it is ".../chat" as well).