Rakefile: add cost target to generate cost estimate
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@ -8,6 +8,11 @@ Rakefile instead of Makefile for better text file parsing capabilities.
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=end
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require 'rake/clean'
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require 'csv' # to export BOM and costs
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require 'open-uri' # to parse URLs
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require 'open_uri_redirections' # allow redirections
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require 'net/http' # to get sites
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require 'nokogiri' # to parse sites
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require 'json' # to parse GET site responses
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# =================
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# project variables
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@ -113,6 +118,11 @@ boms = [ "#{name}.bom.csv" ]
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task :bom => boms
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CLOBBER.include(boms)
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desc "generate cost estimte"
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costs = [ "#{name}.cost.csv" ]
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task :cost => costs
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CLOBBER.include(costs)
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# ===============
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# file generation
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# ===============
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@ -193,6 +203,91 @@ rule ".bom.csv" => ".sch" do |t|
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end
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end
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desc "generate cost estimate from schematic"
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# this version uses Digi-Key, AliExpress, and LCSC
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# Digi-Key is easily scrapable, while Mouser isn't
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# Digi-Key is only one distributor, but the end prices across distributor is often similar
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rule ".cost.csv" => ".sch" do |t|
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puts "scraping distributor sites to get prices. this may take some time"
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sellers = ['digikey-id','aliexpress-id','lcsc-id'] # get seller SKU
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boards = [1, 10, 100] # calculate the price for as many boards
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total_price = Array.new(sellers.size){Array.new(boards.size, 0.0)} # total price for x boards
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unit_price = Array.new(sellers.size){Array.new(boards.size, 0.0)} # unit price for 1 board
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# get component information
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attributes = ["value","manufacturer","manufacturer-id"]+sellers # BOM fields to get
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parts = bom2(t.prerequisites[0], attributes) # get field values
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# put result in CVS
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CSV.open(t.name, "wb") do |csv|
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csv << ["refdes", "quantity", "manufacturer", "part number"] + (sellers.collect{|seller| [seller, "stock"] + boards.collect{|qty| ["unit price for #{qty} board(s)", "total price for #{qty} board(s)"]}}).flatten
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parts.each do |part|
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part['qty'] = part['qty'].to_i # converted quantity from BOM string to integer for later calculation
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line = [part['refdes'], part['qty'], part['manufacturer'], part['manufacturer-id']] # start CSV line
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sellers.each_index do |seller_i| # go through all seller
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seller = sellers[seller_i] # current seller
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if part[seller] and !part[seller].empty? then
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line << part[seller]
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price = case seller
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when 'aliexpress-id'
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scrape_aliexpress(part[seller])
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when 'digikey-id'
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nil
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when 'lcsc-id'
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scrape_lcsc(part[seller])
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else
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nil
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end
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if price then
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line << price[:stock]
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boards.each_index do |boards_i|
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quantity = boards[boards_i]
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# find lowest price (considering the quantity and quantity prices)
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unit = nil
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total = nil
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price[:prices].each do |p|
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if !unit or !total then
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unit = p[1].to_f
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total = [quantity, p[0].to_i].max * unit
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end
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if [quantity, p[0].to_i].max * p[1].to_f < total then
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unit = p[1].to_f
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total = [quantity, p[0].to_i].max * unit
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end
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end
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if "USD" == price[:currency] then
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unit = usd2eur(unit)
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total = usd2eur(total)
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end
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line << unit
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unit_price[seller_i][boards_i] += line[-1]
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line << total
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total_price[seller_i][boards_i] += line[-1]
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end
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else
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line += [nil] * (1 + boards.size * 2)
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end
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else
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line += [nil] * (2 + boards.size * 2)
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end # seller
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end # sellers
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csv << line
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end # parts
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# summary
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line = [nil] * 4
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sellers.each_index do |seller_i|
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line += [nil, nil]
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boards.each_index do |boards_i|
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line << unit_price[seller_i][boards_i]
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line << total_price[seller_i][boards_i]
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end
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end
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csv << line
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# details
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csv << []
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csv << ["all prices and stocks have been retrieved from Digikey, AliExpress, and LCSC on #{Time.now.to_s}"]
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csv << ["all prices are in EUR. prices originally in USD have been converted at a rate of #{usd2eur(1.0)}"]
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end # CSV file
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end # end cost file
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# ================
