After researching on google I have not find a working solution for this.
The 'MAVEN by Example' ebook uses the Yahoo weather example. Unfortunately it looks like Yahoo changed their interface. I tried to adapt the java code for this, but get this annoying exception:
exec-maven-plugin:1.5.0:java
Failed to execute goal org.codehaus.mojo:exec-maven-plugin:1.5.0:java
Caused by: org.dom4j.XPathException:
Exception occurred evaluting XPath: /query/results/channel/yweather:location/#city.
Exception: XPath expression uses unbound namespace prefix yweather
The xml line itself is:
<query xmlns:yahoo="http://www.yahooapis.com/v1/base.rng" yahoo:count="1" yahoo:created="2017-02-13T10:57:34Z" yahoo:lang="en-US">
<results>
<channel>
...
<yweather:location xmlns:yweather="http://xml.weather.yahoo.com/ns/rss/1.0" city="Theale" country="United Kingdom" region=" England"/>
The entire XML can be generated from :
https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20weather.forecast%20where%20woeid%3D91731537
My code (as per the 'MAVEN By Example' ebook, xpath and url modified for the changed Yahoo):
public Weather parse(InputStream inputStream) throws Exception {
Weather weather = new Weather();
SAXReader xmlReader = createXmlReader();
Document doc = xmlReader.read( inputStream );
weather.setCity(doc.valueOf ("//yweather:location/#city") );
// and several more, such as setCountry, setTemp
}
(I'm not an xpath expert, so I tried
/query/results/channel/item/yweather:location/#city
as well, just in case, with the same result.
xmlReader:
public InputStream retrieve(String woeid) throws Exception {
String url = "https://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20weather.forecast%20where%20woeid%3D"+woeid; // eg 91731537
URLConnection conn = new URL(url).openConnection();
return conn.getInputStream();
}
and the weather class is just a set of getters and setters
When I try this in this XML tester, it works just fine, but that may be the effect of XPATH-v2 vs Java's v1.
When you evaluate your XPath //yweather:location/#city, the XPath processor has no knowledge of which namespace the yweather prefix is bound to. You'll need to provide that information. Now, you might think "the info is right there in the document!" and you'd be right. But prefixes are just a sort of stand-in (like a variable) for the actual namespace. A namespace can be bound to any prefix you like that follows the prefix naming rules, and can be bound to multiple prefixes as well. Just like the variable name in Java referring to an object is of itself of no importance, and multiple variables could refer to the same object.
For example, if you used XPath //yw:location/#city with the prefix yw bound to namespace http://xml.weather.yahoo.com/ns/rss/1.0, it'd still work the same.
I suggest you use class org.dom4j.xpath.DefaultXPath instead of calling valueOf. Create an instance of it and initialize the namespace context. There's a method setNamespaceURIs that takes a Map from prefixes to namespaces and lets you make the bindings. Bind the above weather namespace (the actual URI) to some prefix of your choosing (may be yweather, but can be anything else you want to use in your actual XPath expression) and then use the instance to evaluate it over the document.
Here's an answer I gave to some question that goes more in-depth about what namespaces and their prefixes really are: https://stackoverflow.com/a/8231272/630136
EDIT: the online XPath tester you used probably does some behind-the-scenes magic to extract the namespaces and their prefixes from the given document and bind those in the XPath processor.
If you look at their sample XML and adjust it like this...
<root xmlns:foo="http://www.foo.org/" xmlns:bar="http://www.bar.org">
<actors>
<actor id="1">Christian Bale</actor>
<actor id="2">Liam Neeson</actor>
<actor id="3">Michael Caine</actor>
</actors>
<foo:singers xmlns:test="http://www.foo.org/">
<test:singer id="4">Tom Waits</test:singer>
<foo:singer id="5">B.B. King</foo:singer>
<foo:singer id="6">Ray Charles</foo:singer>
</foo:singers>
</root>
the XML is semantically equivalent, because the test prefix is bound to the same namespace as foo. The XPath //foo:singer/#id still returns all the right results, so the tool is smart about it. However, it doesn't know what to do with XML...
