Redis Pubsub test with backlog of posted messages.

Gemfile

Encoding.default_external = Encoding::UTF_8
Encoding.default_internal = Encoding::UTF_8

source 'https://rubygems.org'

gem 'redis'
gem "hiredis"
gem "em-synchrony"
gem 'json'

pub.rb

require 'bundler/setup'
require 'redis'
require 'json'

redis = Redis.new
channel = 'redis-pubsub-chat'
log = channel+'-log'

loop do
  msg = STDIN.gets
  if msg.strip != ""
    msg = msg.strip
    redis.publish channel, msg

    now = Time.now.utc
    timestamp = "#{now.to_i}#{now.nsec}"

    redis.zadd log, timestamp, msg
  end

end

sub.rb

require 'bundler/setup'
require 'redis'
require 'json'

redis = Redis.new(timeout: 0)
channel = 'redis-pubsub-chat'
log = channel+'-log'


old_data = redis.zrevrange(log, 0, -1)
old_data.each do |msg|
  puts msg
end

redis.subscribe(channel) do |on|
  on.message do |ch, msg|
    puts msg
  end
end