[wildfly-dev] WF 8.0 HTTP Upgrade help needed

[Przemyslaw Bielicki]

I tried - exactly the same results.

Another weird observation is that ServletOutputStream.isReady() is
returning true even after the connection is closed
(ServletInputStream.isFinished() is correctly returning true).

Here's the scenario that works but I can write back the data only once:
1. In HttpUpgradeHandler I set only  the ReadListener
2. I switch the protocol and send some data
3. ReadListener gets activated i.e. onDataAvailable() is called.
4. I process the input data, read as much as possible and put the input
into the queue
5. From within ReadListener I set the WriteListener
6. WriteListener.onWritePossible() gets called and I process the data - I
clean the queue
7. As long as I'm in WriteListener.onWritePossible() (while.out.isReady()
is constantly returning true, which is a correct bahavior) the ReadListener
is on-hold. I can send as much data as I like but onDataAvailable() is not
called
8. Only when I leave WriteListener.onWritePossible() method the
ReadListener.onDataAvailable() is called again and I can consume the input
data again.
9. I can process the input data again i.e. put it into the queue but
WriteListener.onWritePossible() is never called again. When I try to reset
it I get IllegalStateException

Either the specification or implementation seem not very mature.... Wildfly
behavior is consistent with the one of Tomcat.

At the moment I conclude that the non-blocking write is not possible in
Servlet 3.1.

I would appreciate if someone can provide an example that actually works or
explain why the weird behavior I observe is correct (is it?)

Cheers,
Przemyslaw




On Thu, Apr 3, 2014 at 6:18 AM, Stuart Douglas
<stuart.w.douglas at gmail.com>wrote:

> Can you try with the latest development build of Wildfly (from
> https://ci.jboss.org/hudson/job/WildFly-latest-master/).
>
> There have been some fixes in this area, so your problem may have already
> been fixed.
>
> Stuart
>
>
> PB wrote:
>
>> Hi,
>>
>> I'm testing the HTTP Upgrade feature of WF 8.0 and I'm facing some banal
>> problem. Basically my ReadListener is NEVER called.
>> Here's the code:
>>
>> @WebServlet(urlPatterns = "/upgrade")
>> public class UpgradeServlet extends HttpServlet {
>>    @Override
>>    protected void doGet(HttpServletRequest req, HttpServletResponse
>> resp) throws ServletException, IOException {
>>      if ("upgrade".equalsIgnoreCase(req.getHeader("Connection"))) {
>>        req.upgrade(EchoHandler.class);
>>      }
>>    }
>> }
>>
>> public class EchoHandler implements HttpUpgradeHandler {
>>    @Override
>>    public void init(WebConnection wc) {
>>      try {
>>        ServletInputStream in = wc.getInputStream();
>>        ServletOutputStream out = wc.getOutputStream();
>>
>>        BlockingQueue<String> queue = new LinkedBlockingQueue<String>();
>>        in.setReadListener(new EchoReadListener(queue, in));
>>        out.setWriteListener(new EchoWriteListener(queue, out));
>>      } catch (IOException e) {
>>        throw new IllegalStateException(e);
>>      }
>>    }
>>
>> public class EchoReadListener implements ReadListener {
>>    @Override
>>    public void onDataAvailable() throws IOException {
>>      while (in.isReady()) {
>>        int length = in.read(buffer);
>>        String input = new String(buffer, 0, length);
>>        if (false == queue.offer(input)) {
>>          System.err.println("'" + input + "' input was ignored");
>>        }
>>      }
>>    }
>>
>> I'm connecting to WF using telnet and sending the upgrade request:
>> GET /example-webapp/upgrade HTTP/1.1
>> Host: localhost
>> Connection: upgrade
>> Upgrade: echo
>>
>> and I'm getting correct response:
>>
>> HTTP/1.1 101 Switching Protocols
>> Connection: Upgrade
>> X-Powered-By: Undertow 1
>> Server: Wildfly 8
>> Content-Length: 0
>>
>> which means that from now on the protocol between my telnet client and
>> WF is pure TCP.
>> So, I start typing some text, hit Enter and.... nothing happens.
>> onDataAvailable() is NEVER called. More so, this makes WF totally
>> irresponsive - my whole webapp is dead.
>>
>> I believe, I'm doing something wrong - any ideas what exactly? There is
>> also a slight chance that Upgrade feature in WF is f****d :)
>> Anyway, WF should not block even in case my upgraded protocol is not
>> working correctly?
>>
>> Many thanks,
>> Przemyslaw
>>
>> _______________________________________________
>> wildfly-dev mailing list
>> wildfly-dev at lists.jboss.org
>> https://lists.jboss.org/mailman/listinfo/wildfly-dev
>>
>
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