XPath - selecting node based on following sibling - xpath

Question

I have a query like this:
/plist/dict[1]/dict/dict/dict/key/following-sibling::dict/string[string()='Algier']
What I really want to select is the 'key' node (just before the following-sibling::dict) one.
The xml is like this :
<?xml version="1.0" encoding="UTF-8"?>
<plist version="1.0">
<dict>
<key>en_GB</key>
<dict>
<key>Africa</key>
<dict>
<key>Algeria</key>
<dict>
<key>60390</key>
<dict>
<key>NAME</key>
<string>Algier</string>
<key>LATITUDE</key>
<string>36.7500</string>
<key>LONGITUDE</key>
<string>3.0500</string>
</dict>
<key>60391</key>
<dict>
<key>NAME</key>
<string>Some other city</string>
<key>LATITUDE</key>
<string>36.7500</string>
<key>LONGITUDE</key>
<string>3.0500</string>
</dict>
</dict>
</dict>
</dict>
</dict>
</plist>
In other words, I want to select '60390' when the city name is 'Algier' or (60391 when city name is 'some other city').
I'm doing this in a QML XmlListModel.
Updated code
QML used:
import QtQuick 1.0
Rectangle {
id: container;
width: 360
height: 360
function onLocationModelLoaded(){
console.debug(weLocationModel.count);
}
XmlListModel{
id: weLocationModel;
source: "we_locations.plist";
query: "/*/dict/dict/dict/dict/key[following-sibling::dict[1]/key[.='NAME' and following-sibling::string[1] = 'Algier']]"
XmlRole{
name: "cityId";
query: "name()";
}
onStatusChanged: {
if (status == XmlListModel.Ready){
console.debug("Location Model Ready");
container.onLocationModelLoaded();
}
}
}
}
It seems like the nested following-sibling is not working.
for example something like:
query: "/*/dict/dict/dict/dict/key[following-sibling::dict[1]/key[.='NAME']]"
Both of these always return:
Error XPST0003 in file:///Users/Ali/qtprojects/welocationtest-build-simulator/welocationtest.app/Contents/MacOS/welocationtest, at line 2, column 97: syntax error, unexpected ], expecting )
Error XPST0003 in file:///Users/Ali/qtprojects/welocationtest-build-simulator/welocationtest.app/Contents/MacOS/welocationtest, at line 2, column 91: syntax error, unexpected ], expecting end of file
file:///Users/Ali/qtprojects/welocationtest-build-simulator/welocationtest.app/Contents/Resources/qml/welocationtest/main.qml:17:9: QML XmlRole: invalid query: "name()"
Location Model Ready
0
Could it be possible QML is not following XPath standard? THe solution works in all other path editors.

Answer 1

One XPath expression that selects exactly the wanted key element is this:
/*/dict/dict/dict/dict
/key
[following-sibling::dict[1]/key
[.='NAME'
and
following-sibling::string[1] = $pCity
]
]
When $pCity is set/substituted-by "Algier", this XPath expression selects:
<key>60390</key>
When $pCity is set/substituted-by "Some other city", this XPath expression selects:
<key>60391</key>
XSLT-based verification:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
<xsl:output omit-xml-declaration="yes" indent="yes"/>
<xsl:param name="pCity" select="'Some other city'"/>
<xsl:template match="/">
<xsl:copy-of select=
"/*/dict/dict/dict/dict
/key
[following-sibling::dict[1]/key
[.='NAME'
and
following-sibling::string[1] = $pCity
]
]
"/>
</xsl:template>
</xsl:stylesheet>
When this transformation is applied against the provided XML document:
<plist version="1.0">
<dict>
<key>en_GB</key>
<dict>
<key>Africa</key>
<dict>
<key>Algeria</key>
<dict>
<key>60390</key>
<dict>
<key>NAME</key>
<string>Algier</string>
<key>LATITUDE</key>
<string>36.7500</string>
<key>LONGITUDE</key>
<string>3.0500</string>
</dict>
<key>60391</key>
<dict>
<key>NAME</key>
<string>Some other city</string>
<key>LATITUDE</key>
<string>36.7500</string>
<key>LONGITUDE</key>
<string>3.0500</string>
</dict>
</dict>
</dict>
</dict>
</dict>
</plist>
the wanted, correct result is produced:
<key>60391</key>
When in the above transformation we replace:
<xsl:param name="pCity" select="'Some other city'"/>
with:
<xsl:param name="pCity" select="'Algier'"/>
and apply the transformation again, then again we get the correct result:
<key>60390</key>

Answer 2

To get the number for a city you can use a RegEx, too (especially if QML XPath support is not good enough):
import QtQuick 1.0
Rectangle {
id: container
width: 360
height: 360
Component.onCompleted: {
loadWeLocationsFile();
}
property string weLocationsXML
signal weLocationsLoaded()
function loadWeLocationsFile() {
// load file
var doc = new XMLHttpRequest();
doc.onreadystatechange = function() {
if (doc.readyState == XMLHttpRequest.DONE) {
// get file content
weLocationsXML = doc.responseText;
// emit signal
weLocationsLoaded();
}
}
doc.open("GET", "we_locations.plist");
doc.send();
}
function getIDByName(name) {
// escape special characters for regex (maybe there is a better way to do this)
var safeName = name.replace(/[-.,?+*#^$()[\]{}\\|]/g, "\\$&");
// create regex
var regex = new RegExp("<key>(.*?)</key>\\s*<dict>\\s*<key>NAME</key>\\s*<string>" + safeName + "</string>", "m");
// execute regex
var match = regex.exec(weLocationsXML);
if (match != null && match.length > 1) {
return match[1]; // name found, group 1 contains id
} else {
return null; // no such name in XML
}
}
// Test it ...
onWeLocationsLoaded: {
console.log("Number for 'Algier':", getIDByName("Algier"));
console.log("Number for 'NotInXML':", getIDByName("NotInXML"));
console.log("Number for 'Some other city':", getIDByName("Some other city"));
}
}
Output:
Number for 'Algier': 60390
Number for 'NotInXML': null
Number for 'Some other city': 60391
If you need the number in a QML model you can create a ListModel and add the number to it.