How to Tail the STEEM Blockchain in Ruby

Ever want to just watch the blockchain from a terminal, as if you're tailing a log file? Here's how to do that in ruby.

As always, we use Radiator with bundler. You can get bundler with this command:

$ gem install bundler

I've tested it on various versions of ruby. The oldest one I got it to work was:

ruby 2.0.0p645 (2015-04-13 revision 50299) [x86_64-darwin14.4.0]

First, make a project folder:

$ mkdir radiator
$ cd radiator

Create a file named Gemfile containing:

source 'https://rubygems.org'
gem 'radiator', github: 'inertia186/radiator'
gem 'awesome_print'

Then run the command:

$ bundle install

Create a file named tail_blockchain.rb containing:

require 'rubygems'
require 'bundler/setup'

Bundler.require

stream = Radiator::Stream.new
last_op = nil
pattern = ARGV.first

stream.operations do |operation|
  if !!pattern
    next unless operation.inspect =~ /#{pattern}/i
  end
  op_key = operation.keys.first
  op_value = operation.values.first
  log = []

  case op_key
  when :comment
    (v = op_value.title).empty? or log << "title: #{v}"
    (v = op_value.parent_author).empty? or log << "parent_author: #{v}"
    (v = op_value.parent_permlink).empty? or log << "parent_permlink: #{v}"
    log << "author: #{op_value.author}"
    log << "permlink: #{op_value.permlink}"
  when :vote
    log << "weight: #{op_value.weight / 100} %"
    log << "voter: #{op_value.voter}"
    log << "author: #{op_value.author}, permlink: #{op_value.permlink}"
  when :custom_json
    log << "id: #{op_value.id}"
    log << "json: #{op_value.json}"
  when :transfer
    log << "from: #{op_value.from}"
    log << "to: #{op_value.to}"
    log << "amount: #{op_value.amount}"
    (v = op_value.memo).empty? or log << "memo: #{v}"
  else log << op_value.to_json
  end

  ap op_key if last_op != op_key
  ap log.join(', ')
  last_op = op_key
end

Then run it:

$ ruby tail_blockchain.rb

You can also pass along a regex pattern to match on:

$ ruby tail_blockchain.rb ned

Note, the comment operation (which also represents posts) does not output the body. If the operation, including the body, contains the optional regex, it will display that line without the body so it doesn't flood the display.

ruby