Xml – How to delete a specific node within a XML file by using vbscript

vbscriptxmlxpath

I am having the problem that I cannot select a specific XML node which needs to be deleted. I have already tried to select the node by using the XPath which works fine for some XML files but I cannot figure out the correct XPath for a node in a more complex file.

Does anybody know a freeware tool which can load a XML file so that the user can select a specific node and receives the accurate XPath without having an enumeration in the path?

/root/anything[2] <– unfortunatly I cannot use such a statement because the number of the element might change. I need an expression that is based on an attribute.

In case that there is no freeware tool for this operation, does anybody know another way how I can select the needed node?

XML Sample:

Root Node: SmsFormData

Attributes: xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" FormatVersion="1.0" xmlns="http://schemas.microsoft.com/SystemsManagementServer/2005/03/ConsoleFramework"

Child node: Form

Attributes: Id="some GUID" CustomData="Some data" FormType="some type" ForceRefresh="false"

Child/Child node: Pages

Child/Child/Child node: Page

Attributes: VendorId="VendorName" Id="some GUID" Assembly="dll File name" Namespace="some Namespace" Type="some Type" HelpID="">

My xPath expression to select this specific page would now be:

xPath = /SmsFormData/Form/Pages/Page[@Id="some Guid"]

To do the selection I am using the following vbscript code:

Set objDOM = CreateObject("Msxml2.DOMDocument.4.0") 
objDOM.async = false            
objDOM.load(file)       
set objNode = objDOM.selectSingleNode(xPath)

The problem is now that the objNode object is empty. The node is not selected, but why?

Best Answer

This is a default namespace issue. Try including the following code after you load in the XML:

objDom.SetProperty "SelectionNamespaces", "xmlns:cf=""http://schemas.microsoft.com/SystemsManagementServer/2005/03/ConsoleFramework"""

You then use this cf prefix in your XPath eg:

objDom.SelectSingleNode("/cf:SmsFormData/cf:Form/cf:Pages/cf:Page[@Id='Some Guid']")

Whilst this may seem a bit quirky, it is intentional behaviour. Take a look at http://support.microsoft.com/kb/288147 for more information, and you may find http://msdn.microsoft.com/en-us/library/ms950779.aspx useful as well.

Related Solutions

Python – How to parse XML and count instances of a particular node attribute

I suggest ElementTree. There are other compatible implementations of the same API, such as lxml, and cElementTree in the Python standard library itself; but, in this context, what they chiefly add is even more speed -- the ease of programming part depends on the API, which ElementTree defines.

First build an Element instance root from the XML, e.g. with the XML function, or by parsing a file with something like:

import xml.etree.ElementTree as ET
root = ET.parse('thefile.xml').getroot()

Or any of the many other ways shown at ElementTree. Then do something like:

for type_tag in root.findall('bar/type'):
    value = type_tag.get('foobar')
    print(value)

And similar, usually pretty simple, code patterns.

Java – How to read XML using XPath in Java

You need something along the lines of this:

DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
DocumentBuilder builder = factory.newDocumentBuilder();
Document doc = builder.parse(<uri_as_string>);
XPathFactory xPathfactory = XPathFactory.newInstance();
XPath xpath = xPathfactory.newXPath();
XPathExpression expr = xpath.compile(<xpath_expression>);

Then you call expr.evaluate() passing in the document defined in that code and the return type you are expecting, and cast the result to the object type of the result.

If you need help with a specific XPath expressions, you should probably ask it as separate questions (unless that was your question in the first place here - I understood your question to be how to use the API in Java).

Edit: (Response to comment): This XPath expression will get you the text of the first URL element under PowerBuilder:

/howto/topic[@name='PowerBuilder']/url/text()

This will get you the second:

/howto/topic[@name='PowerBuilder']/url[2]/text()

You get that with this code:

expr.evaluate(doc, XPathConstants.STRING);

If you don't know how many URLs are in a given node, then you should rather do something like this:

XPathExpression expr = xpath.compile("/howto/topic[@name='PowerBuilder']/url");
NodeList nl = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);

And then loop over the NodeList.

Best Answer

Related Solutions

Python – How to parse XML and count instances of a particular node attribute

Java – How to read XML using XPath in Java

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