XSLT Parameter parsing

[Maxim Dounin]

Hello!

[sorry for late reply, I have this flagged in my inbox but had no 
time to look at this closely]

On Fri, Jul 30, 2010 at 03:42:12PM +0100, Laurence Rowe wrote:

> XSLT parameter parsing currently allows paramters to be passed one per
> line or multiple per line separated by a colon (:).
> http://wiki.nginx.org/NginxHttpXsltModule#xslt_stylesheet
> 
>   location / {
>     xslt_stylesheet /site/xslt/one.xslt
>     $arg_xslt_params
>     param1='$value1': param2=value2
>     param3=value3;
>   }
> 
> This has the unfortunate effect of preventing xpath parameters being
> passed as url parameters when they contain a colon (fairly common in
> xpath as a namespace or axis specififer). Consider the following
> configuration:
> 
>   location / {
>     xslt_stylesheet filter.xsl
>     xpath=$arg_xpath;
>   }
> 
> I would like to be able to call call the url
> /doc.xml?xpath=ancestor-or-self::entry, but the current parameter
> parsing code interprets this as multiple invalid parameters
> ``xpath=ancestor-or-self``, ````, ``entry``. As far as I can tell
> there is no way to substitute ":" for "%3A" in a variable.
> 
> The attached patch removes support for specifying multiple parameters
> in a single line. You may still supply multiple parameters to an xslt
> by supplying one per line. (I've split the patch into two changesets
> for readability.)

I believe multiple parameters in single argument was initially introduced 
to make it possible to pass multiple params as single block.  E.g.
via query string argument:

    xslt_stylesheet    /site/xslt/one.xslt
                       $arg_xslt_params;

(part of example from 
http://sysoev.ru/nginx/docs/http/ngx_http_xslt_module.html#xslt_stylesheet)

I don't think that ripping this functionality just to make writing 
xpath arguments easier is a good idea.  Correct escaping for ':' 
should do the trick.

> As an alternative it may be possible to preserve the current behaviour
> by splitting parameters before the call to ngx_http_complex_value
> which performs the variable substitution, however I was unable to work
> out how to do this myself.

This aproach will prevent the above from working, too.

Maxim Dounin