Re: simple redraft Re: Environment Variable Retrieval Spec

"John L. Clark" <[email protected]> Fri, 17 Feb 2006 12:22:26 -0800

Newsgroups	gmane.text.xml.xslt.extensions
Message-ID	<20060217202226.GZ10347@rejoice>

On Fri, Feb 17, 2006 at 01:37:57PM +0100, James Fuller wrote:
> > I think it would be better to structure the namespace, i.e
> > .../system/environment.

> I agree.

That's fine.  It was a relatively arbitrary decision, primarily meant to
be consistent with our other namespaces.

I've made the change in the spec, as well as a couple other fixes and
clarifications.  The new draft should be attached to this email, as well
as the HTML-formatted user page.

Take care,

    John L. Clark

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sys.xml (text/plain, 2.8 KB)

<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="../style/module.stylesheet.xsl" ?>
<exslt:module xmlns:exslt="http://exslt.org/documentation"
              version="1" prefix="sys">

<exslt:name>System</exslt:name>

<rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
                 xmlns:dc="http://purl.org/dc/elements/1.1/"
                 ID="sys">
  <dc:subject>EXSLT</dc:subject>
  <dc:subject>system</dc:subject>
  <dc:subject>module</dc:subject>
  <exslt:revision>
    <rdf:Description xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
                     xmlns:dc="http://purl.org/dc/elements/1.1/"
                     ID="sys.1">
      <exslt:version>1</exslt:version>
      <dc:creator>John L. Clark</dc:creator>
      <dc:date>2006-02-15</dc:date>
      <dc:description>Specify a namespace for access to environment variables.</dc:description>
    </rdf:Description>
  </exslt:revision>
</rdf:Description>

<exslt:doc xmlns="http://www.w3.org/1999/xhtml">
  <div>
    <p><em>EXSLT - System</em> provides features for using the host
    system.</p>

    <p>This module defines an additional namespace,
    <code>http://exsl.org/system/environment</code>, through which a user
    can access system environment variables via the <a
    href="http://www.w3.org/TR/xslt.html#function-system-property"><code>system-property</code></a>
    function.</p>

    <p>Use this namespace as follows.  Given <code>SQ</code>, a string that
    is a <a href="http://www.w3.org/TR/REC-xml-names#NT-QName">QName</a>
    with a prefix that maps to
    <code>http://exsl.org/system/environment</code> and local part
    <code>L</code>, <code>system-property(SQ)</code> returns the value of
    the system environment variable <code>L</code>.  For example, if
    "<code>env</code>" maps to this namespace, then
    <code>system-property("env:USER")</code> might return "john".</p>

    <p>The result of a call to system-property("env:X") MUST always return
    the same value (for a given X) throughout the processing session.  Which
    environment variables are available to a given XSLT transformation is
    system- and implementation-dependent, and an implementation SHOULD
    document any special steps it takes when exposing environment variables.
    Whenever an implementation cannot provide a value for a given
    environment variable, it MUST return the zero-length string as the
    result of the <code>system-property</code> call.  The mapping of the
    encoding of the variable's original value to that of the XPath string
    object is implementation-dependent.</p>

    <p><strong>Note:</strong> Retrieving environment variables can pose a
    security risk if those environment variables expose sensitive system
    information.</p>
  </div>
</exslt:doc>

</exslt:module>

index.html (text/html, 4.8 KB)

