How to scrape data from list of URLs and save data to CSV with nokogiri - ruby

Question

I have a file called bontyurls.csv that looks like this:
http://bontrager.com/model/11383
http://bontrager.com/model/01740
http://bontrager.com/model/09595
I want my script to read that file and then spit out a file like this: bonty_test_urls_results.csv
url,model_names
http://bontrager.com/model/11383,"Road TLR Conversion Kit"
http://bontrager.com/model/01740,"404 File Not Found"
http://bontrager.com/model/09595,"RXL Road"
Here's what I've got so far:
# based on code from here: http://www.andrewsturges.com/2011/09/how-to-harvest-web-data-using-ruby-and.html
require 'nokogiri'
require 'open-uri'
require 'csv'
#urls = Array.new
#model_names = Array.new
urls = CSV.read("bontyurls.csv")
(0..urls.length - 1).each do |index|
puts urls[index][0]
doc = Nokogiri::HTML(open(urls[index][0]))
doc.xpath('//h1').each do |model_name|
#model_name << model_name.content
end
end
# write results to file
CSV.open("bonty_test_urls_results.csv", "wb") do |row|
row << ["url", "model_names"]
(0..#urls.length - 1).each do |index|
row << [
#urls[index],
#model_names[index]]
end
end
That code isn't working. I'm getting this error:
$ ruby bonty_test_urls.rb
http://bontrager.com/model/00310
bonty_test_urls.rb:15:in `block (2 levels) in <main>': undefined method `<<' for nil:NilClass (NoMethodError)
from /home/simon/.rvm/gems/ruby-1.9.3-p194/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:239:in `block in each'
from /home/simon/.rvm/gems/ruby-1.9.3-p194/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:238:in `upto'
from /home/simon/.rvm/gems/ruby-1.9.3-p194/gems/nokogiri-1.5.5/lib/nokogiri/xml/node_set.rb:238:in `each'
from bonty_test_urls.rb:14:in `block in <main>'
from bonty_test_urls.rb:11:in `each'
from bonty_test_urls.rb:11:in `<main>'
Here is some code that returns the model_name at least. I'm just having trouble getting it to work in the larger script:
require 'open-uri'
require 'nokogiri'
doc = Nokogiri::HTML(open("http://bontrager.com/model/09124"))
doc.xpath('//h1').each do |node|
puts node.text
end
Also, I haven't figured out how to handle the URLs that return a 404.

Answer 1

This is how I'd do it:
require 'csv'
require 'nokogiri'
require 'open-uri'
CSV_OPTIONS = {
:write_headers => true,
:headers => %w[url model_names]
}
CSV.open('bonty_test_urls_results.csv', 'wb', CSV_OPTIONS) do |csv|
csv_doc = File.foreach('bontyurls.csv') do |url|
url.chomp!
begin
doc = Nokogiri.HTML(open(url))
h1 = doc.at('h1').text.strip
h1 = doc.at('title').text.strip.sub(/^Bontrager: /i, '') if (h1.empty?)
csv << [url, h1]
rescue OpenURI::HTTPError => e
csv << [url, e.message]
end
end
end
Which generates a CSV file like:
url,model_names
http://bontrager.com/model/11383,Road TLR Conversion Kit (Model #11383)
http://bontrager.com/model/01740,404 File Not Found
http://bontrager.com/model/09595,RXL Road (Model #09595)

Answer 2

You declare #model_names, but try to push in to #model_name, which is why it's nil.