Re: [xslt] extending xsltproc with plugins

[Tony Graham <Tony Graham MenteithConsulting com>]

On Tue, Jan 15 2008 11:24:14 +0000, gr active-media-group com wrote:
> First of all, thanks for your help Tony

Not a problem.

> I can compile and run test, with the supplied testplugin.c there's not 
> problem, but when I tryed to add a function to the file i run in this error:
>
> command:
> LIBXSLT_PLUGINS_PATH=/home/gr/Plugins < "./plugin.xml" xsltproc "./plugin.xsl" 
> - > result.xml
>
> error:
> xmlXPathCompOpEval: function DataDetailValue not found
> XPath error : Unregistered function
> runtime error: file ./plugin.xsl line 11 element value-of
> XPath evaluation returned no result.
>
> where in LIBXSLT_PLUGINS_PATH is the xmlsoft_org_xslt_testplugin.so library.

Declaring the function looks okay to me, though I'm not so sure about
the internals of the function.

Have you tried a version of getDataDetailValue() that just does the same
as xsltExtFunctionTest (though maybe with popping more function
arguments)?

> Here is the cose I added:
>
> static void getDataDetailValue(xmlXPathParserContextPtr ctxt, int nargs){
> 	
> 	char* parameters[6] = {"novalue\n", "novalue\n", "novalue\n", 
> 			"novalue\n", "novalue\n", "novalue\n"};
> 	char* msg = ",DataDetailValue";
> 	
> 	int var;
> 	for (var = 0; var < nargs; ++var) {
> 		xmlXPathObjectPtr obj = valuePop(ctxt);

If you want the string value, you can use xmlXPathPopString() [1]

> 		msg = concat(msg, ",");
> 		msg = concat(msg, (char*) obj);
> 		xmlXPathFreeObject(obj);
> 	}
> 	
> 	concat(msg,"\n");

Previously you used the return value of this function.

> 	parameters[0] = msg;
> 	
> 	char* result = sendDataBySocket(parameters);
> 	
> 	valuePush(ctxt, xmlXPathNewString(result));

Don't you need to free one or more of the versions of msg?

> }
>
> and this is the registration of the function:
>
> void
> PLUGINPUBFUN xmlsoft_org_xslt_testplugin_init(void)
> {
>     xsltRegisterExtModuleFull((const xmlChar *) XSLT_TESTPLUGIN_URL,
>                               xsltExtInitTest, xsltExtShutdownTest,
>                               xsltExtStyleInitTest,
>                               xsltExtStyleShutdownTest);
>     xsltRegisterExtModuleFunction((const xmlChar *) "testplugin",
>                                   (const xmlChar *) XSLT_TESTPLUGIN_URL,
>                                   xsltExtFunctionTest);
>     xsltRegisterExtModuleFunction((const xmlChar *) "DataDetailValue",
>                                   (const xmlChar *) XSLT_TESTPLUGIN_URL,
>                                   getDataDetailValue);
>     xsltRegisterExtModuleElement((const xmlChar *) "testplugin",
>                                  (const xmlChar *) XSLT_TESTPLUGIN_URL,
>                                  xsltExtElementPreCompTest,
>                                  xsltExtElementTest);
> }

Regards,


Tony Graham.
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[1] http://xmlsoft.org/html/libxml-xpathInternals.html#xmlXPathPopString