检查NokogiriHTML文档是否可用-CheckifNokogiriHTMLdocumentisusable

4  

I'd start with something like:

我首先要说的是:

require 'nokogiri'
require 'open-uri'

begin
  doc = Nokogiri.HTML(open(url))
rescue Exception => e
  puts "Couldn't read \"#{ url }\": #{ e }"
  exit
end

puts (doc.errors.empty?) ? "No problems found" : doc.errors

Nokogiri sets the document's errors array to the values of any errors that occurred during the parsing process.

Nokogiri将文档的错误数组设置为解析过程中发生的任何错误的值。

This only addresses one part of the issue though. Malicious people like to break things, and this would be very easy to break. In general, be very careful about anything a user gives you, especially if your site is exposed to the wild internet.

这只解决了问题的一部分。恶意的人喜欢破坏东西，这很容易破坏。一般来说，对于用户提供给你的任何东西都要非常小心，特别是当你的站点暴露在狂野的互联网中时。

Prior to telling OpenURI to load the file to give to Nokogiri, you should sniff that URL and do some sanity checks using a HTTP HEAD request to find out the size and MIME-TYPE of the content being retrieved. Once you know those, you can try loading the file.

在告诉OpenURI加载文件以提供给Nokogiri之前，您应该先嗅探该URL并使用HTTP HEAD请求进行一些完整性检查，以找出要检索的内容的大小和mime类型。一旦知道了这些，就可以尝试加载文件。

3  

Firstly, it's bad style to 'rescue Exception => e' in Ruby. [Refer: http://daniel.fone.net.nz/blog/2013/05/28/why-you-should-never-rescue-exception-in-ruby/ ]

首先，在Ruby中“rescue Exception => e”是不好的风格。(参考:http://daniel.fone.net.nz/blog/2013/05/28/why-you-should-never-rescue-exception-in-ruby/)

Secondly, for this case, "rescue OpenURI::HTTPError => e" would be more suitable.

其次，对于这种情况，“save OpenURI: HTTPError => e”更合适。

1  

I'm not familiar with handling exceptions but something like :

我对处理异常不太熟悉，但是类似:

begin
  page = Nokogiri::HTML(open("http://example.com"))
ensure
  puts "not a document of any kind"
end
do_something_whith(page) if page

...should do the trick.

…应该足够了。

or (after reading your comment) :

或(在阅读你的评论后):

begin
  page = open("http://example.com")
ensure
  puts "not a document of any kind"
end
Nokogiri::HTML(page) if page