类似于libxml2中selectSingleNode的功能？

Question

<?xml version="1.0"?>
<catalog>
   <book id="bk101">
      <author>Gambardella, Matthew</author>
      <title>XML Developer's Guide</title>
      <genre>Computer</genre>
      <price>44.95</price>
      <publish_date>2000-10-01</publish_date>
      <description>An in-depth look at creating applications 
      with XML.</description>
   </book>
   <book id="bk102">
      <author>Ralls, Kim</author>
      <title>Midnight Rain</title>
      <genre>Fantasy</genre>
      <price>5.95</price>
      <publish_date>2000-12-16</publish_date>
      <description>A former architect battles corporate zombies, 
      an evil sorceress, and her own childhood to become queen 
      of the world.</description>
   </book>
<catalog>

IXMLDOMNode* pnode;
IXMLDOMNode* pNodeAuthor = NULL;
pnode->selectSingleNode (CComBSTR(L"author"), & pNodeAuthor);

OR

getElementsByTagName("book[@id='bk101']") 

OR

selectNodes("//book[@id='bk101']") 

Q: In the above XML file, using Microsoft's XML DOM I am able to get any specific node by using selectSingleNode() or getElementbyTagName() or selectNodes() function, just by passing the node name.

I want to do the same using Libxml2, I've read all the standard functions, but not getting any function like that, if you know any function similar or the other way to do that then Please Help!

Answer 1

It's a lot of time I don't use libxml2 but...

There are more ways to do it. One way is using xpath

Here it's an example

Briefly, first of all you should open and parse the xml file, obtaining an xmlDocPtr with xmlParseFile()

xmlDocPtr xmlDoc = xmlParseFile(fileName);

Next, you should create an xml-path context with xmlXPathNewContext()

xmlXPathContextPtr  xPathCnt = xmlXPathNewContext(xmlDoc);

Now you can find nodes with xpath rules; in your case

xmlXPathObjectPtr result = xmlXPathEvalExpression((xmlChar*)"//book[@id=\'bk101\']", xPathCnt);

If the result isn't empy, and you can check this with

xmlXPathNodeSetIsEmpty(result->nodesetval)

your elements should be in result->nodessetval and they number should be result->nodessetval->nodeNr

More details in the linked example.

ps: caution, code not tested

ps2: sorry for my bad English