ruby-on-rails - 如何使用 'amazon-ecs' gem 获取属性？

Question

我正在使用Amazon Product Advertising API (amazon-ecs) gem，但我使用的是 item_lookup 方法，而不是 item_search，这是唯一记录的方法。

我希望退回商品TradeInValue，但我对如何操作感到困惑。显然正在返回，但我不知道如何解析它。

这是电话:

Amazon::Ecs.item_lookup('9780521153348', :response_group => 'ItemAttributes', :id_type => 'ISBN', :search_index => 'Books')

这就是返回，我不知道该怎么处理。 amazon-ecs 中的方法似乎不适用于 item_lookup 并且 XPath 也不起作用:

#<Amazon::Ecs::Response:0x007ff3325250d0 @doc=#<Nokogiri::XML::Document:0x3ff9992927a0 name="document" children=[#<Nokogiri::XML::Element:0x3ff997067414 name="ItemLookupResponse" children=[#<Nokogiri::XML::Element:0x3ff99706b924 name="OperationRequest" children=[#<Nokogiri::XML::Element:0x3ff99706b474 name="HTTPHeaders" children=[#<Nokogiri::XML::Element:0x3ff99706f470 name="Header" attributes=[#<Nokogiri::XML::Attr:0x3ff99706f0ec name="Name" value="UserAgent">, #<Nokogiri::XML::Attr:0x3ff99706f074 name="Value" value="Ruby">]>]>, #<Nokogiri::XML::Element:0x3ff9970760cc name="RequestId" children=[#<Nokogiri::XML::Text:0x3ff999296468 "053626d3-e3cd-47d2-bc8b-7ac6a0c5f6d2">]>, #<Nokogiri::XML::Element:0x3ff99929f6f8 name="Arguments" children=[#<Nokogiri::XML::Element:0x3ff9992a3bb8 name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992a3960 name="Name" value="Operation">, #<Nokogiri::XML::Attr:0x3ff9992a3938 name="Value" value="ItemLookup">]>, #<Nokogiri::XML::Element:0x3ff9992a73f8 name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992a7204 name="Name" value="Signature">, #<Nokogiri::XML::Attr:0x3ff9992a7010 name="Value" value="IMd3D0DGgAcaLR6XcuObzdAgFbOya7mbIRtZFbNijVA=">]>, #<Nokogiri::XML::Element:0x3ff9992ab41c name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992ab2dc name="Name" value="AssociateTag">, #<Nokogiri::XML::Attr:0x3ff9992ab2c8 name="Value" value="textscom-20">]>, #<Nokogiri::XML::Element:0x3ff9992af774 name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992af6ac name="Name" value="ItemId">, #<Nokogiri::XML::Attr:0x3ff9992af698 name="Value" value="9780521153348">]>, #<Nokogiri::XML::Element:0x3ff9992b0c3c name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992b0b4c name="Name" value="IdType">, #<Nokogiri::XML::Attr:0x3ff9992b0b10 name="Value" value="ISBN">]>, #<Nokogiri::XML::Element:0x3ff9992b7794 name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992b7578 name="Name" value="AWSAccessKeyId">, #<Nokogiri::XML::Attr:0x3ff9992b7550 name="Value" value="AKIAJLOCEGWTFXZKXLEQ">]>, #<Nokogiri::XML::Element:0x3ff9992b2244 name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992b208c name="Name" value="Timestamp">, #<Nokogiri::XML::Attr:0x3ff9992b2064 name="Value" value="2013-05-07T17:46:35Z">]>, #<Nokogiri::XML::Element:0x3ff9992bffc0 name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992bff20 name="Name" value="ResponseGroup">, #<Nokogiri::XML::Attr:0x3ff9992bff0c name="Value" value="ItemAttributes">]>, #<Nokogiri::XML::Element:0x3ff9992be1e8 