<root xmlns:foo="http://www.foo.org/" xmlns:bar="http://www.bar.org">
<actors>
<foo:actor id="1">Christian Bale</foo:actor>
<actor id="2">Liam Neeson</actor>
<actor id="3">Michael Caine</actor>
</actors>
<foo:singers xmlns:test="http://www.foo.org/" xmlns:foo="http://www.bar.org">
<test:singer id="4">Tom Waits</test:singer>
<foo:singer id="5">B.B. King</foo:singer>
<foo:singer id="6">Ray Charles</foo:singer>
</foo:singers>
</root>
and XPath //foo:*/#id. The prefix foo is bound to a different namespace in the singers element scope, and now it only returns the ids 5 and 6. Contrast it with this XPath, that doesn't use a prefix but the namespace-uri() function: //*[namespace-uri()='http://www.foo.org/']/#id
That last one returns ids 1 and 4, as expected.
I found the error, it's my unfamiliarity with namespaces. The 'createXmlReader()'
used in my example above is a method that sets the correct namespace, except that I forgot to change it after Yahoo changed the xml. Careful re-reading the Maven-by-example documentation, the generated error, and comparing with the detailed answer given here, it suddenly clicked. The updated code (for the benefit of anyone trying the same example):
private SAXReader createXmlReader() {
Map<String,String> uris = new HashMap<String,String>();
uris.put( "yweather", "http://xml.weather.yahoo.com/ns/rss/1.0" );
DocumentFactory factory = new DocumentFactory();
factory.setXPathNamespaceURIs( uris );
SAXReader xmlReader = new SAXReader();
xmlReader.setDocumentFactory( factory );
return xmlReader;
}
The only change is in the line 'uris.put()'
Originally the namespace was "y", now it is "yweather".
Related
How does XPath deal with XML namespaces?
If I use
/IntuitResponse/QueryResponse/Bill/Id
to parse the XML document below I get 0 nodes back.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<IntuitResponse xmlns="http://schema.intuit.com/finance/v3"
time="2016-10-14T10:48:39.109-07:00">
<QueryResponse startPosition="1" maxResults="79" totalCount="79">
<Bill domain="QBO" sparse="false">
<Id>=1</Id>
</Bill>
</QueryResponse>
</IntuitResponse>
However, I'm not specifying the namespace in the XPath (i.e. http://schema.intuit.com/finance/v3 is not a prefix of each token of the path). How can XPath know which Id I want if I don't tell it explicitly? I suppose in this case (since there is only one namespace) XPath could get away with ignoring the xmlns entirely. But if there are multiple namespaces, things could get ugly.
XPath 1.0/2.0
Defining namespaces in XPath (recommended)
XPath itself doesn't have a way to bind a namespace prefix with a namespace. Such facilities are provided by the hosting library.
It is recommended that you use those facilities and define namespace prefixes that can then be used to qualify XML element and attribute names as necessary.
Here are some of the various mechanisms which XPath hosts provide for specifying namespace prefix bindings to namespace URIs.
(OP's original XPath, /IntuitResponse/QueryResponse/Bill/Id, has been elided to /IntuitResponse/QueryResponse.)
C#:
XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace("i", "http://schema.intuit.com/finance/v3");
XmlNodeList nodes = el.SelectNodes(#"/i:IntuitResponse/i:QueryResponse", nsmgr);
Google Docs:
Unfortunately, IMPORTXML() does not provide a namespace prefix binding mechanism. See next section, Defeating namespaces in XPath, for how to use local-name() as a work-around.
Java (SAX):
NamespaceSupport support = new NamespaceSupport();
support.pushContext();
support.declarePrefix("i", "http://schema.intuit.com/finance/v3");
Java (XPath):
xpath.setNamespaceContext(new NamespaceContext() {
public String getNamespaceURI(String prefix) {
switch (prefix) {
case "i": return "http://schema.intuit.com/finance/v3";
// ...
}
});
Remember to call
DocumentBuilderFactory.setNamespaceAware(true).
See also:
Java XPath: Queries with default namespace xmlns
JavaScript:
See Implementing a User Defined Namespace Resolver:
function nsResolver(prefix) {
var ns = {
'i' : 'http://schema.intuit.com/finance/v3'
};
return ns[prefix] || null;
}
document.evaluate( '/i:IntuitResponse/i:QueryResponse',
document, nsResolver, XPathResult.ANY_TYPE,
null );
Note that if the default namespace has an associated namespace prefix defined, using the nsResolver() returned by Document.createNSResolver() can obviate the need for a customer nsResolver().
