int xcaps_xpath_get(str *inbuf, str *xpaths, str *outbuf)
{
	xmlDocPtr doc = NULL;
	xmlXPathContextPtr xpathCtx = NULL; 
	xmlXPathObjectPtr xpathObj = NULL; 
	xmlNodeSetPtr nodes;
	xmlChar *keyword;
	xmlBufferPtr psBuf;
	int size;
	int i;
	char *p;
	char *end;
	char *pos;

	doc = xmlParseMemory(inbuf->s, inbuf->len);
	if(doc == NULL)
		return -1;

	xpathCtx = xmlXPathNewContext(doc);
	if(xpathCtx == NULL)
	{
		LM_ERR("unable to create new XPath context\n");
		goto error;
	}
	
	/* Evaluate xpath expression */
	// xcaps_xpath_register_ns(xpathCtx);
	xpathObj = xmlXPathEvalExpression(
					(const xmlChar*)xpaths->s, xpathCtx);
	if(xpathObj == NULL)
	{
		LM_ERR("unable to evaluate xpath expression [%s]\n", xpaths->s);
		goto error;
	}
    nodes = xpathObj->nodesetval;
	if(nodes==NULL)
	{
		outbuf->len = 0;
		outbuf->s[outbuf->len] = '\0';
		goto done;
	}
	size = nodes->nodeNr;
    p = outbuf->s;
	end = outbuf->s + outbuf->len;
	for(i = 0; i < size; ++i)
	{
		if(nodes->nodeTab[i]==NULL)
			continue;
		if(i!=0)
		{
			if(p>=end)
			{
				LM_ERR("output buffer overflow\n");
				goto error;
			}
			*p = ',';
			p++;
		}
		if(nodes->nodeTab[i]->type == XML_ATTRIBUTE_NODE)
		{
			keyword = xmlNodeListGetString(doc,
				nodes->nodeTab[i]->children, 0);
			if(keyword != NULL)
			{
				pos = p + strlen((char*)keyword);
				if(pos>=end)
				{
					LM_ERR("output buffer overflow\n");
					goto error;
				}
				strcpy(p, (char*)keyword);
				p = pos;
				xmlFree(keyword);
				keyword = NULL;
			}
		} else {
			if(nodes->nodeTab[i]->content!=NULL)
			{
				pos = p + strlen((char*)nodes->nodeTab[i]->content);
				if(pos>=end)
				{
					LM_ERR("output buffer overflow\n");
					goto error;
				}
				strcpy(p, (char*)nodes->nodeTab[i]->content);
				p = pos;
			} else {
				psBuf = xmlBufferCreate();
				if(psBuf != NULL && xmlNodeDump(psBuf, doc,
						nodes->nodeTab[i], 0, 0)>0)
				{
					pos = p + strlen((char*)xmlBufferContent(psBuf));
					if(pos>=end)
					{
						LM_ERR("output buffer overflow\n");
						goto error;
					}
					strcpy(p, (char*)xmlBufferContent(psBuf));
					p = pos;
				}
				if(psBuf != NULL) xmlBufferFree(psBuf);
				psBuf = NULL;
			}
		}
	}
	outbuf->len = p - outbuf->s;
	outbuf->s[outbuf->len] = '\0';

done:
	if(xpathObj!=NULL) xmlXPathFreeObject(xpathObj);
	if(xpathCtx!=NULL) xmlXPathFreeContext(xpathCtx); 
	if(doc!=NULL) xmlFreeDoc(doc);
	xpathObj = NULL;
	xpathCtx = NULL; 
	doc = NULL; 
	return 0;

error:
	if(xpathObj!=NULL) xmlXPathFreeObject(xpathObj);
	if(xpathCtx!=NULL) xmlXPathFreeContext(xpathCtx); 
	if(doc!=NULL) xmlFreeDoc(doc);
	xpathObj = NULL;
	xpathCtx = NULL; 
	doc = NULL; 
	outbuf->len = 0;
	outbuf->s[outbuf->len] = '\0';
	return -1;
}