Let me repeat a small comment I already sent to Mike in private email:
in a J2EE environment, information that characterizes a request (such as
path, remote addr, etc.) is not accessible in environment variables or
properties, unlike in a CGI environment. That means that even if you write
an extension for XALAN-J to trigger the execution of your Java code while
processing a stylesheet during a request, you don't normally obtain access
to this information. Rather it is passed by the servlet container to the
servlet via a request object. If you don't control the servlet code - say
because it's vendor-provided - then you have to either rely on any extension
functionality the vendor may provide, or you have to create your own servlet
that wraps the vendor's servlet, saving the request information somewhere
where your xalan extension can retrieve it, then forwards the request to the
vendor's servlet.

 - Godmar


On Tue, Jun 23, 2009 at 2:04 PM, Cloutman, David
<[log in to unmask]>wrote:

> 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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