Can you give a bigger picture of exactly what you are trying to solve?
Where will your actual routing logic live?
What types of things are you expecting the predicate language to accomplish
for you?
Why do you need to be tied to servlets?
path(/box.json)->response-code(404)
This example seems pretty impractical because if you just left
the line out
entirely then wouldn't your router decide this route doesn't exist and
handle the 404 in your servlet code?
With attributes and custom HttpHandlers you should be able to accomplish
pretty much anything you want is there a specific need to have some of this
logic live in servlets?
On Fri, Jul 3, 2020 at 3:20 AM Brad Wood <bdw429s(a)gmail.com> wrote:
> So what is our solution here? It seems I'm darned if I do and darned if I
> don't.
> If I move the predicates until after the servlet then I
can call
> sendError() on the servlet response to trigger the error pages, however I
> lose the ability to rewrite the request (a deal breaker)
> But if I leave the predicates before the servlet, I can
perform rewrites,
> but I can no longer call sendError() since, as you said, there is no
> servlet response yet!
> I understand the separation between the servlet and core,
but it's killing
> me here. This seems like such a simple concept.
> - I have a servlet deployment with error page
configured
> - I want to have a predicated handler that uses the configured error
> pages
> Can I accomplish this with a default response listener
that accesses the
> error page configuration and dispatches the appropriate location? Even
> that feels dirty. It seems there should be a handler invoked directly from
> the predicates that can dispatch the error pages configured in the
> servlet. Even if all it did was look up the corresponding location for the
> given status code and forward the request there. But I can't even figure
> out how to access the deployment from the exchange.
> 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 9:22 PM Stuart Douglas <sdouglas(a)redhat.com> wrote:
>
>
>>
On Fri, 3 Jul 2020 at 10:34, Brad Wood <bdw429s(a)gmail.com> wrote:
>
>>> Before I give that workaround a try, a couple
existential questions...
>>
>>> - Should the
*response-code* handler also set the *errorCode* as
>>> well in the servlet request context so it triggers the doErrorDispatch()
>>> action?
>>> - Or should there be another built-in handler called
"send-error" or
>>> similar that does this.
>>
>>> Ex:
>>> path( /secret.json ) -> send-error ( 404 )
>>> path( /admin/ ) -> send-error( 503 )
>>
>>> I'm sort of
questioning what the usefulness is of the *response-code*
>>> handler however (at least in the context of the predicate language) if
it's
>>> default behavior is NOT to trigger the error code and therefore the error
>>> page.
>>
>
>>
These error pages are part of Servlet, while the predicate language is
>> part of core. The response-code handler does not really know anything about
>> the Servlet deployment.
>
>> Generally the predicate language is run before Servlet
(e.g. in WildFly),
>> so the HttpServletRequest/Response has not been created yet. This gives a
>> lot of flexibility in that you can make changes to route the request to
>> different contexts and potentially skip servlet altogether, but the down
>> side is that it is not tightly integrated with Servlet.
>
>> Stuart
>
>
>>
>>> 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
>>> 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>
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
>>>>> 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> 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
>>>>>
>>>>>>
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