msxml - Dave's Blog

XSL Identity Transfom

2007 Oct 12, 4:08As noted in the XSL Transformations spec you can create the identity transform using the xsl:copy element. With the MSXML implementation of xsl:copy the example the spec gives produces slightly ugly elements. For instance given it produces . In order to ensure empty elements turn out pretty I've modified the example as follows:

This got me thinking about inverting XSLTs. Clearly in general an XSLT isn't invertible since an XSLT can completely ignore the input XML and produce something else entirely but then the above is an example of an XSLT that is invertible. So there is a subset of XSLTs that are invertible, how might you produce the inverse of an XSLT, and would this ever be useful?xml msxml inverse xlst xsl

XSL Transforms in JavaScript

2007 Oct 7, 4:12In a previous post I mentioned an xsltproc like js file I made. As noted in that post, on Windows you can write console script files in JavaScript, name them foo.js, and execute them from the command prompt. I later found that MSDN has an XSLT javascript sample which looks similar to mine, but I like mine better for the XSLT parameter support and having a non-ridiculous way of interpreting filenames. The code for my xsltproc.js follows. The script is very simple and demonstrates the ease with which you can manipulate these system objects and all it takes is opening up notepad.

var createNewXMLObj = function() {
   var result = new ActiveXObject("MSXML2.FreeThreadedDOMDocument");
   result.validateOnParse = false;
   result.async = false;
   return result;
}

var args = WScript.arguments;
var ofs = WScript.CreateObject("Scripting.FileSystemObject");

var xslParams = [];
var xmlStyle = null;
var xmlInput = null;
var inputFile = null;
var outputFile = null;
var error = false;

for (var idx = 0; idx < args.length && !error; ++idx)
   if (args.item(idx) == "-o") {
      if (idx + 1 < args.length) {
         outputFile = ofs.GetAbsolutePathName(args.item(idx + 1));
         ++idx;
      }
      else
         error = true;
   }
   else if (args.item(idx) == "--param" || args.item(idx) == "-param") {
      if (idx + 2 < args.length) {
         xslParams[args.item(idx + 1)] = args.item(idx + 2);
         idx += 2;
      }
      else
         error = true;
   }
   else if (xmlStyle == null) {
      xmlStyle = createNewXMLObj();
      xmlStyle.load(ofs.GetAbsolutePathName(args.item(idx)));
   }
   else if (xmlInput == null) {
      inputFile = ofs.GetAbsolutePathName(args.item(idx));
      xmlInput = createNewXMLObj();
      xmlInput.load(inputFile);
   }

if (xmlStyle == null || xmlInput == null || error) {
   WScript.Echo('Usage:\n\t"xsltproc" xsl-stylesheet input-file\n\t\t["-o" output-file] *["--param" name value]');
}
else {
   var xslt = new ActiveXObject("MSXML2.XSLTemplate.3.0");
   xslt.stylesheet = xmlStyle;
   var xslProc = xslt.createProcessor();
   xslProc.input = xmlInput;

   for (var keyVar in xslParams)
      xslProc.addParameter(keyVar, xslParams[keyVar]);

   xslProc.transform();

   if (outputFile == null)
      WScript.Echo(xslProc.output);
   else {
      var xmlOutput = createNewXMLObj();
      xmlOutput.loadXML(xslProc.output);
      xmlOutput.save(outputFile);
   }
}

js xml jscript windows xslt technical xsltproc wscript xsl javascript

XPointer Framework - IE7 XML Source View Upgrade Part 3

2007 May 17, 5:16Previously I created some resource tools and then I used them to overwrite msxml3's XML source view. In this update I've added support for the XPointer Framework.

This time around I've started to add support for the XPointer Framework to my XML source view and I've added installation instructions. The framework consists of a series of pointer segments each of which has a scheme name followed by data in parenthesis. For example 'scheme1(data1)scheme2(data2)scheme3(data3)'. A pointer segment resolves to a portion of the XML document based on the data and the scheme name. The whole pointer resolves to the first segment that successfully resolves. That is, from the example, if scheme1 resolves to nothing and scheme2 resolves to something then that's used and scheme3 is ignored. In addition to the framework I've added support for the xmlns scheme which binds namespace prefixes to a namespace URI and the element scheme which is a simple way to resolve to particular elements in an XML. I also have limited support for the xpointer scheme the content of which is resolved as an XPath with some extra functions (which I don't support -- hence the limited). I've also thrown in schemes for the two SelectionLanguage values supported by msxml3.

