Yes, I'm calling WDialog::exec() from within a posted event. However, the exception is caused by calling WDialog::exec() and then having the session timeout. It does not seem to be dependent on being called from WServer::post().
I can reproduce the problem by running examples/dialog/dialog.wt, and clicking the 'Familiar' button, which shows a dialog using WDialog::exec(). Once the "Personalia" dialog is displayed, leave the dialog showing, close the window/tab, and wait for the timeout. [2012-Nov-19 08:50:46.369030] 22859 [/ 9sEovbI28uHH14WN] [info] "WebController: timeout: expiring" [2012-Nov-19 08:50:46.369859] 22859 [/ 9sEovbI28uHH14WN] [error] "Wt: error during event handling: doRecursiveEventLoop(): session was killed" [2012-Nov-19 08:50:46.370085] 22859 [/ 9sEovbI28uHH14WN] [error] "Wt: fatal error: doRecursiveEventLoop(): session was killed" On Nov 19, 2012, at 1:46 AM, Koen Deforche <k...@emweb.be> wrote: > Hey Boris, > > I believe you're right, there seems to be some incompatibility with > post() and recursive event loops. > > Joseph, I'm correct that you are calling WDialog::exec() from within a > posted event ? > I would like to reproduce this behaviour in a small test case. > > Regards, > koen > > 2012/11/17 Nagaev Boris <bnag...@gmail.com>: >> Hello! >> >> You are still using recursive event loop. Try not to use recursive >> event loop with WServer::post(). Use WDialog->show() instead of >> WDialog::exec(). Make sure to remove this WDialog, when it is closed. >> >> On Sat, Nov 17, 2012 at 4:13 AM, Joseph VanAndel <vanan...@ucar.edu> wrote: >>> OK, I've modified my application to use wApp->bind() as shown below. >>> >>> Unfortunately, if a session dies, my application still crashes, as before: >>> ================== >>> terminate called after throwing an instance of 'Wt::WException' >>> what(): doRecursiveEventLoop(): session was killed >>> >>> #5 0x00b3a183 in std::terminate() () from /usr/lib/libstdc++.so.6 >>> #6 0x00b3a2c2 in __cxa_throw () from /usr/lib/libstdc++.so.6 >>> #7 0x01767af8 in Wt::WebSession::doRecursiveEventLoop ( >>> this=0xb5e3f850) >>> at /usr/local/src/wt-3.2.3/src/web/WebSession.C:1051 >>> #8 0x0143a7da in Wt::WDialog::exec (this=0x87fedb8, >>> animation=...) at /usr/local/src/wt-3.2.3/src/Wt/WDialog.C:292 >>> #9 0x08125562 in Login_GUI::confirm (this=0x87fed48, >>> message=..., info=..., id=..., passwd=..., name=..., >>> location=..., comment=...) at src/view/Login_GUI.cpp:75 >>> #10 0x0816e002 in UIServer::showLogin (this=0x876aeb8, >>> message=..., info=...) at src/view/UIServer.cpp:716 >>> #11 0x0816f107 in UIServer::processStatusEvent (this=0x876aeb8, >>> event=...) at src/view/UIServer.cpp:920 >>> #12 0x0816f01c in UIServer::notifyStatusEvent (this=0x876aeb8) >>> at src/view/UIServer.cpp:913 >>> #13 0x08150537 in boost::_mfi::mf0<void, UIServer>::operator() ( >>> this=0x87fed10, p=0x876aeb8) >>> ====================== >>> Although the session was killed, the WServer::post() call still invokes the >>> callback, which eventually tries to post a WDialog. >>> Wt::WebSession::doRecursiveEventLoop sees the session is dead, and throws >>> an error. >>> >>> What I don't understand is how this could happen. WServer::post() >>> schedules a call to >>> WebController::handleApplicationEvent(), which checks whether the session >>> corresponding to sessionID is alive before it invokes the session's >>> callback. >>> >>> >>> On Nov 13, 2012, at 9:30 AM, Joseph VanAndel <vanan...