iPhone SDK: XML mystery, after adding child nodeforXPath returns nothing (found a hacky solution)

Question

I have a big mystery here,

I have a Gdataxml document property:

GDataXMLDocument *doc;

I\'m adding a new element to doc, interestin

Answer 1

Your problem is here:

<inferenceresponse xmlns="">

The empty namespace attribute is obviously confusing the libxml XPath evaluation. If you step through GDataXMLNode's nodesForXPath:namespaces:error:, xmlXPathEval indeed returns an empty nodes set.

If you have control over the XML generation, I've got correct XPath results removing the empty attribute.

<inferenceresponse>

If modifying the server response is too hard, you can edit GDataXMLNode.m: Find the method fixQualifiedNamesForNode:graftingToTreeNode: in GDataXMLNode implementation and replace the line

if (foundNS != NULL) {
    // we found a namespace, so fix the ns pointer and the local name

with

if (foundNS != NULL && foundNS->href != NULL && strlen((char *)foundNS->href) != 0) {
    // we found a namespace, so fix the ns pointer and the local name