corte.rb

require 'nokogiri'
require 'open-uri'

Encoding.default_external = 'UTF-8'
query = params['query'] || 'banana'
page = (params['page'] || 0).to_i

MAX_ATTEMPTS = 10
attempts = 0
doc = nil

url = "https://www.elcorteingles.pt/supermercado/pesquisar/" + (page > 0 ? "#{page}" : "") + "?term=#{query}&search=text"

begin
  doc = Nokogiri::HTML(open(url).read.strip)
rescue Exception => ex
  puts "Error: #{ex}"
  attempts += 1
  retry if attempts < MAX_ATTEMPTS
end

if doc.nil?
  puts "Scrape failed repeatedly"
  # Do something about the persistent error
  # so that you don't try to access a nil
  # doc later on.
else
  puts "Scrape successful"
  # Do something with the scraped data
end