Question

我需要找到两个使用ruby open-uri的网站之间的距离。使用

def check(url)
    site = open(url.base_url)
    link = %r{^<([a])([^"]+)*([^>]+)*(?:>(.*)<\/\1>|\s+\/>)$}
    site.each_line {|line| puts $&,$1,$2,$3,$4 if (line=~link)}
    p url.links
end

查找链接无法正常工作。有什么想法吗？

Answer 1

如果你想找到a标签＆＃39; href参数，使用正确的工具，这通常不是正则表达式。您更有可能使用HTML / XML解析器。

Nokogiri是Ruby的首选解析器：

require 'nokogiri'
require 'open-uri'

doc = Nokogiri.HTML(open('http://www.example.org/index.html'))
doc.search('a').map{ |a| a['href'] }

pp doc.search('a').map{ |a| a['href'] }
# => [
# =>  "/",
# =>  "/domains/",
# =>  "/numbers/",
# =>  "/protocols/",
# =>  "/about/",
# =>  "/go/rfc2606",
# =>  "/about/",
# =>  "/about/presentations/",
# =>  "/about/performance/",
# =>  "/reports/",
# =>  "/domains/",
# =>  "/domains/root/",
# =>  "/domains/int/",
# =>  "/domains/arpa/",
# =>  "/domains/idn-tables/",
# =>  "/protocols/",
# =>  "/numbers/",
# =>  "/abuse/",
# =>  "http://www.icann.org/",
# =>  "mailto:iana@iana.org?subject=General%20website%20feedback"
# => ]

Answer 2

我看到这个正则表达式有几个问题：

空格必须位于空标记中的尾部斜杠之前，但正则表达式需要它
您的正则表达式非常详细且冗余

请尝试以下操作，它会从＆lt; a＆gt;中提取您的网址。标记：

link = /<a \s   # Start of tag
    [^>]*       # Some whitespace, other attributes, ...
    href="      # Start of URL
    ([^"]*)     # The URL, everything up to the closing quote
    "           # The closing quotes
    /x          # We stop here, as regular expressions wouldn't be able to
                # correctly match nested tags anyway

用于在<a> open-uri ruby</a>中查找href的正则表达式

2 个答案: