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xmldelphixsltdelphi-2007

How to transform an XML using an XSLT?

I have an XML file and an XSLT and I want to use the XSLT to trasform the XML into an HTML string which could be loaded into a TWebBrowser.

For my tests, I'm using these example files.

XML File:

<?xml version="1.0" encoding="UTF-8"?>
<breakfast_menu>

<food>
<name>Belgian Waffles</name>
<price>$5.95</price>
<description>Two of our famous Belgian Waffles with plenty of real maple syrup</description>
<calories>650</calories>
</food>

<food>
<name>Strawberry Belgian Waffles</name>
<price>$7.95</price>
<description>Light Belgian waffles covered with strawberries and whipped cream</description>
<calories>900</calories>
</food>

<food>
<name>Berry-Berry Belgian Waffles</name>
<price>$8.95</price>
<description>Light Belgian waffles covered with an assortment of fresh berries and whipped cream</description>
<calories>900</calories>
</food>

<food>
<name>French Toast</name>
<price>$4.50</price>
<description>Thick slices made from our homemade sourdough bread</description>
<calories>600</calories>
</food>

<food>
<name>Homestyle Breakfast</name>
<price>$6.95</price>
<description>Two eggs, bacon or sausage, toast, and our ever-popular hash browns</description>
<calories>950</calories>
</food>

</breakfast_menu>

XSLT File:

<?xml version="1.0" encoding="UTF-8"?>
<html xsl:version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<body style="font-family:Arial;font-size:12pt;background-color:#EEEEEE">
<xsl:for-each select="breakfast_menu/food">
  <div style="background-color:teal;color:white;padding:4px">
    <span style="font-weight:bold"><xsl:value-of select="name"/> - </span>
    <xsl:value-of select="price"/>
    </div>
  <div style="margin-left:20px;margin-bottom:1em;font-size:10pt">
    <p>
    <xsl:value-of select="description"/>
    <span style="font-style:italic"> (<xsl:value-of select="calories"/> calories per serving)</span>
    </p>
  </div>
</xsl:for-each>
</body>
</html>

Attempt 1:

I've found this solution and tried the function:

Uses
  XMLDoc, XMLIntf;

function Transform(XMLContent : string; XSLContent : string) : WideString;
var
  XML : IXMLDocument;
  XSL : IXMLDocument;
begin

  XML := LoadXMLData(XMLContent);
  XSL := LoadXMLData(XSLContent);

  XML.DocumentElement.TransformNode(XSL.DocumentElement, Result)

end;

But it produces an unexpected output:

Belgian Waffles$5.95Two of our famous Belgian Waffles with plenty of real maple syrup650Strawberry Belgian Waffles$7.95Light Belgian waffles covered with strawberries and whipped cream900Berry-Berry Belgian Waffles$8.95Light Belgian waffles covered with an assortment of fresh berries and whipped cream900French Toast$4.50Thick slices made from our homemade sourdough bread600Homestyle Breakfast$6.95Two eggs, bacon or sausage, toast, and our ever-popular hash browns950

Attempt 2:

I've found the following function in the "Using the MSXML Parser/ Transform Engine" section of this page (Note: it's a Delphi 5 example but I'm using Delphi 2007).

function DoTransform(const xml, xsl : string ): string;
var
  XMLDoc : IXMLDOMDocument;
  XSLDoc : IXMLDOMDocument;
  Template : IXSLTemplate;
  Processor : IXSLProcessor;
begin
  Result := '';
  try
    XMLDoc := CoFreeThreadedDOMDocument30.Create;
    XSLDoc := CoFreeThreadedDOMDocument30.Create;
    XMLDoc.load(xml);
    XSLDoc.load(xsl);
    Template := CoXSLTemplate30.Create;
    Template.stylesheet := XSLDoc;
    Processor := Template.createProcessor;
    Processor.input := XMLDoc;
    Processor.transform;
    result :=  Processor.output;
  finally
    XMLDoc := nil;
    XSLDoc := nil;
  end;
end;

I've imported the Microsoft XML type library...

