chensoren · April 16, 2012 06:59 · May 5, 2011
diff --git a/NokogiriXPathNamespaces b/NokogiriXPathNamespaces
@@ -0,0 +1,19 @@
+2 ways to extract elements from within XML namespaces using Nokogiri
+When trying to select elemenets in the default namespace, e.g. "xmlns= http://www.w3.org/2005/Atom", try the following two ways. Note the xmlns=" attribute on entry element:
+
+Original xml:
+Nokogiri::XML(@xml_string).xpath("//author/name").each do |node|
+    puts node
+  end
+
+
+1. Define a namespace context for your XPath expression and point your XPath steps to match elements in that namespace. Define a namespace-to-prefix mapping and use this prefix (a) in the XPath expression.
+xml.xpath("//a:author/a:name", {"a" => "http://www.w3.org/2005/Atom"})
+
+2. LESS FAVORED: Using remove_namespaces! all your elements are under http://schemas.google.com/docs/2007 namespace URI. You must declare the binding bettween this URI an some prefix, say atom, and then the XPath expresion should be /*/atom:author/atom:name
+ xml = Nokogiri::XML(@xml_string)
+    xml.remove_namespaces!
+    xml.xpath("//author/name").each do |node|
+      puts node.text
+    end
+