Question

i’ve written a function within a model to scrape a site and store certain attributes within a separate model (story):

def get_content   

          request = HTTParty.get("#{url}")

          doc = Nokogiri::HTML(request.body)

         doc.css("#{anchor}")["#{range}"].each do |entry|

            story = self.stories.new
            story.title = entry.text
            story.url = entry[:href]
            story.save

        end

This uses the url, anchor, and range attributes of a Sections variable. The range attribute is stored as an array range – i.e. 0..2 or 11..13 – however, I’m being told that it can’t convert a string into a variable. I’ve tried storing range as an integer and as a string, but both fail.

I realise I could input the beginning and end of the range as two separate integers in my db, and put ["#{beginrange}".."#{endrange}"] but this seems a messy way of doing it.

Any other ideas? Many thanks in advance

Answer 1

Hmm if you are sure that the range is always a string like ‘1..2‘ (‘<Integer >..<Integer>‘), you can use the eval method:

In my IRB console:

1.9.3p0 :032 > (eval "1..2").each { |l| puts l }
1
2
 => 1..2 
1.9.3p0 :033 > (eval "1..2").inspect
 => "1..2" 
1.9.3p0 :034 > (eval "1..2").class
 => Range

In your case:

doc.css("#{anchor}")[eval(range)].each do |entry|
  #...
end

But eval is kind of dangerous. If you are sure that the range attribute is a Range as a String (validations and Regex are here to help), you can use eval without risk.