Component -> Import Component -> Import a Type Library -> Next -> Microsoft XML, v6.0

...and added MSXML2_TLB to the uses clause but then some other errors occours:

E2003 Undeclared identifier: 'CoFreeThreadedDOMDocument30'

E2003 Undeclared identifier: 'CoXSLTemplate30'

I've switched CoFreeThreadedDOMDocument30 to CoFreeThreadedDOMDocument60 and CoXSLTemplate30 to CoXSLTemplate60 and now it compiles without errors.

At runtime, at this line:

Template.stylesheet := XSLDoc;

It raises the following exception (In italian):

Il foglio di stile non include un elemento documento. Il foglio di stile è vuoto oppure potrebbe essere un documento XML in formato non corretto.

In english it should be something like this:

The stylesheet doesn't include a document element. The stylesheet is empty or it could be a bad formatted XML document.

I've tested with other example files and the error is always the same and I don't understand which could be the problem.

Am I on the right way or are there better ways to do what I need?

Solution

  • This is my solution tested on Delphi 2007 and Delphi XE7.

    uses
  msxml; 

function Transform(const AXMLContent : string; const AXSLContent : string) : string;
var
  XML : IXMLDOMDocument;
  XSL : IXMLDOMDocument;
begin
  XML := CoDOMDocument.Create;
  XML.loadXML(AXMLContent);

  XSL := CoDOMDocument.Create;
  XSL.loadXML(AXSLContent);

  Result := XML.TransformNode(XSL);
end;

    picture of the resulting styled xml

    Resulting HTML code:

    <html>
<body style="font-family:Arial;font-size:12pt;background-color:#EEEEEE">
<div style="background-color:teal;color:white;padding:4px"><span style="font-weight:bold">Belgian Waffles - </span>$5.95</div>
<div style="margin-left:20px;margin-bottom:1em;font-size:10pt">
<p>Two of our famous Belgian Waffles with plenty of real maple syrup<span style="font-style:italic"> (650 calories per serving)</span></p>
</div>
<div style="background-color:teal;color:white;padding:4px"><span style="font-weight:bold">Strawberry Belgian Waffles - </span>$7.95</div>
<div style="margin-left:20px;margin-bottom:1em;font-size:10pt">
<p>Light Belgian waffles covered with strawberries and whipped cream<span style="font-style:italic"> (900 calories per serving)</span></p>
</div>
<div style="background-color:teal;color:white;padding:4px"><span style="font-weight:bold">Berry-Berry Belgian Waffles - </span>$8.95</div>
<div style="margin-left:20px;margin-bottom:1em;font-size:10pt">
<p>Light Belgian waffles covered with an assortment of fresh berries and whipped cream<span style="font-style:italic"> (900 calories per serving)</span></p>
</div>
<div style="background-color:teal;color:white;padding:4px"><span style="font-weight:bold">French Toast - </span>$4.50</div>
<div style="margin-left:20px;margin-bottom:1em;font-size:10pt">
<p>Thick slices made from our homemade sourdough bread<span style="font-style:italic"> (600 calories per serving)</span></p>
</div>
<div style="background-color:teal;color:white;padding:4px"><span style="font-weight:bold">Homestyle Breakfast - </span>$6.95</div>
<div style="margin-left:20px;margin-bottom:1em;font-size:10pt">
<p>Two eggs, bacon or sausage, toast, and our ever-popular hash browns<span style="font-style:italic"> (950 calories per serving)</span></p>
</div>
</body>
</html>

    For displaying the resulting string into a TWebBrowser I've used the following code:

    procedure LoadHTMLCode(AWebBrowser : TWebBrowser; const AHTMLCode: string);
var
  Doc: Variant;
begin
  if not Assigned(AWebBrowser.Document) then
    AWebBrowser.Navigate('about:blank');

  Doc := AWebBrowser.Document;
  Doc.Clear;
  Doc.Write(AHTMLCode);
  Doc.Close;
end;

    ...

    var
  XMLContent : string;
  XLSContent : string;
  HTMLCode : string;
begin
  //loading XML content
  XMLContent := ...;

  //loading XLS content
  XLSContent := ...;
 
  //transforming
  HTMLCode := Transform(XMLContent, XLSContent);

  //displaying
  LoadHTMLCode(WebBrowser1, HTMLCode);  
end;