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# helper functions
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# ================
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@ -229,3 +324,108 @@ def bom2(schematic, attributes)
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return to_return
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end
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# convert USD $ value to EUR €
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def usd2eur(usd)
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return usd / eur2usd(1.0)
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end
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# convert EUR € value to USD $
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def eur2usd(eur)
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# get rate if we don't have already
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unless $eur2usd then
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url = "https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml"
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doc = Nokogiri::HTML(open(URI.escape(url), :allow_redirections => :all))
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$eur2usd = doc.xpath('//cube[@currency="USD"]')[0].attr('rate').to_f
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end
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return eur * $eur2usd
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end
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# get prices from LCSC using SKU
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def scrape_lcsc(sku)
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to_return = {stock: nil, currency: nil, prices: nil} # information to return (lot price, unit quantity, unit stock)
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# get page
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# the search page does not always list existing parts, instead it will try
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url = "https://lcsc.com/pre_search/link?type=lcsc&&value=#{sku}"
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puts "scraping #{url}" if $scrape_debug
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doc = Nokogiri::HTML(open(URI.escape(url),:allow_redirections => :all))
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# verify if we have got a product page
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if doc.xpath('//div[@id="product_details"]').empty? then
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puts "no product details:\n #{doc}" if $scrape_debug
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return nil
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end
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doc.xpath('//div[@id="product_details"]//div[contains(@class,"stock-number")]').each do |element|
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next unless element["data-stock"]
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to_return[:stock] = element["data-stock"]
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end
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to_return[:currency] = "USD" # we could verify in the price, but I'm lazy
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doc.xpath('//input[contains(@class,"salam-price")]').each do |element|
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next unless element["data-price"]
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to_return[:prices] = []
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element["data-price"].split("],[").each do |price|
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price.gsub!("[", "")
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price.gsub!("]", "")
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price = price.split(",")
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to_return[:prices] << [price[0].to_i, price[1].to_f]
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end
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end
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return to_return
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end
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# get prices from AliExpress using SKU
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def scrape_aliexpress(sku)
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to_return = {stock: nil, currency: nil, prices: nil} # information to return (lot price, unit quantity, unit stock)
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# get page
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url = "https://www.aliexpress.com/item/#{sku}.html"
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puts "scraping #{url}" if $scrape_debug
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doc = Nokogiri::HTML(open(URI.escape(url),:allow_redirections => :all))
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# all the values can be found in javascript variables (stock is even only there)
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js_docs = doc.xpath('//script')
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if js_docs.empty? then
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puts "script not found:\n#{doc}" if $scrape_debug
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return nil
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end
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js_json = nil
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js_docs.each do |js_doc|
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js_text = js_doc.text
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next unless js_text.include?("window.runParams = {")
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js_var = js_text.split('data: ')[1].split('csrfToken: ')[0].gsub(/,[\w\n]*$/, '')
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js_json = JSON.parse(js_var)
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end
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unless js_json and js_json["priceModule"] then
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puts "priceModule not found:\n#{js_json}" if $scrape_debug
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return nil
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end
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# get currency
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unless js_json["priceModule"]["formatedPrice"] then
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puts "currency not found:\n#{js_json['priceModule']}" if $scrape_debug
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return nil
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end
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if js_json["priceModule"]["formatedPrice"].start_with? "US" then
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to_return[:currency] = "USD"
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elsif js_json["priceModule"]["formatedPrice"].start_with? "EU" then
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to_return[:currency] = "EUR"
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end
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# get quantity
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unless js_json["quantityModule"] and js_json["quantityModule"]["totalAvailQuantity"] then
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puts "quantityModule not found:\n#{js_json}" if $scrape_debug
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return nil
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end
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to_return[:stock] = js_json["quantityModule"]["totalAvailQuantity"]
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# get price
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unless js_json["priceModule"]["numberPerLot"] and (js_json["priceModule"]["formatedActivityPrice"] or js_json["priceModule"]["formatedPrice"] ) then
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puts "priceModule malformatted:\n#{js_json['priceModule']}" if $scrape_debug
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return nil
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end
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to_return[:prices] = []
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lot = js_json["priceModule"]["numberPerLot"].to_i
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price = js_json["priceModule"]["formatedActivityPrice"] || js_json["priceModule"]["formatedPrice"]
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unless price then
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puts "priceModule malformatted:\n#{js_json['priceModule']}" if $scrape_debug
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return nil
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end
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price = price.split('$')[1].to_f
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to_return[:prices] << [ lot, price / lot ]
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return to_return
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end
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