name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992c38c8 name="Name" value="SearchIndex">, #<Nokogiri::XML::Attr:0x3ff9992c3a30 name="Value" value="Books">]>, #<Nokogiri::XML::Element:0x3ff9992ca95c name="Argument" attributes=[#<Nokogiri::XML::Attr:0x3ff9992ca344 name="Name" value="Service">, #<Nokogiri::XML::Attr:0x3ff9992ca2a4 name="Value" value="AWSECommerceService">]>]>, #<Nokogiri::XML::Element:0x3ff9992d3d7c name="RequestProcessingTime" children=[#<Nokogiri::XML::Text:0x3ff9992d382c "0.0289960000000000">]>]>, #<Nokogiri::XML::Element:0x3ff9992d7eb8 name="Items" children=[#<Nokogiri::XML::Element:0x3ff9992d7148 name="Request" children=[#<Nokogiri::XML::Element:0x3ff9992d6900 name="IsValid" children=[#<Nokogiri::XML::Text:0x3ff9992dae10 "True">]>, #<Nokogiri::XML::Element:0x3ff9992da758 name="ItemLookupRequest" children=[#<Nokogiri::XML::Element:0x3ff9992df884 name="IdType" children=[#<Nokogiri::XML::Text:0x3ff9992df014 "ISBN">]>, #<Nokogiri::XML::Element:0x3ff9992de678 name="ItemId" children=[#<Nokogiri::XML::Text:0x3ff9992e2e1c "9780521153348">]>, #<Nokogiri::XML::Element:0x3ff9983a5580 name="ResponseGroup" children=[#<Nokogiri::XML::Text:0x3ff9983a59b8 "ItemAttributes">]>, #<Nokogiri::XML::Element:0x3ff9983a510c name="SearchIndex" children=[#<Nokogiri::XML::Text:0x3ff9983a43c4 "Books">]>, #<Nokogiri::XML::Element:0x3ff9983a925c name="VariationPage" children=[#<Nokogiri::XML::Text:0x3ff9983a8d0c "All">]>]>]>, #<Nokogiri::XML::Element:0x3ff9983a8244 name="Item" children=[#<Nokogiri::XML::Element:0x3ff9983add70 name="ASIN" children=[#<Nokogiri::XML::Text:0x3ff9983ad6f4 "0521153344">]>, #<Nokogiri::XML::Element:0x3ff9983acc04 name="DetailPageURL" children=[#<Nokogiri::XML::Text:0x3ff9983ac4d4 "http://www.amazon.com/Turgot-Progress-Sociology-Economics-Philosophical/dp/0521153344%3FSubscriptionId%3DAKIAJLOCEGWTFXZKXLEQ%26tag%3Dtextscom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D165953%26creativeASIN%3D0521153344">]>, #<Nokogiri::XML::Element:0x3ff9983b1768 name="ItemLinks" children=[#<Nokogiri::XML::Element:0x3ff9983b1024 name="ItemLink" children=[#<Nokogiri::XML::Element:0x3ff9983b0a20 name="Description" children=[#<Nokogiri::XML::Text:0x3ff9983b028c "Technical Details">]>, #<Nokogiri::XML::Element:0x3ff9983b5b60 name="URL" children=[#<Nokogiri::XML::Text:0x3ff9983b5638 "http://www.amazon.com/Turgot-Progress-Sociology-Economics-Philosophical/dp/tech-data/0521153344%3FSubscriptionId%3DAKIAJLOCEGWTFXZKXLEQ%26tag%3Dtextscom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3D0521153344">]>]>, #<Nokogiri::XML::Element:0x3ff9983b5034 name="ItemLink" children=[#<Nokogiri::XML::Element:0x3ff9983b4a58 name="Description" children=[#<Nokogiri::XML::Text:0x3ff9983b46d4 "Add To Baby Registry">]>, #<Nokogiri::XML::Element:0x3ff9983b406c name="URL" children=[#<Nokogiri::XML::Text:0x3ff9983b9ad0 "http://www.amazon.com/gp/registry/baby/add-item.html%3Fasin.0%3D0521153344%26SubscriptionId%3DAKIAJLOCEGWTFXZKXLEQ%26tag%3Dtextscom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3D0521153344">]>]>, #<Nokogiri::XML::Element:0x3ff9983b95d0 name="ItemLink" children=[#<Nokogiri::XML::Element:0x3ff9983b9080 name="Description" children=[#<Nokogiri::XML::Text:0x3ff9983b8cd4 "Add To Wedding Registry">]>, #<Nokogiri::XML::Element:0x3ff9983b8a2c name="URL" children=[#<Nokogiri::XML::Text:0x3ff9983b834c "http://www.amazon.com/gp/registry/wedding/add-item.html%3Fasin.0%3D0521153344%26SubscriptionId%3DAKIAJLOCEGWTFXZKXLEQ%26tag%3Dtextscom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3D0521153344">]>]>, #<Nokogiri::XML::Element:0x3ff9983bcff0 name="ItemLink" children=[#<Nokogiri::XML::Element:0x3ff9983bc49c name="Description" children=[#<Nokogiri::XML::Text:0x3ff9983bc0f0 "Add To Wishlist">]>, #<Nokogiri::XML::Element:0x3ff9983c1b40 name="URL" children=[#<Nokogiri::XML::Text:0x3ff9983c158c "http://www.amazon.com/gp/registry/wishlist/add-item.html%3Fasin.0%3D0521153344%26SubscriptionId%3DAKIAJLOCEGWTFXZKXLEQ%26tag%3Dtextscom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3D0521153344">]>]>, #<Nokogiri::XML::Element:0x3ff9983c01dc name="ItemLink" children=[#<Nokogiri::XML::Element:0x3ff9983c5da8 name="Description" children=[#<Nokogiri::XML::Text:0x3ff9983c595c "Tell A Friend">]>, #<Nokogiri::XML::Element:0x3ff9983c5358 name="URL" children=[#<Nokogiri::XML::Text:0x3ff9983c4674 "http://www.amazon.com/gp/pdp/taf/0521153344%3FSubscriptionId%3DAKIAJLOCEGWTFXZKXLEQ%26tag%3Dtextscom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3D0521153344">]>]>, #<Nokogiri::XML::Element:0x3ff9983c9750 name="ItemLink" children=[#<Nokogiri::XML::Element:0x3ff9983c8828 name="Description" children=[#<Nokogiri::XML::Text:0x3ff9983cc888 "All Customer Reviews">]>, #<Nokogiri::XML::Element:0x3ff9983d1f18 name="URL" children=[#<Nokogiri::XML::Text:0x3ff9983d19c8 "http://www.amazon.com/review/product/0521153344%3FSubscriptionId%3DAKIAJLOCEGWTFXZKXLEQ%26tag%3Dtextscom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3D0521153344">]>]>, #<Nokogiri::XML::Element:0x3ff9983d152c name="ItemLink" children=[#<Nokogiri::XML::Element:0x3ff9983d107c name="Description" children=[#<Nokogiri::XML::Text:0x3ff9983d02d0 "All Offers">]>, #<Nokogiri::XML::Element:0x3ff9983d5730 name="URL" children=[#<Nokogiri::XML::Text:0x3ff9983d4e48 "http://www.amazon.com/gp/offer-listing/0521153344%3FSubscriptionId%3DAKIAJLOCEGWTFXZKXLEQ%26tag%3Dtextscom-20%26linkCode%3Dxm2%26camp%3D2025%26creative%3D386001%26creativeASIN%3D0521153344">]>]>]>, #<Nokogiri::XML::Element:0x3ff9983dd00c name="ItemAttributes" children=[#<Nokogiri::XML::Element:0x3ff9983dc33c name="Author" children=[#<Nokogiri::XML::Text:0x3ff9983e1364 "Ronald L. Meek">]>, #<Nokogiri::XML::Element:0x3ff9983e0af4 name="Binding" children=[#<Nokogiri::XML::Text:0x3ff9983e04a0 "Paperback">]>, #<Nokogiri::XML::Element:0x3ff9983e0068 name="EAN" children=[#<Nokogiri::XML::Text:0x3ff9983e5c34 "9780521153348">]>, #<Nokogiri::XML::Element:0x3ff9983e5270 name="EANList" children=[#<Nokogiri::XML::Element:0x3ff9983e4424 name="EANListElement" children=[#<Nokogiri::XML::Text:0x3ff9983d7c60 "9780521153348">]>]>, #<Nokogiri::XML::Element:0x3ff9983d7724 name="ISBN" children=[#<Nokogiri::XML::Text:0x3ff9983d7120 "0521153344">]>, #<Nokogiri::XML::Element:0x3ff9983d6cc0 name="IsEligibleForTradeIn" children=[#<Nokogiri::XML::Text:0x3ff9983d6130 "1">]>, #<Nokogiri::XML::Element:0x3ff9983d99c0 name="ItemDimensions" children=[#<Nokogiri::XML::Element:0x3ff9983d963c name="Height" attributes=[#<Nokogiri::XML::Attr:0x3ff9983d959c name="Units" value="hundredths-inches">] children=[#<Nokogiri::XML::Text:0x3ff9983d83cc "902">]>, #<Nokogiri::XML::Element:0x3ff9983ed7a4 name="Length" attributes=[#<Nokogiri::XML::Attr:0x3ff9983ed448 name="Units" value="hundredths-inches">] children=[#<Nokogiri::XML::Text:0x3ff9983f3244 "598">]>, #<Nokogiri::XML::Element:0x3ff9983f290c name="Weight" attributes=[#<Nokogiri::XML::Attr:0x3ff9983f26f0 name="Units" value="hundredths-pounds">] children=[#<Nokogiri::XML::Text:0x3ff9983e93c0 "64">]>, #<Nokogiri::XML::Element:0x3ff9983e8f38 name="Width" attributes=[#<Nokogiri::XML::Attr:0x3ff9983e8e34 name="Units" value="hundredths-inches">] children=[#<Nokogiri::XML::Text:0x3ff9983efa2c "43">]>]>, #<Nokogiri::XML::Element:0x3ff9983ef144 name="Label" children=[#<Nokogiri::XML::Text:0x3ff9983eecbc "Cambridge University Press">]>, #<Nokogiri::XML::Element:0x3ff9983ee988 name="Languages" children=[#<Nokogiri::XML::Element:0x3ff9983ee410 name="Language" children=[#<Nokogiri::XML::Element:0x3ff99a80009c name="Name" children=[#<Nokogiri::XML::Text:0x3ff99a801a14 "English">]>, #<Nokogiri::XML::Element:0x3ff99a8010f0 name="Type" children=[#<Nokogiri::XML::Text:0x3ff99a800948 "Unknown">]>]>, #<Nokogiri::XML::Element:0x3ff99a800574 name="Language" children=[#<Nokogiri::XML::Element:0x3ff99a8002b8 name="Name" children=[#<Nokogiri::XML::Text:0x3ff99a80419c "English">]>, #<Nokogiri::XML::Element:0x3ff99a805484 name="Type" children=[#<Nokogiri::XML::Text:0x3ff99a804b10 "Original Language">]>]>, #<Nokogiri::XML::Element:0x3ff99a804070 name="Language" children=[#<Nokogiri::XML::Element:0x3ff99a808d64 name="Name" children=[#<Nokogiri::XML::Text:0x3ff99a80d6d4 "English">]>, #<Nokogiri::XML::Element:0x3ff99a80c680 name="Type" children=[#<Nokogiri::XML::Text:0x3ff99a8110a4 "Published">]>]>]>, #<Nokogiri::XML::Element:0x3ff99a8157a8 name="ListPrice" children=[#<Nokogiri::XML::Element:0x3ff99a8142cc name="Amount" children=[#<Nokogiri::XML::Text:0x3ff99a819358 "2899">]>, #<Nokogiri::XML::Element:0x3ff99a818d04 name="CurrencyCode" children=[#<Nokogiri::XML::Text:0x3ff99a818764 "USD">]>, #<Nokogiri::XML::Element:0x3ff99a81c8a0 name="FormattedPrice" children=[#<Nokogiri::XML::Text:0x3ff99a81d534 "$28.99">]>]>, #<Nokogiri::XML::Element:0x3ff99a81ccb0 name="Manufacturer" children=[#<Nokogiri::XML::Text:0x3ff99a81c648 "Cambridge University Press">]>, #<Nokogiri::XML::Element:0x3ff99a81c2d8 name="NumberOfItems" children=[#<Nokogiri::XML::Text:0x3ff99a821cec "1">]>, #<Nokogiri::XML::Element:0x3ff99a821580 name="NumberOfPages" children=[#<Nokogiri::XML::Text:0x3ff99a82043c "194">]>, #<Nokogiri::XML::Element:0x3ff99a825bbc name="PackageDimensions" children=[#<Nokogiri::XML::Element:0x3ff99a824cd0 name="Height" attributes=[#<Nokogiri::XML::Attr:0x3ff99a824b68 name="Units" value="hundredths-inches">] children=[#<Nokogiri::XML::Text:0x3ff99a824168 "63">]>, #<Nokogiri::XML::Element:0x3ff99a829d98 name="Length" attributes=[#<Nokogiri::XML::Attr:0x3ff99a829d20 name="Units" value="hundredths-inches">] children=[#<Nokogiri::XML::Text:0x3ff99a828eac "890">]>, #<Nokogiri::XML::Element:0x3ff99a828c68 name="Weight" attributes=[#<Nokogiri::XML::Attr:0x3ff99a828b8c name="Units" value="hundredths-pounds">] children=[#<Nokogiri::XML::Text:0x3ff99a828074 "66">]>, #<Nokogiri::XML::Element:0x3ff9983f69d0 name="Width" attributes=[#<Nokogiri::XML::Attr:0x3ff9983f68f4 name="Units" value="hundredths-inches">] children=[#<Nokogiri::XML::Text:0x3ff997c6340c "598">]>]>, #<Nokogiri::XML::Element:0x3ff997c62cf0 name="ProductGroup" children=[#<Nokogiri::XML::Text:0x3ff997c623b8 "Book">]>, #<Nokogiri::XML::Element:0x3ff9961e1d2c name="ProductTypeName" children=[#<Nokogiri::XML::Text:0x3ff9961e0e40 "ABIS_BOOK">]>, #<Nokogiri::XML::Element:0x3ff9961e0508 name="PublicationDate" children=[#<Nokogiri::XML::Text:0x3ff9961e7b28 "2010-06-10">]>, #<Nokogiri::XML::Element:0x3ff9961e75c4 name="Publisher" children=[#<Nokogiri::XML::Text:0x3ff9961e727c "Cambridge University Press">]>, #<Nokogiri::XML::Element:0x3ff9961e70b0 name="SKU" children=[#<Nokogiri::XML::Text:0x3ff9961e6bc4 "Y9780521153348">]>, #<Nokogiri::XML::Element:0x3ff9961e682c name="Studio" children=[#<Nokogiri::XML::Text:0x3ff9961ebc64 "Cambridge University Press">]>, #<Nokogiri::XML::Element:0x3ff9961ea120 name="Title" children=[#<Nokogiri::XML::Text:0x3ff996f67ac8 "Turgot on Progress, Sociology and Economics: A Philosophical Review of the Successive Advances of the Human Mind on Universal History Reflections on ... in the History and Theory of Politics)">]>, #<Nokogiri::XML::Element:0x3ff996f676cc name="TradeInValue" children=[#<Nokogiri::XML::Element:0x3ff996f67028 name="Amount" children=[#<Nokogiri::XML::Text:0x3ff996f66ca4 "310">]>, #<Nokogiri::XML::Element:0x3ff996f669d4 name="CurrencyCode" children=[#<Nokogiri::XML::Text:0x3ff996f663a8 "USD">]>, #<Nokogiri::XML::Element:0x3ff996fadbb8 name="FormattedPrice" children=[#<Nokogiri::XML::Text:0x3ff996fad014 "$3.10">]>]>]>]>]>]>]>>

Answer 1

好吧，我明白了。我试图将 item_lookup 视为单个返回值，而不是返回搜索方式的哈希值。

item_lookup 与 item_search 基本相同:

res = Amazon::Ecs.item_lookup('9780521153348', :response_group => 'ItemAttributes', :id_type => 'ISBN', :search_index => 'Books')
  res.items.each do |item|
    puts item.get('ItemAttributes/TradeInValue/FormattedPrice')
  end