[undertow-dev] More rewrite handler testing and questions

[Stuart Douglas]

Basically it was added for backward compatibility with JBoss Web.

Stuart

On Fri, 10 Jul 2020 at 06:48, Brad Wood <bdw429s at gmail.com> wrote:

> While I'm asking about rewrites, I should mention I have come across
> the io.undertow.servlet.compat.rewrite package, however
>
>    - It's not mentioned anywhere in the docs
>    - The code itself has no comments of any kind explaining it
>    - There's no handlerbuilder so it doesn't appear the RewriteHandler
>    can be used with Undertow's predicate language
>
> I am intrigued by it since it appears to be specifically written to fire
> in the servlet's handler chain and it appears to be a rather robust
> implementation, I just can't find any docs on how to use it!
>
> What is the backstory with Undertow core rewrite handler and servlet
> rewrite handler?
>
> Thanks!
>
> ~Brad
>
> *Developer Advocate*
> *Ortus Solutions, Corp *
>
> E-mail: brad at coldbox.org
> ColdBox Platform: http://www.coldbox.org
> Blog: http://www.codersrevolution.com
>
>
>
> On Thu, Jul 9, 2020 at 11:42 AM Brad Wood <bdw429s at gmail.com> wrote:
>
>> So, in my bid to put the predicate language through the paces, I've been
>> testing out all the rewrite rules I've ever used with mod_rewrite or Tuckey
>> Rewrite to see if Undertow's handlers are up to the task.
>>
>> I've run into an issue again with probably the most common rewrite rule
>> of any CFML app using an MVC framework, which is a rule that creates
>> so-called "SES" URLs and force all requests through a front controller
>> design pattern.
>>
>> Basically
>>
>> site.com/home/about
>>
>>
>> gets rewritten to
>>
>> site.com/index.cfm/home/about
>>
>>
>> Here you can see how this rule is typically accomplished in Apache httpd,
>> Nginx, IIS, and Tuckey:
>>
>>
>> https://coldbox.ortusbooks.com/the-basics/routing/requirements/rewrite-rules
>>
>>
>> The hang up is that* any incoming path that maps to an actual file*
>> skips the rewrite rule.  That way* /images/logo.jpg* doesn't get
>> rewritten.
>>
>> So here was my first stab at it with Undertow's predicate language-- it
>> seemed simple enough:
>>
>> not file and not directory -> rewrite('/index.cfm/%{RELATIVE_PATH}')
>>
>>
>> But our old friend the servlet of course is nowhere to be found since my
>> "file" and "directory" predicates were executing in the root handler chain
>> so there is no concept of a servlet's context root with which to resolve
>> file system paths.
>>
>> So basically, I understand exactly why this doesn't work, but I feel that
>> we need to find a way to make this work.  This is a feature that pretty
>> much every rewrite engine I've ever used has-- the ability to test the file
>> system to see if a file or directory exists.  Can we discuss the following
>> options?
>>
>>    - Find a way for the root handler chain to access the deployment's
>>    resource manager
>>    - Find a way for the rewrite handler to correctly affect not only the
>>    exchange but also (optionally) the HttpServletRequest so it's possible to
>>    rewrite the URL inside of the servlet's handler chain. I know for certain
>>    this is possible because the Tuckey Rewrite engine is implemented as a
>>    servlet filter.
>>
>> I would prefer the first option since I do like having the predicates in
>> the root handler chain so it can run as early as possible.
>>
>> Thanks!
>>
>> ~Brad
>>
>> *Developer Advocate*
>> *Ortus Solutions, Corp *
>>
>> E-mail: brad at coldbox.org
>> ColdBox Platform: http://www.coldbox.org
>> Blog: http://www.codersrevolution.com
>>
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