parse_har_file.rb

require 'json'
require 'uri'

# how to use:
# ruby parse_har_file.rb filename_in_curr_dir pattern_to_match_correct_urls optional_param_accepted_statuses_separated_by_commas

filename        = ARGV[0]
match_pattern   = Regexp.compile(ARGV[1] || "")
accept_statuses = (ARGV[2] || "").split(',').map(&:to_i)


json = JSON.parse File.read(filename)
urls = json.dig('log', 'entries')
           .select { |e| accept_statuses.empty? || accept_statuses.include?(e.dig('response', 'status')) }
           .map { |e| e.dig 'request', 'url' }
           .select { |u| u =~ match_pattern }
           .map { |e| URI.decode e }
puts urls