Nokogiri, open-uri, and Unicode Characters

问题:

I'm using Nokogiri and open-uri to grab the contents of the title tag on a webpage, but am having trouble with accented characters. What's the best way to deal with these? Here's what I'm doing:

require 'open-uri'
require 'nokogiri'

doc = Nokogiri::HTML(open(link))
title = doc.at_css("title")

At this point, the title looks like this:

Rag\303\271

Instead of:

Ragù

How can I have nokogiri return the proper character (e.g. ù in this case)?

Here's an example URL:

http://www.epicurious.com/recipes/food/views/Tagliatelle-with-Duck-Ragu-242037

回答1:

When you say "looks like this," are you viewing this value IRB? It's going to escape non-ASCII range characters with C-style escaping of the byte sequences that represent the characters.

If you print them with puts, you'll get them back as you expect, presuming your shell console is using the same encoding as the string in question (Apparently UTF-8 in this case, based on the two bytes returned for that character). If you are storing the values in a text file, printing to a handle should also result in UTF-8 sequences.

If you need to translate between UTF-8 and other encodings, the specifics depend on whether you're in Ruby 1.9 or 1.8.6.

For 1.9: http://blog.grayproductions.net/articles/ruby_19s_string for 1.8, you probably need to look at Iconv.

Also, if you need to interact with COM components in Windows, you'll need to tell ruby to use the correct encoding with something like the following:

require 'win32ole'

WIN32OLE.codepage = WIN32OLE::CP_UTF8

If you're interacting with mysql, you'll need to set the collation on the table to one that supports the encoding that you're working with. In general, it's best to set the collation to UTF-8, even if some of your content is coming back in other encodings; you'll just need to convert as necessary.

Nokogiri has some features for dealing with different encodings (probably through Iconv), but I'm a little out of practice with that, so I'll leave explanation of that to someone else.

回答2:

Summary: When feeding UTF-8 to Nokogiri through open-uri, use open(...).read and pass the resulting string to Nokogiri.

Analysis: If I fetch the page using curl, the headers properly show Content-Type: text/html; charset=UTF-8 and the file content includes valid UTF-8, e.g. "Genealogía de Jesucristo". But even with a magic comment on the Ruby file and setting the doc encoding, it's no good:

# encoding: UTF-8
require 'nokogiri'
require 'open-uri'

doc = Nokogiri::HTML(open('http://www.biblegateway.com/passage/?search=Mateo1-2&version=NVI'))
doc.encoding = 'utf-8'
h52 = doc.css('h5')[1]
puts h52.text, h52.text.encoding
#=> Genealogà a de Jesucristo
#=> UTF-8

We can see that this is not the fault of open-uri:

html = open('http://www.biblegateway.com/passage/?search=Mateo1-2&version=NVI')
gene = html.read[/Gene\S+/]
puts gene, gene.encoding
#=> Genealogía
#=> UTF-8

This is a Nokogiri issue when dealing with open-uri, it seems. This can be worked around by passing the HTML as a raw string to Nokogiri:

# encoding: UTF-8
require 'nokogiri'
require 'open-uri'

html = open('http://www.biblegateway.com/passage/?search=Mateo1-2&version=NVI')
doc = Nokogiri::HTML(html.read)
doc.encoding = 'utf-8'
h52 = doc.css('h5')[1].text
puts h52, h52.encoding, h52 == "Genealogía de Jesucristo"
#=> Genealogía de Jesucristo
#=> UTF-8
#=> true

回答3:

I was having the same problem and the Iconv approach wasn't working. Nokogiri::HTML is an alias to Nokogiri::HTML.parse(thing, url, encoding, options).

So, you just need to do:

doc = Nokogiri::HTML(open(link).read, nil, 'utf-8')

and it'll convert the page encoding properly to utf-8. You'll see Ragù instead of Rag\303\271.

回答4:

Try setting the encoding option of Nokogiri, like so:

require 'open-uri'
require 'nokogiri'
doc = Nokogiri::HTML(open(link))
doc.encoding = 'utf-8'
title = doc.at_css("title")

回答5:

You need to convert the response from the website being scraped (here epicurious.com) into utf-8 encoding.

as per the html content from the page being scraped, its "ISO-8859-1" for now. So, you need to do something like this:

require 'iconv'
doc = Nokogiri::HTML(Iconv.conv('utf-8//IGNORE', 'ISO-8859-1', open(link).read))

Read more about it here: http://www.quarkruby.com/2009/9/22/rails-utf-8-and-html-screen-scraping

回答6:

Just to add a cross-reference, this SO page gives some related information:

How to make Nokogiri transparently return un/encoded Html entities untouched?

回答7:

Tip: you could also use the Scrapifier gem to get metadata, as the page title, from URIs in a very simple way. The data are all encoded in UTF-8.

Check it out: https://github.com/tiagopog/scrapifier

Hope it's useful for you.

回答8:

Changing Nokogiri::HTML(...) to Nokogiri::HTML5(...) fixed issues I was having with parsing certain special character, specifically em-dashes.

(The accented characters in your link came through fine in both, so don't know if this would help you with that.)

EXAMPLE:

url = 'https://www.youtube.com/watch?v=4r6gr7uytQA'

doc = Nokogiri::HTML(open(url))
doc.title
=> "Josh Waitzkin â\u0080\u0094 How to Cram 2 Months of Learning into 1 Day | The Tim Ferriss Show - YouTube"

doc = Nokogiri::HTML5(open(url))
doc.title
=> "Josh Waitzkin — How to Cram 2 Months of Learning into 1 Day | The Tim Ferriss Show - YouTube"