Question

I’m writing a website in Rails and I need to reed a RSS feed. The script works as intended, but I just got an error indicating that the source could not be read.

This is the script:

def setup_feed
  source = "http://path_to_feed/"
  content = "" # raw content of rss feed will be loaded here

  open(source) do |s|
    content = s.read
  end
  @rss = RSS::Parser.parse(content, false)
end

My concern is that the site will produce an error or just “crash” if the source isn’t available for whatever reasons. How can I protect myself against this?

This is the exact error:

Errno::ENOENT in WelcomeController#index

No such file or directory - http://path_to_feed/

Answer 1

EDIT
Found a more recent link: http://binarysoul.com/blog/rails-3-url-validation by Eric Himmelreich

class Example
  include ActiveModel::Validations

  ##
  # Validates a URL
  #
  # If the URI library can parse the value, and the scheme is valid
  # then we assume the url is valid
  #
  class UrlValidator < ActiveModel::EachValidator
    def validate_each(record, attribute, value)
      begin
        uri = Addressable::URI.parse(value)

        if !["http","https","ftp"].include?(uri.scheme)
          raise Addressable::URI::InvalidURIError
        end
      rescue Addressable::URI::InvalidURIError
        record.errors[attribute] << "Invalid URL"
      end
    end
  end

  validates :field, :url => true
end