<?xml version="1.0" encoding="ISO-8859-1"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "/schema/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"><head><title>EXSLT - System</title><link href="http://exslt.org/base.css" rel="stylesheet"/></head><body><h1 id="#title"><a href="http://www.exslt.org/">EXSLT</a> - <a href="http://www.exslt.org/sys/">System</a></h1><table><tr><td id="menu"><p class="level1"><a href="sys.html">Implementer Page</a></p><p class="level1"><a href="../howto.html">How To</a></p><p class="level1"><a href="../download.html">Downloads</a></p><p class="level1">Modules</p><p class="level2"><a href="../date/index.html">Dates and Times</a></p><p class="level2"><a href="../dyn/index.html">Dynamic</a></p><p class="level2"><a href="../exsl/index.html">Common</a></p><p class="level2"><a href="../func/index.html">Functions</a></p><p class="level2"><a href="../math/index.html">Math</a></p><p class="level2"><a href="../random/index.html">Random</a></p><p class="level2"><a href="../regexp/index.html">Regular Expressions</a></p><p class="level2"><a href="../set/index.html">Sets</a></p><p class="level2"><a href="../str/index.html">Strings</a></p><p class="level2"><a href="../sys/index.html">System</a></p><p class="level1"><a href="../submissions/">Submissions</a></p><p class="level1"><a href="../list">Mailing List</a></p><p class="level1"><a href="../contact.html">Contact</a></p></td><td id="content"><p><b>Implementer Page: </b><a href="sys.html">sys.html</a><br/><b><a href="../howto.html#module-level">Module Package</a>: </b><a href="sys.zip">sys.zip</a></p><div><p><em>EXSLT - System</em> provides features for using the host
    system.</p><p>This module defines an additional namespace,
    <code>http://exsl.org/system/environment</code>, through which a user
    can access system environment variables via the <a href="http://www.w3.org/TR/xslt.html#function-system-property"><code>system-property</code></a>
    function.</p><p>Use this namespace as follows.  Given <code>SQ</code>, a string that
    is a <a href="http://www.w3.org/TR/REC-xml-names#NT-QName">QName</a>
    with a prefix that maps to
    <code>http://exsl.org/system/environment</code> and local part
    <code>L</code>, <code>system-property(SQ)</code> returns the value of
    the system environment variable <code>L</code>.  For example, if
    "<code>env</code>" maps to this namespace, then
    <code>system-property("env:USER")</code> might return "john".</p><p>The result of a call to system-property("env:X") MUST always return
    the same value (for a given X) throughout the processing session.  Which
    environment variables are available to a given XSLT transformation is
    system- and implementation-dependent, and an implementation SHOULD
    document any special steps it takes when exposing environment variables.
    Whenever an implementation cannot provide a value for a given
    environment variable, it MUST return the zero-length string as the
    result of the <code>system-property</code> call.  The mapping of the
    encoding of the variable's original value to that of the XPath string
    object is implementation-dependent.</p><p><strong>Note:</strong> Retrieving environment variables can pose a
    security risk if those environment variables expose sensitive system
    information.</p></div><p>
      XSLT processors may support any number of the extension elements and functions given in this module.
   </p><p class="note">
      Using EXSLT will only make your stylesheet portable amongst the implementations that support EXSLT. Note that there is no requirement for XSLT processors that are compliant to XSLT to support the extensions described within EXSLT.
   </p><h2>Namespace</h2><p>
      The namespace for EXSLT - System is:
   </p><pre>http://exslt.org/system</pre><p>
      Throughout this document, the prefix <code>sys</code> is used to refer to this namespace. Any other prefix can be used within a particular stylesheet (though a prefix must be specified to enable the extension functions to be recognised as extensions).
   </p><p>
      To use these extensions, you need to declare this namespace as an extension namespace in your stylesheet.  If your processor supports this module, then that's all you need to do, but if it doesn't, then you need to use a specific third-party implementation or the module stylesheet.  Typically, your stylesheet will look like:
   </p><pre>
&lt;xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:sys="http://exslt.org/system"
                extension-element-prefixes="sys"&gt;

&lt;xsl:import href="sys.xsl" /&gt;

...
              
&lt;/xsl:stylesheet&gt;
</pre></td></tr></table><div id="colophon"><p><a href="http://www.exslt.org/sys/index.html">http://www.exslt.org/sys/index.html</a> last modified 2006-02-15</p></div></body></html>

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