Jetty 12 - Improve ErrorProcessor to handle error pages

[sbordet]

Jetty version(s)
12+

Description
It would be nice if ErrorProcessor (or a subclass) can be configured with a mapping between the HTTP status code and an error page, something like:

errorProcessor.addPage(404, "/404.html");

[gregw]

In order to do this, we would need an ErrorPageErrorProcessor extends ErrorProcessor that is aware of the server (or perhaps context). Either way, there are two ways to implement:

1. On every error process call the server.handle method is called to get a processor for the error page. This means there is a possible blocking call to Handler.handle before the processor is found.

2. During onStart, fake requests are used to call the server.handle method to pre-obtain processors for the error pages. This would avoid the blocking stage during process, but I'm not sure it would work for all processors... as the requests ultimately passed to the processor would be different instance to the request passed to obtain the processor. Any processor that retains the initial request (possibly wrapped) would not work.

So I think 2. is a non-starter and probably an over optimisation anyway. 1 it is then.

[sbordet]

@gregw left a feedback on the PR.

[github-actions]

This issue has been automatically marked as stale because it has been a
full year without activity. It will be closed if no further activity occurs.
Thank you for your contributions.

[github-actions]

This issue has been closed due to it having no activity.