Perl (LibXML):
my $xc = XML::LibXML::XPathContext->new($doc);
$xc->registerNs('i', 'http://schema.intuit.com/finance/v3');
my #nodes = $xc->findnodes('/i:IntuitResponse/i:QueryResponse');
Python (lxml):
from lxml import etree
f = StringIO('<IntuitResponse>...</IntuitResponse>')
doc = etree.parse(f)
r = doc.xpath('/i:IntuitResponse/i:QueryResponse',
namespaces={'i':'http://schema.intuit.com/finance/v3'})
Python (ElementTree):
namespaces = {'i': 'http://schema.intuit.com/finance/v3'}
root.findall('/i:IntuitResponse/i:QueryResponse', namespaces)
Python (Scrapy):
response.selector.register_namespace('i', 'http://schema.intuit.com/finance/v3')
response.xpath('/i:IntuitResponse/i:QueryResponse').getall()
PhP:
Adapted from #Tomalak's answer using DOMDocument:
$result = new DOMDocument();
$result->loadXML($xml);
$xpath = new DOMXpath($result);
$xpath->registerNamespace("i", "http://schema.intuit.com/finance/v3");
$result = $xpath->query("/i:IntuitResponse/i:QueryResponse");
See also #IMSoP's canonical Q/A on PHP SimpleXML namespaces.
Ruby (Nokogiri):
puts doc.xpath('/i:IntuitResponse/i:QueryResponse',
'i' => "http://schema.intuit.com/finance/v3")
Note that Nokogiri supports removal of namespaces,
doc.remove_namespaces!
but see the below warnings discouraging the defeating of XML namespaces.
VBA:
xmlNS = "xmlns:i='http://schema.intuit.com/finance/v3'"
doc.setProperty "SelectionNamespaces", xmlNS
Set queryResponseElement =doc.SelectSingleNode("/i:IntuitResponse/i:QueryResponse")
VB.NET:
xmlDoc = New XmlDocument()
xmlDoc.Load("file.xml")
nsmgr = New XmlNamespaceManager(New XmlNameTable())
nsmgr.AddNamespace("i", "http://schema.intuit.com/finance/v3");
nodes = xmlDoc.DocumentElement.SelectNodes("/i:IntuitResponse/i:QueryResponse",
nsmgr)
SoapUI (doc):
declare namespace i='http://schema.intuit.com/finance/v3';
/i:IntuitResponse/i:QueryResponse
xmlstarlet:
-N i="http://schema.intuit.com/finance/v3"
XSLT:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:i="http://schema.intuit.com/finance/v3">
...
Once you've declared a namespace prefix, your XPath can be written to use it:
/i:IntuitResponse/i:QueryResponse
Defeating namespaces in XPath (not recommended)
An alternative is to write predicates that test against local-name():
/*[local-name()='IntuitResponse']/*[local-name()='QueryResponse']
Or, in XPath 2.0:
/*:IntuitResponse/*:QueryResponse
Skirting namespaces in this manner works but is not recommended because it
Under-specifies the full element/attribute name.
Fails to differentiate between element/attribute names in different
namespaces (the very purpose of namespaces). Note that this concern could be addressed by adding an additional predicate to check the namespace URI explicitly:
/*[ namespace-uri()='http://schema.intuit.com/finance/v3'
and local-name()='IntuitResponse']
/*[ namespace-uri()='http://schema.intuit.com/finance/v3'
and local-name()='QueryResponse']
Thanks to Daniel Haley for the namespace-uri() note.
Is excessively verbose.
XPath 3.0/3.1
Libraries and tools that support modern XPath 3.0/3.1 allow the specification of a namespace URI directly in an XPath expression:
/Q{http://schema.intuit.com/finance/v3}IntuitResponse/Q{http://schema.intuit.com/finance/v3}QueryResponse
While Q{http://schema.intuit.com/finance/v3} is much more verbose than using an XML namespace prefix, it has the advantage of being independent of the namespace prefix binding mechanism of the hosting library. The Q{} notation is known as Clark Notation after its originator, James Clark. The W3C XPath 3.1 EBNF grammar calls it a BracedURILiteral.
Thanks to Michael Kay for the suggestion to cover XPath 3.0/3.1's BracedURILiteral.
