Reference to undeclared namespace prefix when parsing MSXML

https://stackoverflow.com/questions/5951628

07-11-2019
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سؤال

How do I solve the

Reference to undeclared namespace prefix: '%s'

problem with Microsoft's msxml implementation?

I'm using an XML feed from a government web-site that contains values i need to parse. The xml contains namespaces:

<?xml version="1.0" encoding="ISO-8859-1"?>
<rdf:RDF
    xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
    xmlns="http://purl.org/rss/1.0/"
    xmlns:cb="http://www.cbwiki.net/wiki/index.php/Specification_1.1"
    xmlns:dc="http://purl.org/dc/elements/1.1/"
    xmlns:dcterms="http://purl.org/dc/terms/"
    xmlns:xsi="http://www.w3c.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.w3c.org/1999/02/22-rdf-syntax-ns#rdf.xsd">
    <item rdf:about="http://www.bankofcanada.ca/stats/rates_rss/STATIC_IEXE0101.xml">
        <cb:statistics>
            <cb:exchangeRate>
                <cb:value decimals="4">1.0351</cb:value>
                <cb:baseCurrency>CAD</cb:baseCurrency>
                <cb:targetCurrency>USD</cb:targetCurrency>
                <cb:rateType>Bank of Canada noon rate</cb:rateType>
                <cb:observationPeriod frequency="daily">2011-05-09T12:15:00-04:00</cb:observationPeriod>
            </cb:exchangeRate>
        </cb:statistics>
    </item>
</rdf:RDF>

Running the XPath query:

/rdf:RDF/item/cb:statistics/cb:exchangeRate/cb:targetCurrency

fails with the error:

Reference to undeclared namespace prefix: 'rdf'

Edit:

If i edit the original XML to remove all use of namespaces:

<?xml version="1.0" encoding="ISO-8859-1"?>
<rdf>
    <item>
        <statistics>
            <exchangeRate>
                <value decimals="4">1.0351</value>
                <baseCurrency>CAD</baseCurrency>
                <targetCurrency>USD</targetCurrency>
                <rateType>Bank of Canada noon rate</rateType>
                <observationPeriod frequency="daily">2011-05-09T12:15:00-04:00</observationPeriod>
            </exchangeRate>
        </statistics>
    </item>
</rdf>

The query /rdf/item/statistics/exchangeRate/baseCurrency doesn't fail, and returns nodes:

<baseCurrency>CAD</baseCurrency>

How do i get Microsoft XML to work with namespaces?

Edit 2

i've tried adding SelectionNamespaces to the DOMDocument object:

doc.setProperty('SelectionNamespaces', 'xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:cb="http://www.cbwiki.net/wiki/index.php/Specification_1.1"');

Now the xpath query doesn't fail, but it also returns no nodes:

nodes = doc.selectNodes('/rdf:RDF/item/cb:statistics/cb:exchangeRate/cb:targetCurrency');

Reference to undeclared namespace prefix when parsing MSXML

Edit 2

See also