== amazon-ecsGeneric Product Advertising Ruby API using Nokogiri. Uses Response and Element wrapper classes for easy access to the REST API XML output.It is generic, so you can easily extend <tt>Amazon::Ecs</tt> to support other not implemented REST operations; and it is also generic because it just wraps arounda Nokogiri Node object, instead of providing one-to-one object/attributes to XML elements map.The idea is as the API evolves, there is a change in REST XML output structure, no updates will be required on <tt>amazon-ecs</tt> gem, instead you just need to update the element path. == INSTALLATION  $ gem install amazon-ecsGemfilegem 'amazon-ecs', :git => 'git://github.com/wrobbins/amazon-ecs.git'== EXAMPLE    require "amazon/ecs"    # set the default options; options will be camelized and converted to REST request parameters.    Amazon::Ecs.options = {:aWS_access_key_id => "[your access key]"}    # to generate signed requests include your secret key:    Amazon::Ecs.options = {:aWS_access_key_id => "[your developer token]", :aWS_secret_key => "[your secret access key]"}    # alternatively,    Amazon::Ecs.configure do |options|        options[:aWS_access_key_id] = "[your access key]"        options[:aWS_secret_key] = "[you secret key]"    end    # options provided on method call will merge with the default options    res = Amazon::Ecs.item_search("ruby", {:response_group => "Medium", :sort => "salesrank"})    # some common response object methods    res.is_valid_request?     # return true if request is valid    res.has_error?            # return true if there is an error    res.error                 # return error message if there is any    res.total_pages           # return total pages    res.total_results         # return total results    res.item_page             # return current page no if :item_page option is provided    # traverse through each item (Amazon::Element)    res.items.each do |item|      # retrieve string value using XML path      item.get("asin")      item.get("itemattributes/title")      # return Amazon::Element instance      item_attributes = item.get_element("itemattributes")      item_attributes.get("title")        # return first author or a string array of authors      item_attributes.get("author")          # "Author 1"      item_attributes.get_array("author")    # ["Author 1", "Author 2", ...]        # return an hash of children text values with the element names as the keys      item.get_hash("smallimage") # {:url => ..., :width => ..., :height => ...}      # return the first matching path as Amazon::Element      item_height = item.get_element("itemdimensions/height")            # retrieve attributes from Amazon::Element      item_height.attributes["units"]   # "hundredths-inches"            # return an array of Amazon::Element      authors = item.get_elements("author")        # return Nokogiri::XML::NodeSet object or nil if not found      reviews = item/"editorialreview"        # traverse through Nokogiri Node elements      reviews.each do |review|        # Getting hash value out of Nokogiri element        Amazon::Element.get_hash(review) # [:source => ..., :content ==> ...]            # Or to get unescaped HTML values        Amazon::Element.get_unescaped(review, "source")        Amazon::Element.get_unescaped(review, "content")                # Or this way        el = Amazon::Element.new(review)        el.get_unescaped("source")        el.get_unescaped("content")      end    end        # Extend Amazon::Ecs, replace 'other_operation' with the appropriate name    module Amazon      class Ecs        def self.other_operation(item_id, opts={})          opts[:operation] = '[other valid operation supported by Product Advertising API]'                    # setting default option value          opts[:item_id] = item_id                  self.send_request(opts)        end      end    end        Amazon::Ecs.other_operation("[item_id]", :param1 => "abc", :param2 => "xyz")Refer to Amazon Product Advertising API documentation for more information on other valid operations, request parameters and the XML response output:https://affiliate-program.amazon.com/gp/advertising/api/detail/main.htmlTo get a sample of Amazon REST XML response output, use AWSZone.com scratch pad:http://www.awszone.com/scratchpads/aws/ecs.us/index.aws== SOURCE CODES*http://github.com/jugend/amazon-ecs== CREDITSThanks to Dan Milne (http://da.nmilne.com/) for the signed request patch.== LICENSE(The MIT License)Copyright (c) 2010 Herryanto Siatono,http://www.siatono.com