I use /*[name()='...'] in a google sheet to fetch some counts from Wikidata. I have a table like this
thes WD prop links items
NOM P7749 3925 3789
AAT P1014 21157 20224
and the formulas in cols links and items are
=IMPORTXML("https://query.wikidata.org/sparql?query=SELECT(COUNT(*)as?c){?item wdt:"&$B14&"[]}","//*[name()='literal']")
=IMPORTXML("https://query.wikidata.org/sparql?query=SELECT(COUNT(distinct?item)as?c){?item wdt:"&$B14&"[]}","//*[name()='literal']")
respectively. The SPARQL query happens not to have any spaces...
I saw name() used instead of local-name() in Xml Namespace breaking my xpath!, and for some reason //*:literal doesn't work.
How does XPath deal with XML namespaces?
If I use
/IntuitResponse/QueryResponse/Bill/Id
to parse the XML document below I get 0 nodes back.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<IntuitResponse xmlns="http://schema.intuit.com/finance/v3"
time="2016-10-14T10:48:39.109-07:00">
<QueryResponse startPosition="1" maxResults="79" totalCount="79">
<Bill domain="QBO" sparse="false">
<Id>=1</Id>
</Bill>
</QueryResponse>
</IntuitResponse>
However, I'm not specifying the namespace in the XPath (i.e. http://schema.intuit.com/finance/v3 is not a prefix of each token of the path). How can XPath know which Id I want if I don't tell it explicitly? I suppose in this case (since there is only one namespace) XPath could get away with ignoring the xmlns entirely. But if there are multiple namespaces, things could get ugly.
XPath 1.0/2.0
Defining namespaces in XPath (recommended)
XPath itself doesn't have a way to bind a namespace prefix with a namespace. Such facilities are provided by the hosting library.
It is recommended that you use those facilities and define namespace prefixes that can then be used to qualify XML element and attribute names as necessary.
Here are some of the various mechanisms which XPath hosts provide for specifying namespace prefix bindings to namespace URIs.
(OP's original XPath, /IntuitResponse/QueryResponse/Bill/Id, has been elided to /IntuitResponse/QueryResponse.)
C#:
XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace("i", "http://schema.intuit.com/finance/v3");
XmlNodeList nodes = el.SelectNodes(#"/i:IntuitResponse/i:QueryResponse", nsmgr);
Google Docs:
Unfortunately, IMPORTXML() does not provide a namespace prefix binding mechanism. See next section, Defeating namespaces in XPath, for how to use local-name() as a work-around.
Java (SAX):
NamespaceSupport support = new NamespaceSupport();
support.pushContext();
support.declarePrefix("i", "http://schema.intuit.com/finance/v3");
Java (XPath):
xpath.setNamespaceContext(new NamespaceContext() {
public String getNamespaceURI(String prefix) {
switch (prefix) {
case "i": return "http://schema.intuit.com/finance/v3";
// ...
}
});
Remember to call
DocumentBuilderFactory.setNamespaceAware(true).
See also:
Java XPath: Queries with default namespace xmlns
JavaScript:
See Implementing a User Defined Namespace Resolver:
function nsResolver(prefix) {
var ns = {
'i' : 'http://schema.intuit.com/finance/v3'
};
return ns[prefix] || null;
}
document.evaluate( '/i:IntuitResponse/i:QueryResponse',
document, nsResolver, XPathResult.ANY_TYPE,
null );
Note that if the default namespace has an associated namespace prefix defined, using the nsResolver() returned by Document.createNSResolver() can obviate the need for a customer nsResolver().
Perl (LibXML):
my $xc = XML::LibXML::XPathContext->new($doc);
$xc->registerNs('i', 'http://schema.intuit.com/finance/v3');
my #nodes = $xc->findnodes('/i:IntuitResponse/i:QueryResponse');
Python (lxml):
from lxml import etree
f = StringIO('<IntuitResponse>...</IntuitResponse>')
doc = etree.parse(f)
r = doc.xpath('/i:IntuitResponse/i:QueryResponse',
namespaces={'i':'http://schema.intuit.com/finance/v3'})
Python (ElementTree):
namespaces = {'i': 'http://schema.intuit.com/finance/v3'}
root.findall('/i:IntuitResponse/i:QueryResponse', namespaces)
Python (Scrapy):
response.selector.register_namespace('i', 'http://schema.intuit.com/finance/v3')
response.xpath('/i:IntuitResponse/i:QueryResponse').getall()
PhP:
Adapted from #Tomalak's answer using DOMDocument:
$result = new DOMDocument();
$result->loadXML($xml);
$xpath = new DOMXpath($result);
$xpath->registerNamespace("i", "http://schema.intuit.com/finance/v3");
$result = $xpath->query("/i:IntuitResponse/i:QueryResponse");
See also #IMSoP's canonical Q/A on PHP SimpleXML namespaces.
