I'm reading some XML into a XmlDocument using the following code:
if (window.DOMParser)
{
oParser = new DOMParser();
oXml = oParser.parseFromString(this._code, "text/xml");
}
else // Internet Explorer
{
oXml = new ActiveXObject("Microsoft.XMLDOM");
oXml.async = false;
oXml.loadXML(this._code);
}
The test XML looks like this:
<Macro>
<StepCount>1</StepCount>
<Step0>
<StepType>CLOSEFORM</StepType>
<Description>Close Form</Description>
<OnSuccess>NEXTSTEP</OnSuccess>
<OnFailure>SHOWERRORSANDSTOP</OnFailure>
<CheckWithUser>False</CheckWithUser>
<UserOptions>
<Description>
Are you sure you want to close the form?
</Description>
</UserOptions>
</Step0>
</Macro>
The XML has been designed so that each node within it has a unique path (hence the tag Step0 rather than just Step). I'm aware that XML doesn't conform to this restriction normally. I'm trying to use oXml.getElementsByTagName, which should return an array of nodes that match the tag name.
I'd like to be able to obtain the value of at a specific path, for example: /Macro/Step0/Description".
However, if I use getElementsByTagName, I can only specify "Description" as the tag name, which will return me two nodes, one I want and one from deeper in the XML. If there are multiple Steps (Step1, Step2 etc), I will also get multiple Descriptions back that I'm uninterested in.
Is there another method where I can specify the path to the node? I don't mind getting an array back, as in this case, the array will only ever contain one element, given the restriction indicated. I'm aware of document.evaluate, but that only applies to the HTML document.
Alternatively, if I have an element that I've obtained using getElementsByTagName how do I get it's full path?
Well, I've derived an solution, but there may be a better way (I hope so). The approach I've used is to get all nodes that match the last tag of the path using getElementsByTagName. The run through those deriving the full path, and returning the first item that matches the full path. Not elegant, and I certainly wouldn't use it on a large dataset, but it works for the volume of data I'm looking at.
The code is:
function XmlDeriveFullPath(element) // returns the full path to the element within the XML, assuming that each node has a unique path
{
var cPath = "/" + element.tagName;
while ((element.parentNode != null) && (element.parentNode != undefined))
{
element = element.parentNode;
if (element.tagName != null)
cPath = "/" + element.tagName + cPath;
}
return cPath;
}
function XmlGetValueStr(oXml, cPath, cDefault = "") // Returns the value of the first node matching path. On error or no node, returns cDefault
{
var aPath;
var cLastTag;
var i;
var cFullPath;
try
{
// get the last tag in the path
aPath = cPath.split("/");
cLastTag = aPath[aPath.length - 1];
var elements = oXml.getElementsByTagName(cLastTag); // gives us a list of items with the same tag
for (i=0; i<elements.length; i++)
{
cFullPath = XmlDeriveFullPath(elements[i]);
if (cFullPath == cPath)
{
return elements[i].firstChild.nodeValue;
}
}
return cDefault;
}
catch (e)
{
console.log("#XmlGetNodeStr: " + e);
throw e;
}
}
function XmlGetValueInt(oXml, cPath, iDefault = 0) // Returns the value of the first node matching path
{
var cValue;
var iValue;
try
{
cValue = XmlGetNodeStr(oXml, cPath, "");
iValue = parseInt(cValue);
return iValue;
}
catch (e)
{
console.log("#XmlGetNodeInt: " + e);
return iDefault;
}
}
iStepCount = XmlGetValueInt(oXml, "/Macro/StepCount", 0);
If someone does have a better solution, please post.