Next time I might try to support the xpointer functions that aren't in xpath using msxml script. But I think I'm losing steam on this project... we'll see.resource technical xml xpointer res xpath xslt

New XSLT - IE7 XML Source View Upgrade Part 2

2007 May 11, 8:55Last time, I had written some resource tools to allow me to view and modify Windows module resources in my ultimate and noble quest to implement the XML content-type fragment in IE7. Using the resource tools I found that MSXML3.DLL isn't signed and that I can replace the XSLT embedded resource with my own, which is great news and means I could continue in my endevour. In the following I discuss how I came up with this replacement for IE7's XML source view.

At first I thought I could just modify the existing XSLT but it turns out that it isn't exactly an XSLT, rather its an IE5 XSL. I tried using the XSL to XSLT converter linked to on MSDN, however the resulting document still requires manual modification. But I didn't want to muck about in their weird language and I figured I could write my own XSLT faster than I could figure out how theirs worked.

I began work on the new XSLT and found it relatively easy to produce. First I got indenting working with all the XML nodes represented appropriately and different CSS classes attached to them to make it easy to do syntax highlighting. Next I added in some javascript to allow for closing and opening of elements. At this point my XSLT had the same features as the original XSL.

Next was the XML mimetype fragment which uses XPointer, a framework around various different schemes for naming parts of an XML document. I focused on the XPointer scheme which is an extended version of XPath. So I named my first task as getting XPaths working. Thankfully javascript running in the HTML document produced by running my XSLT on an XML document has access to the original XML document object via the document.XMLDocument property. From this this I can execute XPaths, however there's no builtin way to map from the XML nodes selected by the XPath to the HTML elements that I produced to represent them. So I created a recursive javascript function and XSLT named-template that both produce the same unique strings based on an XML node's position in the document. For instance 'a3-e2-e' is the name produced for the 3rd attribute of the second element of the root element of the XML document. When producing the HTML for an XML node, I add an 'id' attribute to the HTML with the unique string of the XML node. Then in javascript when I execute an XPath I can discover the unique string of each node in the selected set and map each of them to their corresponding positions in the HTML.

With the hard part out of the way I changed the onload to get the fragment of the URI of the current document, interpret it as an XPath and highlight and navigate to the selected nodes. I also added an interactive floating bar from which you can enter your own XPaths and do the same. On a related note, I found that when accessing XML files via the file URI scheme the fragment is stripped off and not available to the javascript.

The next steps are of course to actually implement XPointer framework parsing as well as the limited number of schemes that the XPointer framework specifies.xml xpointer msxml res xpath xslt resource ie7 technical browser ie xsl

Resource Tools - IE7 XML Source View Upgrade Part 1

2007 May 9, 4:15I read about text/xml URI fragment resolution a few months ago. I was interested to find another kind of fragment reference other than the text/html URI fragment but of course I didn't find an implementation in IE, Firefox, or Opera. I decided to see how much work would be required to implement this in IE.

In IE and Firefox when you open an XML file that doesn't have an XML stylesheet the XML source is rendered with syntax highlighting. In IE I also noticed that the gold bar appears when you open an XML file off of your local machine. To me this suggested that the XML source was being rendered as HTML which I assumed was produced by running an XSLT on the source XML file. If so, I figured I could modify the XSLT to implement text/xml URI fragments. I ran FileMon to see if iexplore.exe loaded an XSLT file when opening an XML file. Only the XML file and MSXML3.DLL were opened and no XSLTs were loaded as files. My next hope for modifying the XSLT was if it existed as a resource in MSXML3.DLL. I did a findstr on the DLL for SCRIPT and found an XSLT so I decided to check for resources in MSXML3.DLL. Unfortunately my previous resource viewer didn't work correctly so I decided to write my own.

I created resource tools to view and modify resources in Windows modules. The viewer outputs HTML with links to the individual resources of a module using the res URI scheme that's built into IE. The modifier is a simple command line tool that replaces or adds one resource at a time to a module.

Using these tools I found that the XSLT was stored as a resource in MSXML3.DLL. I'll talk more about the existing XSLT and the one I replaced it with next time.resource technical xml msxml res xslt xsl