Ruby/Rails - 无法获取数组的大小

Question

我正在使用以下代码使用 scrAPI gem 来抓取 eBay 列表：

我通过执行安装了它：

gem install scrapi

我还通过声明覆盖了它的默认文本解析器：

Scraper::Base.parser :html_parser

问题是我不断在 上收到以下错误拍卖数组大小。不确定我做错了什么？ size 和 length 都不起作用。

Scraper.rb:31:in `<class:ScraperDemo>': undefined method `size' for nil:NilClass (No
MethodError)Scraper.rb:10:in `<main>'

我只是通过命令行运行：

ruby Scraper.rb

代码：

#!/usr/bin/env ruby

require 'open-uri'
require 'httparty'
require 'json'
require 'scrapi'

Scraper::Base.parser :html_parser

class ScraperDemo

    ebay_auction = Scraper.define do
        process "h3.ens>a", :description=>:text, :url=>"@href"
        process "td.ebcPr>span", :price=>:text
        process "div.ebPicture >a>img", :image=>"@src"

        result :description, :url, :price, :image
    end

    ebay = Scraper.define do
        array :auctions

        process "table.ebItemlist tr.single", :auctions=>ebay_auction

        result :auctions
    end

    auctions = ebay.scrape(URI.parse('http://search.ebay.com/ipod-nano_W0QQcatrefZC6QQfromZR3QQfsooZ1QQfsopZ1QQkeywordZonQQsacatZQ2d1QQstrkwZipod'))

    # No. of channels found
    puts auctions.size # error occurs on this line number

    # First auction:
    auction = auctions[0]
    puts auction.description
    puts auction.url

end

Answer 1

我最终选择使用 Nokogiri 作为我的刮刀。