Re: [undertow-dev] response-code handler bypasses configured error pages

Stuart, any further suggestions or answers to my outstanding questions? So far, everything you've suggested doesn't work for various reasons I've shared here. I also have a number of outstanding questions such as how I could access the deployment information for the servlet's error pages from inside an HTTPHandler running in the initial handler chain that fires in the XNIO worker. Thanks! ~Brad *Developer Advocate* *Ortus Solutions, Corp * E-mail: brad(a)coldbox.org ColdBox Platform: http://www.coldbox.org Blog: http://www.codersrevolution.com On Fri, Jul 3, 2020 at 3:55 PM Brad Wood <bdw429s(a)gmail.com&gt; wrote: > After a few hours of experimenting, I was able to answer a few of my own > questions, but not all of them. > > - Yes, it is possible to contribute a custom handler to the predicate > language-- this is actually pretty sweet. I didn't realize just how > generic the parser was. > - In order to get "picked up", the builder class must be listed in > the > *META-INF/services/io.undertow.server.handlers.builder.HandlerBuilder* > file > - That custom handler suggested by Stuart in the previous message > ONLY works if the predicate chain is wrapped "inside" the servlet initial > handler. Otherwise, the servletcontext classes are missing. This > unfortunately, makes it a no-go for me to be able to use. > > The rest of my questions still stand however in so far as how I can > accomplish what I need. > > During my experiments today, I also played with the error-file handler, > but it also is of no use. Since the response-code handler ends the > exchange, any error pages declared in the error file handler are never > used! > > error-file( response-codes={404}, > file="C:\sandbox\predicatetest\custom404.html" ) > path('/box.json') -> response-code(404) > > I even tried creating a custom handler that sets the status code but > continues the exchange, but then that just serves the original file anyway, > which causes the error-file handler to do nothing since the response stream > is already started. > > Thanks! > > ~Brad > > *Developer Advocate* > *Ortus Solutions, Corp * > > E-mail: brad(a)coldbox.org > ColdBox Platform: http://www.coldbox.org > Blog: http://www.codersrevolution.com > > > > On Fri, Jul 3, 2020 at 12:02 PM Brad Wood <bdw429s(a)gmail.com&gt; wrote: > >> You probably need to write a custom one that looks like this (plus the >>> relevant predicate languge bits): >> >> >> Stuart, if I can branch the conversation here back to your idea of a >> custom handler for a bit... >> >> I'm still toying with this, and while the handleRequest() code you have >> makes perfect sense, I think I'm missing a lot of context on how you were >> suggesting this would work. >> >> - The code you put in your message-- were you suggesting that should >> be added to the Undertow core as a built in handler or just a custom class >> I would put in my project? >> - Would this handler require the predicates be processed downstream >> of the servlet initial handler in order to work? Because if so, that >> appears to be a no-go since handlers like the rewrite only appear to work >> upstream of the servlet >> - Is it possible to register custom handlers of my own creation with >> the predicate language or were you suggesting a handler that could only be >> manually configured? I'm familiar with the handler builder pattern that >> the built in handlers use, but I'm unclear on how builders get registered >> with the predicate handler parser. >> - Actually, I just reviewed the code again now and I see >> the loadHandlerBuilders() method in the PredicatedhandlersParser class >> appears to be scanning the classpath for builders. Interesting.... Does >> Undertow need to be loaded by the same class loader that loaded my custom >> handlers for this to work? I'm not super familiar with the ServiceLoader >> stuff >> - I'm not against building a custom handler that I ship alongside >> Undertow that provides what I'm looking for, but I'm still interested in >> having the conversation of how we can improve undertow's core offering. >> >> Thanks! >> >> ~Brad >> >> *Developer Advocate* >> *Ortus Solutions, Corp * >> >> E-mail: brad(a)coldbox.org >> ColdBox Platform: http://www.coldbox.org >> Blog: http://www.codersrevolution.com >> >> >> >> On Thu, Jul 2, 2020 at 7:01 PM Stuart Douglas <sdouglas(a)redhat.com&gt; >> wrote: >> >>> Hmm, this is because the servlet status code is only triggered by a >>> sendError method, not by just