Ruby (Nokogiri):
puts doc.xpath('/i:IntuitResponse/i:QueryResponse',
'i' => "http://schema.intuit.com/finance/v3")
Note that Nokogiri supports removal of namespaces,
doc.remove_namespaces!
but see the below warnings discouraging the defeating of XML namespaces.
VBA:
xmlNS = "xmlns:i='http://schema.intuit.com/finance/v3'"
doc.setProperty "SelectionNamespaces", xmlNS
Set queryResponseElement =doc.SelectSingleNode("/i:IntuitResponse/i:QueryResponse")
VB.NET:
xmlDoc = New XmlDocument()
xmlDoc.Load("file.xml")
nsmgr = New XmlNamespaceManager(New XmlNameTable())
nsmgr.AddNamespace("i", "http://schema.intuit.com/finance/v3");
nodes = xmlDoc.DocumentElement.SelectNodes("/i:IntuitResponse/i:QueryResponse",
nsmgr)
SoapUI (doc):
declare namespace i='http://schema.intuit.com/finance/v3';
/i:IntuitResponse/i:QueryResponse
xmlstarlet:
-N i="http://schema.intuit.com/finance/v3"
XSLT:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:i="http://schema.intuit.com/finance/v3">
...
Once you've declared a namespace prefix, your XPath can be written to use it:
/i:IntuitResponse/i:QueryResponse
Defeating namespaces in XPath (not recommended)
An alternative is to write predicates that test against local-name():
/*[local-name()='IntuitResponse']/*[local-name()='QueryResponse']
Or, in XPath 2.0:
/*:IntuitResponse/*:QueryResponse
Skirting namespaces in this manner works but is not recommended because it
Under-specifies the full element/attribute name.
Fails to differentiate between element/attribute names in different
namespaces (the very purpose of namespaces). Note that this concern could be addressed by adding an additional predicate to check the namespace URI explicitly:
/*[ namespace-uri()='http://schema.intuit.com/finance/v3'
and local-name()='IntuitResponse']
/*[ namespace-uri()='http://schema.intuit.com/finance/v3'
and local-name()='QueryResponse']
Thanks to Daniel Haley for the namespace-uri() note.
Is excessively verbose.
XPath 3.0/3.1
Libraries and tools that support modern XPath 3.0/3.1 allow the specification of a namespace URI directly in an XPath expression:
/Q{http://schema.intuit.com/finance/v3}IntuitResponse/Q{http://schema.intuit.com/finance/v3}QueryResponse
While Q{http://schema.intuit.com/finance/v3} is much more verbose than using an XML namespace prefix, it has the advantage of being independent of the namespace prefix binding mechanism of the hosting library. The Q{} notation is known as Clark Notation after its originator, James Clark. The W3C XPath 3.1 EBNF grammar calls it a BracedURILiteral.
Thanks to Michael Kay for the suggestion to cover XPath 3.0/3.1's BracedURILiteral.
I use /*[name()='...'] in a google sheet to fetch some counts from Wikidata. I have a table like this
thes WD prop links items
NOM P7749 3925 3789
AAT P1014 21157 20224
and the formulas in cols links and items are
=IMPORTXML("https://query.wikidata.org/sparql?query=SELECT(COUNT(*)as?c){?item wdt:"&$B14&"[]}","//*[name()='literal']")
=IMPORTXML("https://query.wikidata.org/sparql?query=SELECT(COUNT(distinct?item)as?c){?item wdt:"&$B14&"[]}","//*[name()='literal']")
respectively. The SPARQL query happens not to have any spaces...
I saw name() used instead of local-name() in Xml Namespace breaking my xpath!, and for some reason //*:literal doesn't work.
How does XPath deal with XML namespaces?
If I use
/IntuitResponse/QueryResponse/Bill/Id
to parse the XML document below I get 0 nodes back.
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<IntuitResponse xmlns="http://schema.intuit.com/finance/v3"
time="2016-10-14T10:48:39.109-07:00">
<QueryResponse startPosition="1" maxResults="79" totalCount="79">
<Bill domain="QBO" sparse="false">
<Id>=1</Id>
</Bill>
</QueryResponse>
</IntuitResponse>
However, I'm not specifying the namespace in the XPath (i.e. http://schema.intuit.com/finance/v3 is not a prefix of each token of the path). How can XPath know which Id I want if I don't tell it explicitly? I suppose in this case (since there is only one namespace) XPath could get away with ignoring the xmlns entirely. But if there are multiple namespaces, things could get ugly.
