How to do a XSLT transformation in FreePascal?
lazarus / 62-General

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kirchfritz · 2011-06-01 10:05

Any ideas or code snippets of how to do a simple XSLT Transformation,
given a XML and a XSLT-stylesheet?

Without calling XSLTProc.EXE as an external Process! Please!

Fritz

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Arbee · 2011-06-01 13:06

Can't you use the libxslt library directly in Lazarus?  afaik xsltproc
basically does that too.

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kirchfritz · 2011-06-01 14:56

Sorry I am a newbie in Freepascal.
Do you have codesamples how to use libxslt library in FreePascal?

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Arbee · 2011-06-02 09:48

I do not have examples in FPC.  You can get information on libxslt
(and I guess that in its turn needs libxml) here
http://xmlsoft.org/XSLT/. 

libxml already has a Pascal wrapper.  Don't know about libxslt.

It is a C library, but I would assume it comes as a DLL in the Windows
version.  Or if not, could be moulded into one.  Perhaps you can start
a project to translate it into Pascal?

by the way ... why is a detour via xsltproc or via another parser like
saxon out of the question?

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kirchfritz · 2011-06-03 12:34

I dont want to torture the enduser with requirements like
"You need saxon version xyz"
or
"You need XSLTPROC.EXE"
or
"You need Java Virtual machine version x.y.z"

Give the enduser a single EXE together with an INI-file is the ideal
way for me.
That's why I want to do the XSLT transformation inside my
FreePascal/Lazarus program without calling external resources.

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Rave · 2011-06-03 21:46

Can't you just distribute XSLTPROC.EXE alongside with program?

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williamda · 2011-09-19 14:47

If you are compiling for Windows, you can use MSXML via ActiveX that
is always included in Windows.

Here is an example:


function ApplyStylesheet( DocumentFile: String; const XSLTFile:
String): String;
var
  Doc, XSL: Variant;
begin
  XSL := CreateOleObject('MSXML.DOMDocument');
  Doc := CreateOleObject('MSXML.DOMDocument');

  oc.Load( DocumentFile );
  XSL.Load( XSLTFile );

  Result := Doc.transformNode(XSL);
end;

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marcov · 2011-09-21 10:28

Quote from: williamda on September 19, 2011, 04:47:52 pmIf you are
compiling for Windows, you can use MSXML via ActiveX that is always
included in Windows.

Beware: Afaik the one that comes with original XP is buggy.

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williamda · 2011-09-28 14:41

There is a very good parser library based in libxml2 called idom2-pas
http://idom2-pas.sourceforge.net/

It´s DOM based and compatible with Windows MSXML DOM.

It compiles in lazarus with very few changes and it´s cross platform.

You only have to include some DLL/SO with your application.

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kirchfritz · 2011-12-03 16:23

I tried this:

Code: [Select]program MyApp;

{$mode objfpc}{$H+}

uses
  Classes, SysUtils,  COMObj;

{$R *.res}

  function ApplyStylesheet( DocumentFile: String; const XSLTFile:
String): String;
  var
    Doc, XSL: Variant;
  begin
    XSL := CreateOleObject('MSXML.DOMDocument');
    Doc := CreateOleObject('MSXML.DOMDocument');

    Doc.ValidateOnParse := True;
    Doc.Async := False;
    XSL.ValidateOnParse := True;
    XSL.Async := False;

    XSL.Load( XSLTFile );
    Doc.Load( DocumentFile );

    Result := Doc.transformNode(XSL);
  end;

begin
  if ParamCount <> 2 then
  begin
    writeln('Usage:');
    writeln('Application <xml> <xslt>');
    halt;
  end;
  if not fileExists(ParamStr(1)) then
  begin
    writeln('XML not found: ',ParamStr(1));
    halt;
  end;
  if not fileExists(ParamStr(2)) then
  begin
    writeln('XSLT not found: ',ParamStr(2));
    halt;
  end;
  Writeln(applyStylesheet(ParamStr(1),ParamStr(2)));
end.
     

It compiles without error, but at run time program aborts with error
message: Stylesheet is empty.
I am abolutely sure that my stylesheet is not empty.

Can anybody help me to find my error?

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Laksen · 2011-12-03 17:01

Looks like a bug in FPC since the following works:
Code: [Select]  function ApplyStylesheet( DocumentFile: String; const
XSLTFile: String): String;
  var
    Doc, XSL,t: Variant;
  begin
    XSL := CreateOleObject('MSXML.DOMDocument');
    Doc := CreateOleObject('MSXML.DOMDocument');

    Doc.ValidateOnParse := True;
    Doc.Async := False;
    XSL.ValidateOnParse := True;
    XSL.Async := False;

    t := XSLTFile;
    XSL.load( t );
    t := DocumentFile;
    Doc.load( t );

    Result := Doc.transformNode(XSL);
  end;

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evresis · 2022-04-21 10:17

To avoid runtime xslt errors add this

  var result : widestring;
        ft:text;
       err:variant;
     aFileName:string;
    
  aFileName:='myoutput';
  if (XSL.parseError.errorCode <> 0) then begin
      Err := XSL.parseError;
      writeln('XSL error ' + Err.reason);
    end else begin
     Result:=Doc.transformNode(XSL);
     assign(ft,aFileName);
     rewrite(ft);
     write(ft,result);
     close(ft);
   end;