Adds email,name from a csv file to a new Sendgrid recipient list. Only emails that are not already on an existing recipient list are added to the new one.

add_sendgrid_recipient_list_with_non_duplicates.rb

require 'CSV'
require 'rest_client'
require 'json'

USERNAME=""
PASSWORD=""
URL_POSTFIX = "&api_user=#{USERNAME}&api_key=#{PASSWORD}"
SOURCE_LIST=""
NEW_LIST=""
CSV_FILE=""


def fetch_existing_list
  get_list_url = "https://sendgrid.com/api/newsletter/lists/email/get.json?list=#{SOURCE_LIST}"
  response = RestClient.get(get_list_url+URL_POSTFIX)
  JSON.parse(response)
end


def parse_csv
  result = []
  CSV.foreach(CSV_FILE, encoding: "ISO-8859-1") do |row|
    result << {'email' => row[0], 'name' => row[1]}
  end

  result
end

def mail_addresses_from_subscribers(subscribers)
  emails = []
  subscribers.each do |sub|
    emails << sub['email']
  end

  emails
end

def add_to_mailinglist(subscriber)
  add_subscriber_url = "https://sendgrid.com/api/newsletter/lists/email/add.json?list=#{NEW_LIST}&"
  data = "data="+subscriber.to_json
  url = add_subscriber_url+"&"+URI.encode(data)+URL_POSTFIX

  response = RestClient.get(url)
  puts "Adding subscriber: #{subscriber[:email]}: #{response.to_s}"
  puts "Result of adding sendgrid subscribers: #{response.to_s}"
end

def add_if_missing(emails, subscribers)
  subscribers.each do |sub|
    unless emails.include?(sub['email'])
      add_to_mailinglist(sub)
    end
  end
end


existing_subscribers = fetch_existing_list
imported_subscribers = parse_csv
existing_emails = mail_addresses_from_subscribers(existing_subscribers)
add_if_missing(existing_emails, imported_subscribers)