Fire event without impacting ZK session timeout - session-timeout

Question

I'm having trouble getting the ZK session timeout to occur because our application polls the server every few minutes for information. The code that triggers this polling is Javascript which clicks a hidden button, sending an onClick event to the server.
Do you know of any way to tell ZK that this polling is automated and should not affect the session timeout timer?
Thanks very much.
-Ian

Answer 1

A workaround is write a filter to detect whether a request is that poll request and log the time of 'real' request in filter then invalidate session if no real request for a long time.
sample:
test.zul
<zk>
<intbox id="ibx" value="1" />
<timer delay="1000" id="pooltimer" repeats="true">
<attribute name="onTimer"><![CDATA[
ibx.setValue(ibx.getValue() + 1);
]]></attribute>
</timer>
<button label="click or invalidated in 20 seconds">
<attribute name="onClick"><![CDATA[
long lastRealRequest = (Long)Sessions.getCurrent().getAttribute("LAST_REAL_REQUEST");
alert("only pooling request in "
+ ((System.currentTimeMillis() - lastRealRequest) / 1000)
+ " second(s)");
]]></attribute>
</button>
</zk>
zk.xml
<zk>
<session-config>
<session-timeout>20</session-timeout>
</session-config>
</zk>
filter in web.xml
<filter>
<filter-name>requestFilter</filter-name>
<filter-class>test.RequestFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>requestFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
RequestFilter.java
package test;
import java.io.IOException;
import java.util.Map;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
public class RequestFilter implements Filter {
public void init(FilterConfig filterConfig) throws ServletException {
}
#Override
public void doFilter(ServletRequest request, ServletResponse response,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest)request;
Map param = req.getParameterMap();
HttpSession sess = req.getSession();
boolean isRealRequest = true;
// here detect whether it is the poll request
// initiate the LAST_REAL_REQUEST if the poll request is
// the first request
//
// invalidate session if no real request within session timeout range
for (Object key : param.keySet()) {
if (key.toString().startsWith("cmd")
&& "onTimer".equals(((String[])param.get(key))[0])) {
// not real request
isRealRequest = false;
// try get last real request time
Long lastRealRequest = (Long)sess.getAttribute("LAST_REAL_REQUEST");
if (lastRealRequest == null) {
System.out.println("init");
// init if no previous real request
lastRealRequest = System.currentTimeMillis();
sess.setAttribute("LAST_REAL_REQUEST", lastRealRequest);
} else if ((System.currentTimeMillis() - lastRealRequest) > 20000) {
System.out.println("invalidate");
// invalidate session if only poll request for a long time
sess.invalidate();
}
}
}
// process request
chain.doFilter(request, response);
// update LAST_REAL_REQUEST if this is a real request
if (isRealRequest) {
// record last real request time
sess.setAttribute("LAST_REAL_REQUEST", System.currentTimeMillis());
}
}
#Override
public void destroy() {}
}

Answer 2

Short answer is NO.
Long answer is, first of all there is no "ZK Session". It is just HttpSession as defined by Servlet specification. Second, session management is done by servlet web container so the session timeout counter reset is done long before the request is passed to ZK for handling.