local-name() not working in XPath

Question

My XML is like below:

<?xml version="1.0"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
                             http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <mime-mapping>
        <extension>123</extension>
        <mime-type>application/vnd.lotus-1-2-3</mime-type>
    </mime-mapping>
    <mime-mapping>
        <extension>3dml</extension>
        <mime-type>text/vnd.in3d.3dml</mime-type>
    </mime-mapping>
</web-app>

As you see, it has namespace so default xpath such as /web-app/mime-mapping/mime-type will not work.

Based on my reading on various threads, I tried:

/*[local-name()='web-app']/*[local-name()='mime-mapping']/*[local-name()='mime-type']

AND

/*[name()='web-app']/*[name()='mime-mapping']/*[name()='mime-type']

AND

/*[name()='web-app' and namespace-uri()='http://java.sun.com/xml/ns/javaee']/*[name()='mime-mapping' and namespace-uri()='http://java.sun.com/xml/ns/javaee']/*[name()='mime-type' and namespace-uri()='http://java.sun.com/xml/ns/javaee']

But none seem to work. I am testing in http://www.freeformatter.com/xpath-tester.html. Also, I am testing in my tool which requires XPath 1.0 and it does not recognize any of the above either.

Any pointers?

Try a different tester. http://www.xpathtester.com/xpath finds matches. — Alohci, Jul 03 '16 at 00:00
But, the tool that I use requires xpath 1.0. Is the specified xpath a 1.0? That tool does not match this xpath either. Can we handle this in any other manner? — praving5, Jul 03 '16 at 01:14
@Alohci - I tried in the tool you suggested. But, it does not match any of the three either? It gives below error: `ERROR - Seem there is no XPath provided?` — praving5, Jul 03 '16 at 03:04
@praving5: That error indicates that you probably put the XPath in the wrong input field on that page. — kjhughes, Jul 03 '16 at 16:19

score 2 · Accepted Answer · edited May 23 '17 at 11:58

2

Your XPath is fine.

It is your tool (http://www.freeformatter.com/xpath-tester.html) that is the problem.

Do not use http://www.freeformatter.com/xpath-tester.html with XML that has a default namespace. It is noncompliant. You can see this in the error message that they post for your XML:

The default (no prefix) Namespace URI for XPath queries is always '' and it cannot be redefined to 'http://java.sun.com/xml/ns/javaee'.

Compliant XPath processors will return

<mime-type xmlns="http://java.sun.com/xml/ns/javaee">application/vnd.lotus-1-2-3</mime-type>
<mime-type xmlns="http://java.sun.com/xml/ns/javaee">text/vnd.in3d.3dml</mime-type>

for your XPath, as expected.

Alternatively, and preferably, follow best practices and define a namespace prefix for the default namespace:

j="http://java.sun.com/xml/ns/javaee"

and use it in the XPath rather than local-name():

/j:web-app/j:mime-mapping/j:mime-type

to get the same result properly without skirting namespaces.

Unfortunately, you cannot define a namespace prefix on the Freeformatter site, but you can on http://www.xpathtester.com/xpath as well as with most XPath libraries.

edited May 23 '17 at 11:58

Community

1
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answered Jul 03 '16 at 02:00

kjhughes

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The message that they post is not incorrect. But it is irrelevant when using an xpath like `/*[local-name()='web-app']/*[local-name()='mime-mapping']/*[local-name()='mime-type']` – Alohci Jul 03 '16 at 02:03
@Alohci: The message that they post expresses an important and unfortunate limitation that is relevant to OP's situation. It is also unfortunate that the site provides no way to defined a namespace prefix so that the XPath can be written properly without resorting to `local-name()`. – kjhughes Jul 03 '16 at 02:09
@Alohci: The alternative that you posted in your comment, http://www.xpathtester.com/xpath, does not suffer from the same problem. And http://www.online-toolz.com/tools/xpath-editor.php will at least work with the `local-name()`-based XPath, as will most others I've come across. – kjhughes Jul 03 '16 at 02:16
Thanks. That is tcserver xml file (web.xml) and I have no control over it as such. I will try what's wrong in my tool. May be it has similar problem like the tester tool. – praving5 Jul 03 '16 at 03:01
Got it. On SLES 11 SP3, we have xpath utility. That does not seem to support namespace-uri. `# xpath /usr/lib/vmware-vcops/tomcat-web-app/conf/web.xml "/*[name()='web-app' and namespace-uri()='http://java.sun.com/xml/ns/javaee']/*[name()='mime-mapping' and namespace-uri()='http://java.sun.com/xml/ns/javaee']/*[name()='mime-type' and namespace-uri()='http://java.sun.com/xml/ns/javaee']" namespace-uri: Function not supported` – praving5 Jul 03 '16 at 03:16
Then I removed, namespace-uri and gave the xpath within "". And it worked perfectly. Thanks a lot. I was missing "" and it was breaking the xpath processor. Seems weird. – praving5 Jul 03 '16 at 03:17
Your XML is fine too. **[namespace-uri()](https://www.w3.org/TR/xpath/#function-namespace-uri)** is part of XPath 1.0 and should be supported. You're having bad luck with tools today. – kjhughes Jul 03 '16 at 03:28

local-name() not working in XPath

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