Item5914: TWiki::Request::url() must support -rewrite, -absolute and -relative

Item2525 and Item5408 are enough evidence that TWiki::Request::url() must support -rewrite, -absolute and -relative and achieve complete CGI.pm compatibility.

-- TWiki:Main/GilmarSantosJr - 10 Aug 2008

-absolute support is easy to add (it's the same as $TWiki::cfg{ScriptUrlPaths}{$action} or $TWiki::cfg{ScriptUrlPath}/$action), since -rewrite is not added. The problem with -rewrite is that it depends on REQUEST_URI environment variable, that is not CGI-standard (working with the assumption that it's present cuts portability [not all webservers would implement and give the same semantics to it] and ties TWiki to CGI engine).

Item5408 is not specific why TablePlugin should be aware of rewrites and I can't figure out a good reason.

-- TWiki:Main/GilmarSantosJr - 11 Aug 2008

I added support for -absolute. I thought about -rewrite and IMHO admins should set $TWiki::cfg{ScriptUrlPath} and related according to their setups (with or without redirects). If we add a dependency on REQUEST_URI variable, things will work on Apache and CGI, but there's no guarantee about other webservers and engines. So, I choose portability and standards-compliance. Waiting for feedback from TWiki community.

-- TWiki:Main/GilmarSantosJr - 11 Aug 2008

This is one we need to discuss at a release meeting.

-- TWiki:Main.KennethLavrsen - 18 Sep 2008

I'll try to add support for -rewrite if the web server defined REQUEST_URI. I hope that all web servers that support rewrite rules also defines the non-standard REQUEST_URI (and I hope all of them use the same semantics). Probably it's fair to assume this, since CGI works this way.

-- TWiki:Main.GilmarSantosJr - 04 Oct 2008

I've studied CGI code a lot to understand -rewrite option. It takes place when REQUEST_URI doesn't begin with SCRIPT_NAME. That makes sense, except that I simply couldn't reproduce such a situation. I played with apache mod_rewrite a lot and always the REQUEST_URI starts with SCRIPT_NAME, I mean, -rewrite code is not executed.

Then I realized that even if I could reproduce this situation, it would not be that useful: I could generate correct links for the same script that is being executed, but not others. That's why $TWiki::cfg{ScriptUrlPath} and $TWiki::cfg{ScriptUrlPaths}{*} exist, so I generate URL's based on those settings (I also ignore SCRIPT_NAME, or almost this: I use it only to set $request->action). Those settings should be adjusted by admins considering rewrite rules.

TWiki:Main.RafaelAlvarez showed a situation that this mechanism doesn't work well: TWiki is installed behind a corporate firewall. Internally it is accessed using one URL. Externally another. If I generated URLs based on SCRIPT_NAME, then they would work well only for the action in use (I would correctly generate view when a topic was being viewed and correct edit when being edited), that is not enough IMHO.

So I'm closing this item with this limitation, that is not only on TWiki::Request but also in the way TWiki generates its URLs.

A possible solution for cases like Rafael's would be to make it possible to adjust $TWiki::cfg{ScriptUrlPath} based on the HTTP_HOST, for example (if the internal access is made using a virtual host different from external accesses), but then it's not a bug but a feature proposal.

-- TWiki:Main.GilmarSantosJr - 05 Oct 2008

Setting to Closed, since it's about new code.

-- GilmarSantosJr - 08 Jan 2009