Question

I'm curently porting a C++ project from libxml2 to pugixml. I have an XPath query that used to work perfectly well with libxml2 but returns zero nodes with pugixml:

"//*[local-name(.) = '" + name + "']"

where name is the name of the elements I want to retrieve. Can anyone shed any light on what's happening?

Code:

const string path = "//*[local-name(.) = '" + name + "']";
std::cerr << path << std::endl;
try {
   const xpath_node_set nodes = this->doc.select_nodes(path.c_str());
   return nodes;
} catch(const xpath_exception& e) {
   std::cerr << e.what() << std::endl;
   throw logic_error("Could not select elements from document.");
}

Name: "Page"

XML:

<MyDocument>
  <Pages>
    <Page>
      <Para>
        <Word>Some</Word>
        <Word>People</Word>
      </Para>
    </Page>
    <Page>
      <Para>
        <Word>Some</Word>
        <Word>Other</Word>
        <Word>People</Word>
      </Para>
    </Page>
  </Pages>
</MyDocument>
Was it helpful?

Solution

This program works for me. Are you using the latest version of pugixml?

Alternatively I did notice that pugixml isn't good with namespaces, you may need to specify them in the node name you are searching for.

I just checked and it works fine with namespaces.

#include <pugixml.hpp>

#include <iostream>

const char* xml =
"<MyDocument>"
"  <Pages>"
"    <Page>"
"      <Para>"
"        <Word>Some</Word>"
"        <Word>People</Word>"
"      </Para>"
"    </Page>"
"    <Page>"
"      <Para>"
"        <Word>Some</Word>"
"        <Word>Other</Word>"
"        <Word>People</Word>"
"      </Para>"
"    </Page>"
"  </Pages>"
"</MyDocument>";

int main()
{
    std::string name = "Para";

    const std::string path = "//*[local-name(.) = '" + name + "']";

    pugi::xml_parse_result result;

    pugi::xml_document doc;

    doc.load(xml);

    const pugi::xpath_node_set nodes = doc.select_nodes(path.c_str());

    for(auto& node: nodes)
    {
        std::cout << node.node().name() << '\n';
    }
}

OUTPUT

Para
Para
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