setting the code. >>> >>> You probably need to write a custom one that looks like this (plus the >>> relevant predicate languge bits): >>> >>> public class SendErrorHandler implements HttpHandler { >>> >>> private final int code; >>> >>> public SendErrorHandler(int code) { >>> this.code = code; >>> } >>> >>> @Override >>> public void handleRequest(HttpServerExchange exchange) throws >>> Exception { >>> ServletRequestContext src = >>> exchange.getAttachment(ServletRequestContext.ATTACHMENT_KEY); >>> ((HttpServletResponse)src.getServletResponse()).sendError(code); >>> } >>> } >>> >>> Stuart >>> >>> >>> >>> On Fri, 3 Jul 2020 at 09:40, Brad Wood <bdw429s(a)gmail.com&gt; wrote: >>> >>>> Thanks for the reply Stuart. I've tried this with no success, but >>>> perhaps I'm doing it wrong. >>>> >>>> List<PredicatedHandler> ph = >>>> PredicatedHandlersParser.parse(predicatesLines, _classLoader); >>>> servletBuilder.addOuterHandlerChainWrapper(next -> >>>> Handlers.predicates(ph,next)); >>>> >>>> When the response-code handler fires, I still get no response body. >>>> >>>> On a related note, when I move the predicates into an outer handler >>>> chain wrapper, my default response listener also doesn't fire at all. >>>> >>>> On an unrelated train of thought, I've been trying to see if I can get >>>> the default response listener to automatically dispatch the correct error >>>> page, but that hasn't been going well either. If I don't use the outer >>>> handler chain idea, but try to capture the empty response in a default >>>> response listener, I can return a static message using the Sender class >>>> >>>> Sender sender = exchange.getResponseSender(); >>>> sender.send(errorHTMLString); >>>> >>>> But if I try to run something this in my default response listener to >>>> invoke my error pages >>>> >>>> ServletRequestContext src = >>>> exchange.getAttachment(ServletRequestContext.ATTACHMENT_KEY); >>>> HttpServletResponseImpl response = src.getOriginalResponse(); >>>> response.doErrorDispatch( exchange.getStatusCode(), >>>> exchange.getReasonPhrase() ); >>>> >>>> Then it's as though nothing happens and I still get an empty response. >>>> >>>> Thanks! >>>> >>>> ~Brad >>>> >>>> *Developer Advocate* >>>> *Ortus Solutions, Corp * >>>> >>>> E-mail: brad(a)coldbox.org >>>> ColdBox Platform: http://www.coldbox.org >>>> Blog: http://www.codersrevolution.com >>>> >>>> >>>> >>>> On Thu, Jul 2, 2020 at 6:17 PM Stuart Douglas <sdouglas(a)redhat.com&gt; >>>> wrote: >>>> >>>>> The predicate languages are executed before the Servler handlers, so >>>>> they won't be handled by Servlet error pages. >>>>> >>>>> If you are setting this all up programmatically you could use >>>>> io.undertow.servlet.api.DeploymentInfo#addOuterHandlerChainWrapper to setup >>>>> the predicate handler after the initial servlet one, which should mean that >>>>> the servlet error handling will handle the response code. >>>>> >>>>> Stuart >>>>> >>>>> On Fri, 3 Jul 2020 at 08:25, Brad Wood <bdw429s(a)gmail.com&gt; wrote: >>>>> >>>>>> When I configure an error page similar to this: >>>>>> >>>>>> servletBuilder.addErrorPage( new ErrorPage( "404.html", 404)); >>>>>> >>>>>> This works great when I hit a path in my browser that doesn't >>>>>> exist. The contents of the *404.html* file is served with a >>>>>> response code of *404*. >>>>>> >>>>>> However, if I also use the predicate language to define something >>>>>> like: >>>>>> >>>>>> path(/box.json)->response-code(404) >>>>>> >>>>>> and then I hit *localhost/box.json* in my browser, I get a *404* >>>>>> status code but with no response body. >>>>>> >>>>>> - The docs say the response-code handler ends the exchange, but >>>>>> should it still respect the error pages? >>>>>> - How can I modify my use of Undertow to respect the error pages >>>>>> when using the response-code handler? >>>>>> - I've seen in the docs the ability to have a >>>>>> *addDefaultResponseListener()* but I'm not sure if it is the >>>>>> correct solution for this, nor how I would access the error page >>>>>> configuration dynamically as to not need to duplicate my work. >>>>>> >>>>>> Thanks! >>>>>> >>>>>> ~Brad >>>>>> >>>>>> *Developer Advocate* >>>>>> *Ortus Solutions, Corp * >>>>>> >>>>>> E-mail: brad(a)coldbox.org >>>>>> ColdBox Platform: http://www.coldbox.org >>>>>> Blog: http://www.codersrevolution.com >>>>>> >>>>>> _______________________________________________ >>>>>> undertow-dev mailing list >>>>>> undertow-dev(a)lists.jboss.org >>>>>> https://lists.jboss.org/mailman/listinfo/undertow-dev >>>>> >>>>>