XPath 1.0/2.0
Defining namespaces in XPath (recommended)
XPath itself doesn't have a way to bind a namespace prefix with a namespace. Such facilities are provided by the hosting library.
It is recommended that you use those facilities and define namespace prefixes that can then be used to qualify XML element and attribute names as necessary.
Here are some of the various mechanisms which XPath hosts provide for specifying namespace prefix bindings to namespace URIs.
(OP's original XPath, /IntuitResponse/QueryResponse/Bill/Id, has been elided to /IntuitResponse/QueryResponse.)
C#:
XmlNamespaceManager nsmgr = new XmlNamespaceManager(doc.NameTable);
nsmgr.AddNamespace("i", "http://schema.intuit.com/finance/v3");
XmlNodeList nodes = el.SelectNodes(#"/i:IntuitResponse/i:QueryResponse", nsmgr);
Google Docs:
Unfortunately, IMPORTXML() does not provide a namespace prefix binding mechanism. See next section, Defeating namespaces in XPath, for how to use local-name() as a work-around.
Java (SAX):
NamespaceSupport support = new NamespaceSupport();
support.pushContext();
support.declarePrefix("i", "http://schema.intuit.com/finance/v3");
Java (XPath):
xpath.setNamespaceContext(new NamespaceContext() {
public String getNamespaceURI(String prefix) {
switch (prefix) {
case "i": return "http://schema.intuit.com/finance/v3";
// ...
}
});
Remember to call
DocumentBuilderFactory.setNamespaceAware(true).
See also:
Java XPath: Queries with default namespace xmlns
JavaScript:
See Implementing a User Defined Namespace Resolver:
function nsResolver(prefix) {
var ns = {
'i' : 'http://schema.intuit.com/finance/v3'
};
return ns[prefix] || null;
}
document.evaluate( '/i:IntuitResponse/i:QueryResponse',
document, nsResolver, XPathResult.ANY_TYPE,
null );
Note that if the default namespace has an associated namespace prefix defined, using the nsResolver() returned by Document.createNSResolver() can obviate the need for a customer nsResolver().
Perl (LibXML):
my $xc = XML::LibXML::XPathContext->new($doc);
$xc->registerNs('i', 'http://schema.intuit.com/finance/v3');
my #nodes = $xc->findnodes('/i:IntuitResponse/i:QueryResponse');
Python (lxml):
from lxml import etree
f = StringIO('<IntuitResponse>...</IntuitResponse>')
doc = etree.parse(f)
r = doc.xpath('/i:IntuitResponse/i:QueryResponse',
namespaces={'i':'http://schema.intuit.com/finance/v3'})
Python (ElementTree):
namespaces = {'i': 'http://schema.intuit.com/finance/v3'}
root.findall('/i:IntuitResponse/i:QueryResponse', namespaces)
Python (Scrapy):
response.selector.register_namespace('i', 'http://schema.intuit.com/finance/v3')
response.xpath('/i:IntuitResponse/i:QueryResponse').getall()
PhP:
Adapted from #Tomalak's answer using DOMDocument:
$result = new DOMDocument();
$result->loadXML($xml);
$xpath = new DOMXpath($result);
$xpath->registerNamespace("i", "http://schema.intuit.com/finance/v3");
$result = $xpath->query("/i:IntuitResponse/i:QueryResponse");
See also #IMSoP's canonical Q/A on PHP SimpleXML namespaces.
Ruby (Nokogiri):
puts doc.xpath('/i:IntuitResponse/i:QueryResponse',
'i' => "http://schema.intuit.com/finance/v3")
Note that Nokogiri supports removal of namespaces,
doc.remove_namespaces!
but see the below warnings discouraging the defeating of XML namespaces.
