I'm in a similar situation in that I've spent the last 6 months cramming
XSLT in order to do output from an application provided by a vendor. In
my situation, I'm taking information stored in a CMS database as XML
fragments and transforming it into our Web site's pages. (The CMS is
called Cascade, and is okay, but not fantastic.)

The tricky part of this situation is that simply grabbing a book on
XPath and XSLT will not tell you everything you need to know in order to
work with your proprietary software. Neither will simply knowing what
language the middleware layer is written in. Specifically, you need to
find out from your vendor what XSLT processor their application. In my
case, I found out that my CMS uses Xalan, which impacts my situation
significantly, since it limits me to XSLT 1.0. However, the Xalan
processor does allow for one to script extensions, and in my case I
_might_ be able to leverage that fact to access some system information,
depending on what capabilities my vendor has given me. So, in short,
making the most of the development environment you have in creating your
XSLT will require you not only to grok the complexities of what I think
is a rather difficult language to master, but also to gain a good
understanding of what tools are and are not available to you through
your preprocessor. 

Just to address your original question, XSLT really is not designed to
work like a conventional programming language per-se. You may or may not
have direct access to environment variables. That is dependent upon how
the XSLT processor is implemented by your vendor. I did see some
creative ideas in other posts, and I do not know if they will or will
not work. However, it is often possible for the middleware layer to pass
data to the XSLT processor, thus exposing it to the XSLT developer.
However, what data gets passed to the XSLT developer is generally under
the control of the application developer.

Here is a quick example of how XML data and XSLT presentation logic can
be glued together in PHP using a non-native XSLT processor. This is
being done similarly by our respective Java applications, using
different XSLT processors, and hopefully a lot more error checking.

http://frenzy.marinlibrary.org/code-samples/php-xslt/middleware.php

In the example, I have passed some environment data to the XSLT
processor from the PHP middleware layer. As you will see, what data is
exposed is entirely determined by the PHP.

Good luck!

- David

---
David Cloutman <[log in to unmask]>
Electronic Services Librarian
Marin County Free Library 

-----Original Message-----
From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of
Doran, Michael D
Sent: Friday, June 19, 2009 2:53 PM
To: [log in to unmask]
Subject: Re: [CODE4LIB] How to access environment variables in XSL


Hi Dave,

> What XSLT processor and programming language are you using?

I'm embarrassed to say that I'm not sure.  I'm making modifications and
enhancements to already existing XSL pages that are part of the
framework of Ex Libris' new Voyager 7.0 OPAC.  This new version of the
OPAC is running under Apache Tomcat (on Solaris) and my assumption is
that the programming language is Java; however the source code for the
app itself is not available to me (and I'm not a Java programmer anyway,
so it's a moot point).  I assume also that the XSLT processor is what
comes with Solaris (or Tomcat?).  As you can probably tell, this stuff
is new to me.  I've been trying to take a Sun Ed XML/XSL class for the
last year, but it keeps getting cancelled for lack of students.
Apparently I'm the last person left in the Dallas/Fort Worth area that
needs to learn this stuff. ;-)

-- Michael

# Michael Doran, Systems Librarian
# University of Texas at Arlington
# 817-272-5326 office
# 817-688-1926 mobile
# [log in to unmask]
# http://rocky.uta.edu/doran/
  

> -----Original Message-----
> From: Code for Libraries [mailto:[log in to unmask]] On 
> Behalf Of Walker, David
> Sent: Friday, June 19, 2009 2:48 PM
> To: [log in to unmask]
> Subject: Re: [CODE4LIB] How to access environment variables in XSL
> 
> Micahael, 
> 
> What XSLT processor and programming language are you using?
> 
> --Dave
> 
> ==================
> David Walker
> Library Web Services Manager
> California State University
> http://xerxes.calstate.edu
> ________________________________________
> From: Code for Libraries [[log in to unmask]] On Behalf 
> Of Doran, Michael D [[log in to unmask]]
> Sent: Friday, June 19, 2009 12:44 PM
> To: [log in to unmask]
> Subject: [CODE4LIB] How to access environment variables in XSL
> 
> I am working with some XSL pages that serve up HTML on the 
> web.  I'm new to XSL.   In my prior web development, I was 
> accustomed to being able to access environment variables (and 
> their values, natch) in my CGI scripts and/or via Server Side 
> Includes.  Is there an equivalent mechanism for accessing 
> those environment variables within an XSL page?
> 
> These are examples of the variables I'm referring to:
>     SERVER_NAME
>     SERVER_PORT
>     HTTP_HOST
>     DOCUMENT_URI
>     REMOTE_ADDR
>     HTTP_REFERER
> 
> In a Perl CGI script, I would do something like this:
>     my $server = $ENV{'SERVER_NAME'};
> 
> Or in an SSI, I could do something like this:
>     <!--#echo var="REMOTE_ADDR"-->
> 
> If it matters, I'm working in: Solaris/Apache/Tomcat
> 
> I've googled this but not found anything useful yet (except 
> for other people asking the same question).  Maybe I'm asking 
> the wrong question.  Any help would be appreciated.
> 
> -- Michael
> 
> # Michael Doran, Systems Librarian
> # University of Texas at Arlington
> # 817-272-5326 office
> # 817-688-1926 mobile
> # [log in to unmask]
> # http://rocky.uta.edu/doran/
> 

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