Improved namespace support

The previous namespace support did not handle documents containing multiply
namespaced nodes.  It also made assumptions about the 'default' namespace
when multiple prefixed namespaces were provided (with no implicit default).

This patch allows namespaces to be set item-wide (via 'namespace <ns>' in
the class) or on a per-element basis (via :namespace => <ns> on the
element mapping).

Signed-off-by: John Nunemaker <nunemaker@gmail.com>

examples/amazon.rb

@@ -3,6 +3,8 @@
 
 file_contents = File.read(dir + '/../spec/fixtures/pita.xml')
 
+# The document `pita.xml` contains both a default namespace and the 'georss'
+# namespace (for the 'point' element).
 module PITA
   class Item
     include HappyMapper
@@ -11,6 +13,9 @@ class Item
     element :asin, String, :tag => 'ASIN'
     element :detail_page_url, String, :tag => 'DetailPageURL'
     element :manufacturer, String, :tag => 'Manufacturer', :deep => true
+    # this is the only element that exists in a different namespace, so it
+    # must be explicitly specified
+    element :point, String, :tag => 'point', :namespace => 'georss'
   end
 
   class Items

lib/happymapper.rb

@@ -13,7 +13,9 @@
 class Boolean; end
 
 module HappyMapper
-
+
+  DEFAULT_NS = "happymapper"
+
   def self.included(base)
     base.instance_variable_set("@attributes", {})
     base.instance_variable_set("@elements", {})
@@ -50,7 +52,15 @@ def has_one(name, type, options={})
     def has_many(name, type, options={})
       element name, type, {:single => false}.merge(options)
     end
-
+
+    # Specify a namespace if a node and all its children are all namespaced
+    # elements. This is simpler than passing the :namespace option to each
+    # defined element.
+    def namespace(namespace = nil)
+      @namespace = namespace if namespace
+      @namespace
+    end
+
     # Options:
     #   :root => Boolean, true means this is xml root
     def tag(new_tag_name, o={})
@@ -71,24 +81,30 @@ def is_root?
 
     def parse(xml, o={})      
       xpath, collection, options = '', [], {:single => false}.merge(o)
-      doc   = xml.is_a?(LibXML::XML::Node) ? xml : xml.to_libxml_doc
-      node  = doc.respond_to?(:root) ? doc.root : doc
-
-      # puts doc.inspect, doc.respond_to?(:root) ? doc.root.inspect : ''
-
-      unless node.namespaces.default.nil?
-        namespace = "default_ns:" 
-        node.namespaces.default_prefix = namespace.chop
-        # warn "Default XML namespace present -- results are unpredictable" 
+
+      # reset the namespace if it was set to the default
+      # this is necessary when using the same object mapping instance for
+      # docs w/ and w/o default namespaces
+      @namespace = nil if @namespace == DEFAULT_NS
+
+      if xml.is_a?(XML::Node)
+        node = xml
+      elsif xml.is_a?(XML::Document)
+        node = xml.root
+      else
+        node = xml.to_libxml_doc.root
       end
-
-      if node.namespaces.to_a.size > 0 && namespace.nil? && !node.namespaces.namespace.nil?
-        namespace = node.namespaces.namespace.prefix + ":" 
+
+      # This is the entry point into the parsing pipeline, so the default
+      # namespace prefix registered here will propagate down
+      namespaces = node.namespaces
+      if namespaces && namespaces.default
+        namespaces.default_prefix = DEFAULT_NS
+        @namespace ||= DEFAULT_NS
       end
-
-      # xpath += doc.respond_to?(:root) ? '' : '.'
+
       xpath += is_root? ? '/' : './/'
-      xpath += namespace  if namespace
+      xpath += "#{namespace}:" if namespace
       xpath += get_tag_name
       # puts "parse: #{xpath}"
 
@@ -102,7 +118,7 @@ def parse(xml, o={})
         end
 
         elements.each do |elem|
-          elem.namespace = namespace
+          elem.namespace ||= namespace
           obj.send("#{elem.method_name}=", 
                     elem.from_xml_node(n))
         end

lib/happymapper/item.rb

@@ -7,11 +7,15 @@ class Item
     # options:
     #   :deep   =>  Boolean False to only parse element's children, True to include
     #               grandchildren and all others down the chain (// in expath)
+    #   :namespace => String Element's namespace if it's not the global or inherited
+    #                  default
     #   :single =>  Boolean False if object should be collection, True for single object
+    #   :tag    =>  String Element name if it doesn't match the specified name.
     def initialize(name, type, o={})
       self.name = name.to_s
       self.type = type
       self.tag = o.delete(:tag) || name.to_s
+      self.namespace = o[:namespace]
       self.options = {
         :single => false, 
         :deep   => false,
@@ -33,7 +37,7 @@ def from_xml_node(node)
     def xpath
       xpath  = ''
       xpath += './/' if options[:deep]
-      xpath += namespace if namespace
+      xpath += "#{namespace}:" if namespace
       xpath += tag
       # puts "xpath: #{xpath}"
       xpath
@@ -87,6 +91,11 @@ def typecast(value)
 
     private
       def value_from_xml_node(node)
+        # this node has a custom namespace (that is present in the doc)
+        if namespace && !node.namespaces.find_by_prefix(namespace)
+          self.namespace = nil
+        end
+
         if element?
           result = node.find_first(xpath)
           # puts "vfxn: #{xpath} #{result.inspect}"

