Changes to Response ignored in "runAsFinally"-filter on exception

[uldall]

I have created the following small test application:

public static void main(String... args) {
    Pippo pippo = new Pippo();
    pippo.GET("/hello/", routeContext -> {
    	routeContext.getResponse().ok();
    	throw new RuntimeException("Ouch");
    });
    pippo.ALL("/.*", routeContext -> {
        routeContext.getResponse().header("Cache-Control", "no-cache, no-store, must-revalidate");
	routeContext.getResponse().header("Pragma", "no-cache");
	routeContext.getResponse().header("Expires", "0");
	routeContext.next();
		
	System.out.println("Filter processed.");
    }).runAsFinally();
    pippo.start();
}

Which results in the following output when doing a GET on /hello/:

2017-02-07T09:07:50.438Z [XNIO-1 task-1] INFO  ro.pippo.core.PippoFilter - Pippo started (PROD)
2017-02-07T09:07:50.452Z [XNIO-1 task-1] ERROR ro.pippo.core.DefaultErrorHandler - Ouch
java.lang.RuntimeException: Ouch
	at com.gamblify.burgundy.content.Main.lambda$0(Main.java:22) ~[classes/:na]
	at ro.pippo.core.route.DefaultRouteContext.handleRoute(DefaultRouteContext.java:352) ~[pippo-core-1.1.0.jar:na]
...
Filter processed.

As the output shows the "/.*" filter is correctly called. The changes to the response is however ignored and so the HTTP headers are not added.

[decebals]

I understand what you say. Is it important the response state in this case (throw error)?
When a route handler throws an exception (your case), the error handler is called and after this, all finally routes are called. You can see here the code. The error handler commits the response (send a status code or an error page based on a template to the client) and from this perspective, any modification on Request or Response that are made by finally filters/routes ("after filters") are useless.
On "after filters", I do some business/logic operation (release or commit a database connection, ...).

[uldall]

What I am trying to achieve is to have a filter which will always add the no-cache HTTP headers. Errors or not. Is there a better way to achieve this?

Is seems a bit illogical that changing the Response sometimes works in the finally filters and sometimes doesn't.

[gitblit]

Set the no-cache headers in a filter that runs before your handler rather than trying to set them after your handler.

[decebals]

@uldall
Pippo doesn't reuse the Request, Response, RouteContext instances. On each request from browser/client, Pippo creates new instances for these types. I will try to improve the documentation.
As @gitblit says, you can achieve your objective using a "before filter" route.
It's enough to add below route as a "before filter" (a first route that precedes business routes)

ALL("/.*", routeContext -> routeContext.getResponse().noCache()).runAsFinally();