SSI capture group result extraction

[Olaf Doschke]

Let's see if someone still is doing SSI here. Just out of curiosity I try to create a little building block templating just using SSI #includes.

<!--#set var="keyvaluepairs" value="key1=value1&key2=value2" -->
<!--#if expr="v('keyvaluepairs')=~/\bkey2=([a-zA-Z0-9]*)/" -->
<!--#set var="match" value="$0" -->
<!--#set var="key2" value="$1" -->
<!--#echo var="match" -->
<!--#echo var="key2" -->
<!--#endif -->

You can imagine finally this is about processing v('QUERY_STRING') later instead of keyvaluepairs.

I expected key1 to contain "value1" only, it should be the capturing group defined by parenthesis in the regex: ([a-zA-Z0-9]*) after the constant "key1=" part of the regex.
Instead $1 is empty.

So is there something wrong with how the current version (Apache/2.4.10) processes regex?

Bye, Olaf.

 

[feherke]

Hi

I did not used SSI for looong time. And a couple of versions.

So I would go the old way :

[b]SSILegacyExprParser[/b] on

<!--[b]#set[/b] var=[i]"keyvaluepairs"[/i] value=[i]"key1=value1&key2=value2"[/i] -->
<!--[b]#if[/b] expr=[i]"[highlight]$[/highlight]keyvaluepairs = /[highlight](?:^|&)[/highlight]key2=([a-zA-Z0-9]*)/"[/i] -->
<!--[b]#set[/b] var=[i]"match"[/i] value=[i]"$0"[/i] -->
<!--[b]#set[/b] var=[i]"key2"[/i] value=[i]"$1"[/i] -->
<!--[b]#echo[/b] var=[i]"match"[/i] -->
<!--[b]#echo[/b] var=[i]"key2"[/i] -->
<!--[b]#endif[/b] -->

Regarding your original code, I have no idea whether this applies to it or not :

Regular expression backreferences

The strings [tt]$0[/tt] ... [tt]$9[/tt] allow to reference the capture groups from a previously executed, successfully matching regular expressions. They can normally only be used in the same expression as the matching regex, but some modules allow special uses.

( Expressions in Apache HTTP Server | Other | Regular expression backreferences )

Maybe is intended behavior.

Feherke.
feherke.ga

 

[Olaf Doschke]

Thanks Feherke,

at least that works in legacy mode and since SSILegacyExprParser can be set per directory I should be able to control it.

It can't be the limitation, $0..$9 normally only are usable within the same expression. At least $0 works giving the overall match. I wonder, whether ap_expr syntax changed how capture groups have to be marked, though that should be reglar expression standard syntax.

Bye, Olaf.