spec/fixtures/pita.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<ItemSearchResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2005-10-05">
+<ItemSearchResponse xmlns="http://webservices.amazon.com/AWSECommerceService/2005-10-05" xmlns:georss="http://www.georss.org/georss">
 	<OperationRequest>
 		<HTTPHeaders>
 			<Header Name="UserAgent">
@@ -27,6 +27,7 @@
 		<TotalPages>3</TotalPages>
 		<Item>
 			<ASIN>0321480791</ASIN>
+			<georss:point>38.5351715088 -121.7948684692</georss:point>
 		<DetailPageURL>http://www.amazon.com/gp/redirect.html%3FASIN=0321480791%26tag=ws%26lcode=xm2%26cID=2025%26ccmID=165953%26location=/o/ASIN/0321480791%253FSubscriptionId=dontbeaswoosh</DetailPageURL>
 			<ItemAttributes>
 				<Author>Michael Hartl</Author>

spec/happymapper_item_spec.rb

@@ -44,7 +44,7 @@
 
     it "should prepend namespace if namespace exists" do
       item = HappyMapper::Item.new(:foo, String, :tag => 'foobar')
-      item.namespace = 'v2:'
+      item.namespace = 'v2'
       item.xpath.should == 'v2:foobar'
     end
   end

spec/happymapper_spec.rb

@@ -51,6 +51,7 @@ class Address
     include HappyMapper
 
     tag 'Address'
+    namespace 'v2'
     element :city, String, :tag => 'City'
     element :state, String, :tag => 'StateOrProvinceCode'
     element :zip, String, :tag => 'PostalCode'
@@ -62,6 +63,7 @@ class Event
     include HappyMapper
 
     tag 'Events'
+    namespace 'v2'
     element :timestamp, String, :tag => 'Timestamp'
     element :eventtype, String, :tag => 'EventType'
     element :eventdescription, String, :tag => 'EventDescription'
@@ -72,6 +74,7 @@ class PackageWeight
     include HappyMapper
 
     tag 'PackageWeight'
+    namespace 'v2'
     element :units, String, :tag => 'Units'
     element :value, Integer, :tag => 'Value'
   end
@@ -80,6 +83,7 @@ class TrackDetails
     include HappyMapper
 
     tag 'TrackDetails'
+    namespace 'v2'
     element   :tracking_number, String, :tag => 'TrackingNumber'
     element   :status_code, String, :tag => 'StatusCode'
     element   :status_desc, String, :tag => 'StatusDescription'
@@ -94,6 +98,7 @@ class Notification
     include HappyMapper
 
     tag 'Notifications'
+    namespace 'v2'
     element :severity, String, :tag => 'Severity'
     element :source, String, :tag => 'Source'
     element :code, Integer, :tag => 'Code'
@@ -105,13 +110,15 @@ class TransactionDetail
     include HappyMapper
 
     tag 'TransactionDetail'
+    namespace 'v2'
     element :cust_tran_id, String, :tag => 'CustomerTransactionId'
   end
 
   class TrackReply
     include HappyMapper
 
     tag 'TrackReply', :root => true
+    namespace 'v2'
     element   :highest_severity, String, :tag => 'HighestSeverity'
     element   :more_data, Boolean, :tag => 'MoreData'
     has_many  :notifications, Notification, :tag => 'Notifications'
@@ -167,13 +174,15 @@ class Status
 	element :in_reply_to_status_id, Integer
 	element :in_reply_to_user_id, Integer
 	element :favorited, Boolean
+	element :non_existent, String, :tag => 'dummy', :namespace => 'fake'
 	has_one :user, User
 end
 
 class CurrentWeather
   include HappyMapper
 
   tag 'ob'
+  namespace 'aws'
   element :temperature, Integer, :tag => 'temp'
   element :feels_like, Integer, :tag => 'feels-like'
   element :current_condition, String, :tag => 'current-condition', :attributes => {:icon => String}
@@ -198,6 +207,7 @@ class Item
     element :asin, String, :tag => 'ASIN'
     element :detail_page_url, String, :tag => 'DetailPageURL'
     element :manufacturer, String, :tag => 'Manufacturer', :deep => true
+    element :point, String, :tag => 'point', :namespace => 'georss'
   end
 
   class Items
@@ -290,7 +300,7 @@ class Foo; include HappyMapper end
       element.type.should == User
       element.options[:single] = false
     end
-    
+
     it "should default tag name to lowercase class" do
       Foo.get_tag_name.should == 'foo'
     end
@@ -305,6 +315,11 @@ module Bar; class Baz; include HappyMapper; end; end
       Foo.get_tag_name.should == 'FooBar'
     end
 
+    it "should allow setting a namespace" do
+      Foo.namespace(namespace = "foo")
+      Foo.namespace.should == namespace
+    end
+
     it "should provide #parse" do
       Foo.should respond_to(:parse)
     end
@@ -320,7 +335,7 @@ module Bar; class Baz; include HappyMapper; end; end
   describe "#elements" do
     it "should only return elements for the current class" do
       Post.elements.size.should == 0
-      Status.elements.size.should == 9
+      Status.elements.size.should == 10
     end
   end
 
@@ -376,6 +391,7 @@ module Bar; class Baz; include HappyMapper; end; end
     first  = items.items[0]
     second = items.items[1]
     first.asin.should == '0321480791'
+    first.point.should == '38.5351715088 -121.7948684692'
     first.detail_page_url.should == 'http://www.amazon.com/gp/redirect.html%3FASIN=0321480791%26tag=ws%26lcode=xm2%26cID=2025%26ccmID=165953%26location=/o/ASIN/0321480791%253FSubscriptionId=dontbeaswoosh'
     first.manufacturer.should == 'Addison-Wesley Professional'
     second.asin.should == '047022388X'