Hi, On Mon, Jan 22, 2024 at 6:09 PM Martin Simons <martin@simulogics.games> wrote:
> Hey everyone, > > I started a gnarly migration of a really old Wicket 6 application to > Wicket 9 last week. One of the objectives was to move away from a > .war-based deployment to a Tomcat app server, and instead go with an > embedded server which runs within a Docker file. The choice here fell on > Jetty 12 using the EE8 environment. > Are you still able to deploy to Tomcat ? If YES then it would be good to check whether your app will experience the same errors there too! > > So far, so good. After getting all the API changes sorted out, most things > work as expected. But what puzzles me is that I get the logs flooded with > exceptions because different pieces of code try to write to the web > response at a point in the web request cycle when it has already been > committed. > > For Wicket itself, this affects the COOP and COEP filters when handling > HEAD requests. > COOP and COEP are new in Wicket 9.x, so it is quite possible that they might have issues with HEAD requests. Please provide failing unit tests and/or a quickstart and/or at least stacktraces! > > My one code is affected (for example) when trying to set a cookie at the > end of a request cycle. > > So two questions: > > 1. I am likely missing something obvious. Does anyone see what it might > be? > 2. Regarding my own code: I get that I can’t write to a response that’s > been committed, but what’s “the Wicket way” to modify a response header > after the response has been processed but before it is written? > RequestCycleListener::onEndRequest() seems to be too late. RequestCycle[Listener]#onEndRequest() is called before HttpServletResponse#flush(), so it shouldn't be that late. But I need to debug the app to tell whether the response is buffering or not. See org.apache.wicket.protocol.http.HeaderBufferingWebResponse If you were using Wicket 10.x + servlet-api 6.x then you could use https://jakarta.ee/specifications/servlet/6.0/apidocs/jakarta.servlet/jakarta/servlet/http/httpservletresponse#setTrailerFields(java.util.function.Supplier) > > I found surprisingly little on this problem when googling, so I am almost > certain it’s my mistake. But after looking at it for days, I am sort of > stuck. I would greatly appreciate a few pointers. > > Thank you very much, > Martin >
