How to refresh a large database?

Question

I built a rake task to donwload a zip from Awin datafeed and import it to my product model via activerecord-import.

require 'zip'
require 'httparty'
require 'active_record'
require 'activerecord-import'

namespace :affiliate_datafeed do
    desc "Import products data from Awin"
    task import_product_awin: :environment do
        url = "https://productdata.awin.com"
        dir = "db/affiliate_datafeed/awin.zip"

        File.open(dir, "wb") do |f| 
            f.write HTTParty.get(url).body
        end

        zip_file = Zip::File.open(dir)
        entry = zip_file.glob('*.csv').first
        csv_text = entry.get_input_stream.read
        products = []

        CSV.parse(csv_text, :headers=>true).each do |row|
            products << Product.new(row.to_h)
        end
        Product.import(products)
  end
end

How to update the product db only if the product doesn't exist or if there is a new date in the last_updated field? What is the best way to refresh a large db?

Answer 1

Probably use some methods like the following to keep checking the last_updated or last_modified header field in your rake task.

def get_date
  date = CSV.foreach('CSV_raw.csv', :headers => false).first { |r| puts r}
  $last_modified = Date.parse(date.compact[1]) # if last_updated is first row of CSV or use your http req header
end

run_once = ARGV.length > 0 # to run once & test if it works; not sure if rake taks accept args.
if not run_once
  puts "Daemon Mode"
end

if not File.read('last_update.txt').empty?
  date_in_file = Date.parse(File.read('last_update.txt'))
else
  date_in_file = Date.parse('2001-02-03')
end
if $last_modified > date_in_file
  "your db updating method"
end
unless run_once
  sleep UPDATE_INTERVAL # whatever value you want for the interval to be
end
end until run_once