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

Forgot to reply to this: add a 'continue' param to the response code handler, I'm not against adding this, however I would be unlikely to use responseCode( value=404, continue=true ) as I'd want to have a cleaner predicate language. I'd rather a new handler be introduced like the custom send-error-page( 404 ) one I've been testing with that is readable and clear what it does. 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 Tue, Jul 7, 2020 at 8:51 PM Brad Wood <bdw429s(a)gmail.com&gt; wrote: > Genius idea. In all my tests I hadn't thought of setting the response > code in the predicate and then letting it continue to the servlet and > caching it there. I just tested this and it does appear to work well. > > I added this outer handler chain wrapper to my deployment info > > deploymentInfo.addOuterHandlerChainWrapper(next -> new > HttpHandler() { > @Override > public void handleRequest(HttpServerExchange exchange) throws > Exception { > if( exchange.getStatusCode() > 399 && > exchange.getResponseContentLength() == -1 ) { > ServletRequestContext src = > exchange.getAttachment(ServletRequestContext.ATTACHMENT_KEY); > > ((HttpServletResponse)src.getServletResponse()).sendError(exchange.getStatusCode()); > } else { > next.handleRequest(exchange); > } > } > }); > > (I don't know if the exchange.getResponseContentLength() check is needed > or the best way to do that) > > And then I registered a custom handler I called *send-error-page* that > has this handleRequest method: > > public void handleRequest(final HttpServerExchange exchange) throws > Exception { > exchange.setStatusCode(responseCode); > next.handleRequest(exchange); > } > > Then this predicate rule > > path(/box.json)->send-error-page(404) > > serves up my servlet's custom error page for that request. > > 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 Tue, Jul 7, 2020 at 6:39 PM Stuart Douglas <sdouglas(a)redhat.com&gt; > wrote: > >> Basically I think the only way you can solve this is to attach the error >> code to the exchange somehow, then have a handler that reads the error code >> and calls sendError later.Basically write a new response-code handler that >> sets the code then calls the next handler (so the request gets to Servlet), >> then add a handler to the Servlet deployment that calls sendError if the >> exchange status code is > 400. >> >> We could actually add this to Undertow very simply, just add a >> 'continue' param to the response code handler, then always call sendError >> in servlet if the incoming request response is >400. >> >> Can you try this out, and if it works I can look at getting it into >> Undertow. >> >> Stuart >> >> On Wed, 8 Jul 2020 at 02:35, Brad Wood <bdw429s(a)gmail.com&gt; wrote: >> >>> 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 >>>>>>>> >>>>>>>>