Hive Developers logo

Hive Developer Portal

Stream Blockchain Transactions

How to stream transactions and operations from Hive blockchain.

Full, runnable src of Stream Blockchain Transactions can be downloaded as part of: tutorials/ruby (or download just this tutorial: devportal-master-tutorials-ruby-13_stream_blockchain_transactions.zip).

To respond to live activity on the blockchain, a common approach is to make a request for the current block number, access all of the information in that block, and repeat. Many API clients have dedicated tools for simplifying this process. In Radiator, this tool is part of the Radiator::Stream class. In addition, Radiator will allow you to specify exactly what type of operation you’re interested in.

Also see:

Sections

  1. Streaming Transactions
  2. Streaming Operations
  3. To Run - Running the example.

Streaming Transactions

stream_blockchain_transactions.rb

In the example script, we can stream transactions with the following arguments:

ruby stream_blockchain_transactions.rb head transactions

This will instruct the script to follow transactions at head block_num instead of irreversible.

See: head_block_number vs. last_irreversible_block_num

This is done by using the following ruby:

stream.transactions(*args) do |trx|
  puts JSON.pretty_generate trx
end

The args variable contains the start (block_num to start from) and mode (head or irreversible).

Streaming Operations

In the example script, we can also pass the following arguments:

ruby stream_blockchain_transactions.rb head ops comment

This will instruct the script to follow the blockchain at head block_num instead of irreversible. It will stream operations, with the type of comment.

The script will allow multiple operation types:

ruby stream_blockchain_transactions.rb head ops comment vote

Virtual operations are also allowed, but make sure to pass irreversible instead of head:

ruby stream_blockchain_transactions.rb irreversible ops producer_reward author_reward

Or, if you pass no operation types, the script will stream all types:

ruby stream_blockchain_transactions.rb head ops

This is done by using the following ruby:

stream.operations(type, *args) do |op|
  puts op.to_json
end

The type variable can be nil or the type of ops we’re looking for whereas args contains the start (block_num to start from) and mode (head or irreversible).

Final code:

require 'rubygems'
require 'bundler/setup'

Bundler.require

mode = (ARGV[0] || 'irreversible').to_sym
what = (ARGV[1] || 'ops').to_sym
type = (ARGV[2..-1] || ['vote']).map(&:to_sym)
stream = Radiator::Stream.new

# Set to a block number you would like to begin streaming from, or leave nil
# to stream from the latest block.
start = nil
args = [start, mode]

case what
when :blocks
  stream.blocks(*args) do |block|
    block_num = block.block_id[0..7].hex
    print "block_num: #{block_num}"
    puts "; block_id: #{block.block_id}"
    print "\ttransactions: #{block.transactions.size}"
    print "; witness: #{block.witness}"
    puts "; timestamp: #{block.timestamp}"
  end
when :transactions
  stream.transactions(*args) do |trx|
    puts JSON.pretty_generate trx
  end
when :ops
  stream.operations(type, *args) do |op|
    puts op.to_json
  end
end

To Run

First, set up your workstation using the steps provided in Getting Started. Then you can create and execute the script (or clone from this repository):

git clone https://gitlab.syncad.com/hive/devportal.git
cd devportal/tutorials/ruby/13_stream_blockchain_transactions
bundle install
ruby stream_blockchain_transactions.rb

Example Output

{"voter":"piggypet","author":"tanama","permlink":"daily-2018-9-12","weight":10000}
{"voter":"votes4minnows","author":"askquestion","permlink":"latest-bitcoin-price-and-news-update-13-09-2018","weight":250}
{"voter":"vncedora2018","author":"adncabrera","permlink":"nicomedescuentalacadadelreytanospoema-98jxnjsjzu","weight":10000}
{"voter":"baimatjeh81","author":"albertvhons","permlink":"promoting-steemit-post-via-proof-of-participation-pop","weight":10000}
{"voter":"steemulator","author":"bonanza-kreep","permlink":"communicate-and-travel-with-alfa-enzo-new-social-network","weight":10000}
{"voter":"kernigeetrueset","author":"haejin","permlink":"vitamin-shoppe-vsi-analysis","weight":10000}
{"voter":"borrowedearth","author":"rijalmahyud","permlink":"this-is-my-job","weight":10000}
{"voter":"renatdag","author":"algarion","permlink":"cards-3-1536663927","weight":10000}
{"voter":"elieserurabno","author":"cathyhaack","permlink":"my-introduction-hello-word-of-steemit","weight":10000}
{"voter":"jmotip","author":"glennolua","permlink":"btc-chart-review-sept-12-20-00-pst","weight":10000}
{"voter":"bishalacharya","author":"barber78","permlink":"beautiful-cloudformations","weight":10000}
{"voter":"ivan174","author":"securixio","permlink":"cloud-mining-is-no-longer-profitable","weight":10000}
{"voter":"admiralbot","author":"homsys","permlink":"rare-photo-picture-698-105","weight":-10000}
Back to top