TypeError：无法将Nokogiri :: XML :: Attr转换为字符串

Question

我正在尝试抓取一些数据并找到或创建一个Rails对象，代码如下：

@books = @page.xpath(BOOKS_SELECTOR).map { |book| Book.find_or_create_by(name: book.attribute('title'))}

但是，当此代码运行时，我收到此错误：

  1) Error:
ScrapeHelperTest#test_scrape_page_test:
TypeError: can't cast Nokogiri::XML::Attr to string
    app/helpers/scrape_helper.rb:25:in `block in scrape'
    app/helpers/scrape_helper.rb:25:in `map'
    app/helpers/scrape_helper.rb:25:in `scrape'
    test/helpers/scrape_helper_test.rb:11:in `block in <class:ScrapeHelperTest>'

Answer 1

@books = @page.xpath(BOOKS_SELECTOR).map do |book| 
  Book.find_or_create_by(name: book['title'])
end

在节点上使用散列访问器[]将返回属性的值，而不是Nokogiri::XML::Attr返回的#attribute节点。