VBA:
xmlNS = "xmlns:i='http://schema.intuit.com/finance/v3'"
doc.setProperty "SelectionNamespaces", xmlNS
Set queryResponseElement =doc.SelectSingleNode("/i:IntuitResponse/i:QueryResponse")
VB.NET:
xmlDoc = New XmlDocument()
xmlDoc.Load("file.xml")
nsmgr = New XmlNamespaceManager(New XmlNameTable())
nsmgr.AddNamespace("i", "http://schema.intuit.com/finance/v3");
nodes = xmlDoc.DocumentElement.SelectNodes("/i:IntuitResponse/i:QueryResponse",
nsmgr)
SoapUI (doc):
declare namespace i='http://schema.intuit.com/finance/v3';
/i:IntuitResponse/i:QueryResponse
xmlstarlet:
-N i="http://schema.intuit.com/finance/v3"
XSLT:
<xsl:stylesheet version="1.0"
xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
xmlns:i="http://schema.intuit.com/finance/v3">
...
Once you've declared a namespace prefix, your XPath can be written to use it:
/i:IntuitResponse/i:QueryResponse
Defeating namespaces in XPath (not recommended)
An alternative is to write predicates that test against local-name():
/*[local-name()='IntuitResponse']/*[local-name()='QueryResponse']
Or, in XPath 2.0:
/*:IntuitResponse/*:QueryResponse
Skirting namespaces in this manner works but is not recommended because it
Under-specifies the full element/attribute name.
Fails to differentiate between element/attribute names in different
namespaces (the very purpose of namespaces). Note that this concern could be addressed by adding an additional predicate to check the namespace URI explicitly:
/*[ namespace-uri()='http://schema.intuit.com/finance/v3'
and local-name()='IntuitResponse']
/*[ namespace-uri()='http://schema.intuit.com/finance/v3'
and local-name()='QueryResponse']
Thanks to Daniel Haley for the namespace-uri() note.
Is excessively verbose.
XPath 3.0/3.1
Libraries and tools that support modern XPath 3.0/3.1 allow the specification of a namespace URI directly in an XPath expression:
/Q{http://schema.intuit.com/finance/v3}IntuitResponse/Q{http://schema.intuit.com/finance/v3}QueryResponse
While Q{http://schema.intuit.com/finance/v3} is much more verbose than using an XML namespace prefix, it has the advantage of being independent of the namespace prefix binding mechanism of the hosting library. The Q{} notation is known as Clark Notation after its originator, James Clark. The W3C XPath 3.1 EBNF grammar calls it a BracedURILiteral.
Thanks to Michael Kay for the suggestion to cover XPath 3.0/3.1's BracedURILiteral.
I use /*[name()='...'] in a google sheet to fetch some counts from Wikidata. I have a table like this
thes WD prop links items
NOM P7749 3925 3789
AAT P1014 21157 20224
and the formulas in cols links and items are
=IMPORTXML("https://query.wikidata.org/sparql?query=SELECT(COUNT(*)as?c){?item wdt:"&$B14&"[]}","//*[name()='literal']")
=IMPORTXML("https://query.wikidata.org/sparql?query=SELECT(COUNT(distinct?item)as?c){?item wdt:"&$B14&"[]}","//*[name()='literal']")
respectively. The SPARQL query happens not to have any spaces...
I saw name() used instead of local-name() in Xml Namespace breaking my xpath!, and for some reason //*:literal doesn't work.
I am trying to retrieve the value of an attribute from an xmel file using XPath and I am not sure where I am going wrong..
This is the XML File
<soapenv:Envelope>
<soapenv:Header>
<common:TestInfo testID="PI1" />
</soapenv:Header>
</soapenv:Envelope>
And this is the code I am using to get the value. Both of these return nothing..
XPathBuilder getTestID = new XPathBuilder("local-name(/*[local-name(.)='Envelope']/*[local-name(.)='Header']/*[local-name(.)='TestInfo'])");
XPathBuilder getTestID2 = new XPathBuilder("Envelope/Header/TestInfo/#testID");
Object doc2 = getTestID.evaluate(context, sourceXML);
Object doc3 = getTestID2.evaluate(context, sourceXML);
How can I retrieve the value of testID?
However you're iterating within the java, your context node is probably not what you think, so remove the "." specifier in your local-name(.) like so:
/*[local-name()='Header']/*[local-name()='TestInfo']/#testID worked fine for me with your XML, although as akaIDIOT says, there isn't an <Envelope> tag to be seen.
The XML file you provided does not contain an <Envelope> element, so an expression that requires it will never match.
Post-edit edit
As can be seen from your XML snippet, the document uses a specific namespace for the elements you're trying to match. An XPath engine is namespace-aware, meaning you'll have to ask it exactly what you need. And, keep in mind that a namespace is defined by its uri, not by its abbreviation (so, /namespace:element doesn't do much unless you let the XPath engine know what the namespace namespace refers to).
