Re: [xml] Set Default Namespace

["Martin (gzlist)" <gzlist googlemail com>]

On 25/08/2008, Niels Van Hoef <niels vanhoef gmail com> wrote:
>
>  I tried you suggestion even before posting this question but a small
>  test program yields the following results:
>
>  <?xml version="1.0" encoding="UTF-8"?>
>  <site xmlns:="default">
>   <node>element</node>
>  </site>

This looks like you've passed a pointer to an empty string, rather
than a null pointer.

>  Where as I would suspect:
>
>  <?xml version="1.0" encoding="UTF-8"?>
>  <site xmlns="default">
>   <node>element</node>
>  </site>
>
>  I'm rather new to XML but I believe the proper declaration of the
>  default name space should be without the double-colon, right?

Right, the first is not correct by the namespaces spec. Perhaps
libxml2 could be a little more polite by refusing to construct
namespaces that will lead to bad output.

I've written a short example (see simple.c attached) and the output it
should produce (see result.txt attached),

Martin

#include "libxml/parser.h"
#include "libxml/xmlsave.h"

xmlDocPtr simple_create(xmlChar* localname, xmlChar* prefix, xmlChar* ns)
{
	xmlDocPtr doc = xmlNewDoc(0);
	if (doc && localname)
	{
		xmlNodePtr rootnode = xmlNewChild((xmlNodePtr)doc, 0, localname, 0);
		if (rootnode && ns)
		{
			xmlNsPtr nsnode = xmlNewNs(rootnode, ns, prefix);
			if (nsnode)
			{
				xmlSetNs(rootnode, nsnode);	
			}
		}
	}
	return doc;
}

void simple_test(char* localname, char* prefix, char* ns)
{
	xmlDocPtr doc = simple_create((xmlChar*)localname, (xmlChar*)prefix, (xmlChar*)ns);
	if (doc)
	{
		xmlSaveCtxtPtr savectxt = xmlSaveToFd(1, 0, XML_SAVE_NO_DECL);
		if (savectxt)
		{
			xmlSaveDoc(savectxt, doc);
			xmlSaveClose(savectxt);
		}
		xmlFreeDoc(doc);
	}
}

int main()
{
	/* With prefix, fine */
	simple_test("root", "xmp", "http://example.com/ns";);
	
	/* No prefix, fine */
	simple_test("root", 0, "http://example.com/ns";);
	
	/* Empty prefix, bad! */
	simple_test("root", "", "http://example.com/ns";);
	
	return 0;
}

<xmp:root xmlns:xmp="http://example.com/ns"/>
<root xmlns="http://example.com/ns"/>
<:root xmlns:="http://example.com/ns"/>