@ucar.edu> wrote: >>> >>>> Yes, although the logic is more complex, I can have the bound function >>>> callback into the shared object to retrieve the data that I wanted to pass >>>> to the bound function. >>>> >>>> For my application, I have a UIServer object (1 per session) and a >>>> StatusServer (singleton), which relays status messages between sessions. >>>> UIServer ctor calls >>>> StatusServer::connect( this, >>>> wApp->bind( boost::bind( &UIServer::notifyStatusEvent, this) )) >>>> >>>> StatusServer::postStatusEvent() will save a copy of the event in a >>>> per-session queue. >>>> and calls WServer::post(sessionid, callback), which indirectly calls >>>> UIServer::notifyStatusEvent() >>>> >>>> UIServer::notifyStatusEvent() calls >>>> StatusServer::getEvent() to retrieve the event, and call >>>> UIServer::processStatusEvent() to handle the StatusEvent. >>>> >>>> >>>> It would be quite helpful if <Wt_src>/examples/simplechat used >>>> WApplication::bind(). >>>> >>>> I appreciate any examples, but examples that correctly handle real-world >>>> situations, like browser sessions being closed are MUCH more useful. As >>>> far as I can tell, because simplechat doesn't use WApplication::bind(), it >>>> may not safely handle browser sessions that are closed. >>>> >>>> If I get the chance, I'll submit a rewritten simplechat example that uses >>>> WApplication::bind(), but as they say "It won't be pretty!" >>>> >>>> >>>> On Nov 13, 2012, at 4:44 AM, Koen Deforche wrote: >>>> >>>>> Hey Joseph, Rob, >>>>> >>>>> I guess you are both indicating a limitation: WApplication::bind() >>>>> essentially returns a function without arguments, and thus all >>>>> arguments already have to be bound before the call, which makes it >>>>> useless when you want to pass on information from the external source. >>>>> >>>>> As a workaround, perhaps you can rather than 'push' new information, >>>>> make the bound function 'poll' the information from the shared object >>>>> ? >>>>> >>>>> I believe it should be possible to make WApplication::bind() work >>>>> properly with any kind of function, including functions with free >>>>> parameters -- although that requires a bit of digging into the >>>>> meta-function possiblities of boost-ified c++... >>>>> >>>>> In any case, using WApplication::bind() later on is not very useful -- >>>>> it needs to happen with the session lock and with the objects bound >>>>> guaranteed to be alive at the moment of calling WApplication::bind(). >>>>> >>>>> Regards, >>>>> koen >>>>> >>>>> ------------------------------------------------------------------------------ >>>>> Monitor your physical, virtual and cloud infrastructure from a single >>>>> web console. 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Get in-depth insight into apps, servers, databases, vmware, >> SAP, cloud infrastructure, etc. Download 30-day Free Trial. >> Pricing starts from $795 for 25 servers or applications! >> http://p.sf.net/sfu/zoho_dev2dev_nov >> _______________________________________________ >> witty-interest mailing list >> witty-interest@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/witty-interest > > ------------------------------------------------------------------------------ > Monitor your physical, virtual and cloud infrastructure from a single > web console. Get in-depth insight into apps, servers, databases, vmware, > SAP, cloud infrastructure, etc. Download 30-day Free Trial. > Pricing starts from $795 for 25 servers or applications! > http://p.sf.net/sfu/zoho_dev2dev_nov > _______________________________________________ > witty-interest mailing list > witty-interest@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/witty-interest ------------------------------------------------------------------------------ Monitor your physical, virtual and cloud infrastructure from a single web console. Get in-depth insight into apps, servers, databases, vmware, SAP, cloud infrastructure, etc. Download 30-day Free Trial. Pricing starts from $795 for 25 servers or applications! http://p.sf.net/sfu/zoho_dev2dev_nov _______________________________________________ witty-interest mailing list witty-interest@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/witty-interest
