Analyser XML with namespaces
XML namespaces qualify element names en avoid collisions. Apprendre le xmlns declaration, default vs prefixed namespaces, et comment en analyser them correctly.
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XML namespaces use URIs to disambiguate element names. A namespace is declared with xmlns="uri" (default) or xmlns:prefix="uri" (prefixed). Elements are then qualified: <prefix:element>. The namespace URI is the identifier — the prefix is just a shorthand. Two elements with the same local name but different namespaces are different elements.
- 2 Formateur XML →
Formater the XML to see namespace declarations clearly. The formatter shows which prefixes map to which URIs. Verify that all prefixed elements have a corresponding xmlns declaration in scope.
- 3 Convertisseur JSON ↔ XML →
Convertir namespaced XML to JSON. Namespace-qualified elements typically become prefixed keys: <ns:element> → "ns:element" or "{uri}element" depending on the converter. Understand your converter's namespace handling en query the correct keys
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Common namespaces: xmlns="http://www.w3.org/1999/xhtml" (XHTML), xmlns:svg="http://www.w3.org/2000/svg" (SVG), xmlns:atom="http://www.w3.org/2005/Atom" (Atom feeds). When parsing, match on the namespace URI, not the prefix — prefixes can be reassigned. Use XPath with namespace resolvers for robust querying.
Questions fréquentes
- Why use namespaces?
- To combine XML vocabularies without name collisions. For example, XHTML and SVG both have a <title> element — namespaces distinguish <xhtml:title> from <svg:title>. Without namespaces, a parser cannot tell them apart.
- Is the prefix significant?
- No — the namespace URI is the identifier, not the prefix. <foo:bar xmlns:foo="urn:x"> and <baz:bar xmlns:baz="urn:x"> are the same element. When comparing or querying, always use the URI, not the prefix. Prefixes are arbitrary shorthand.