Your first XPath has an extra local-name() wrapped around the whole thing:
local-name(/*[local-name(.)='Envelope']/*[local-name(.)='Header']
/*[local-name(.)='TestInfo'])
The result of this XPath will either be the string value "TestInfo" if the TestInfo node is found, or a blank string if it is not.
If your XML is structured like you say it is, then this should work:
/*[local-name()='Envelope']/*[local-name()='Header']/*[local-name()='TestInfo']/#testID
But preferably, you should be working with namespaces properly instead of (ab)using local-name(). I have a post here that shows how to do this in Java.
If you don't care for the namespaces and use an XPath 2.0 compatible engine, use * for it.
//*:Header/*:TestInfo/#testID
will return the desired input.
It will probably be more elegant to register the needed namespaces (not covered here, depends on your XPath engine) and query using these:
//soapenv:Header/common:TestInfo/#testID
I'll point out now, that I'm new to using saxon, and I've tried following the docs and examples in the package, but I'm just not having luck with this problem.
Basically, I'm trying to do some xml processing in java using saxon v8. In order to get something working, I took one of the sample files included in the package and modified to my needs. It works so long as I'm not using namespaces, and that is my question. How can I get around the namespace problem? I don't really care to use it, but it exists in my xml, so I either have to use it or ignore it. Either solution is fine.
Anyway, here is my starter code. It doesn't do anything but take an xpath query try to use it against the hard coded xml doc.
public static void main(String[] args) {
String query = args[0];
File XMLStream=null;
String xmlFileName="doc.xml";
OutputStream destStream=System.out;
XQueryExpression exp=null;
Configuration C=new Configuration();
C.setSchemaValidation(false);
C.setValidation(false);
StaticQueryContext SQC=new StaticQueryContext(C);
DynamicQueryContext DQC=new DynamicQueryContext(C);
QueryProcessor processor = new QueryProcessor(SQC);
Properties props=new Properties();
try{
exp=processor.compileQuery(query);
XMLStream=new File(xmlFileName);
InputSource XMLSource=new InputSource(XMLStream.toURI().toString());
SAXSource SAXs=new SAXSource(XMLSource);
DocumentInfo DI=SQC.buildDocument(SAXs);
DQC.setContextNode(DI);
SequenceIterator iter = exp.iterator(DQC);
while(true){
Item i = iter.next();
if(i != null){
System.out.println(i.getStringValue());
}
else break;
}
}
catch (Exception e){
System.err.println(e.getMessage());
}
}
An example XML file is here...
<?xml version="1.0"?>
<ns1:animal xmlns:ns1="http://my.catservice.org/">
<cat>
<catId>8889</catId>
<fedStatus>true</fedStatus>
</cat>
</ns1:animal>
If I run this with a query including the namespace, I get an error. For example:
/ns1:animal/cat/ gives the error: "Prefix ns1 has not been declared".
If I remove the ns1: from the query, it gives me nothing. If I doctor the xml to remove the "ns1:" prepended to "animal" I can run the query /animal/cat/ with success.
Any help would be greatly appreciated. Thanks.
Error message correctly points out that your xpath expression does not indicate what namespace prefix "ns1" means (binds to). Just because document to operate on happens to use binding for "ns1" does not mean it is what should be used: this because in XML, it's the namespace URI that matters, and prefixes are just convenient shortcuts to the real thing.
So: how do you define the binding? There are 2 generic ways; either provide a context that can resolve the prefix, or embed actual URI within XPath expression.
Regarding the first approach, this email from Saxon author mentions JAXP method XPath.setNamespaceContext(), similarly, Jaxen XPath processor FAQ has some sample code that could help
That's not very convenient, as you have to implement NamespaceContext, but once you have an implementation you'll be set.
So the notation approach... let's see: Top Ten Tips to Using XPath and XPointer shows this example:
to match element declared with namespace like:
xmlns:book="http://my.example.org/namespaces/book"
you use XPath name like:
{http://my.example.org/namespaces/book}section
which hopefully is understood by Saxon (or Jaxen).
Finally, I would recommend upgrading to Saxon9 if possible, if you have any trouble using one of above solutions.
If you want to have something working out of the box, you can check out embedding-xquery-in-java. There's github project, which uses Saxon to evaluate some sample XQuery expressions.
Regards