Blockchain Lite (Ruby Edition)
blockchain-lite library / gem - build your own blockchain with crypto hashes - revolutionize the world with blockchains, blockchains, blockchains one block at a time
- home :: github.com/openblockchains/blockchain.lite.rb
- bugs :: github.com/openblockchains/blockchain.lite.rb/issues
- gem :: rubygems.org/gems/blockchain-lite
- rdoc :: rubydoc.info/gems/blockchain-lite
What's a Blockchain?
A blockchain is a distributed database with a list (that is, chain) of records (that is, blocks) linked and secured by digital fingerprints (that is, crypto hashes).
See the Awesome Blockchains page for more.
Usage
Let's get started. Build your own blockchain one block at a time. Example:
require 'blockchain-lite'
b0 = Block.first( 'Genesis' )
b1 = Block.next( b0, 'Transaction Data...' )
b2 = Block.next( b1, 'Transaction Data...' )
b3 = Block.next( b2, 'Transaction Data...' )
blockchain = [b0, b1, b2, b3]
pp blockchain
will pretty print (pp) something like:
[#<Block:0x1eed2a0
@index = 0,
@timestamp = 2017-09-15 20:52:38,
@transactions_count = 1,
@transactions = ["Genesis"],
@previous_hash = "0",
@hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b">,
#<Block:0x1eec9a0
@index = 1,
@timestamp = 2017-09-15 21:02:38,
@transactions_count = 1,
@transactions = ["Transaction Data..."],
@hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743",
@previous_hash = "edbd4e11e69bc399a9ccd8faaea44fb27410fe8e3023bb9462450a0a9c4caa1b">,
#<Block:0x1eec838
@index = 2,
@timestamp = 2017-09-15 21:12:38,
@transactions_count = 1,
@transactions = ["Transaction Data..."],
@hash = "be50017ee4bbcb33844b3dc2b7c4e476d46569b5df5762d14ceba9355f0a85f4",
@previous_hash = "eb8ecbf6d5870763ae246e37539d82e37052cb32f88bb8c59971f9978e437743">,
#<Block:0x1eec6d0
@index = 3,
@timestamp = 2017-09-15 21:22:38
@transactions_count = 1,
@transactions = ["Transaction Data..."],
@hash = "5ee2981606328abfe0c3b1171440f0df746c1e1f8b3b56c351727f7da7ae5d8d",
@previous_hash = "be50017ee4bbcb33844b3dc2b7c4e476d46569b5df5762d14ceba9355f0a85f4">]
Blocks
Supported block types / classes for now include:
Basic
class Block
attr_reader :index
attr_reader :timestamp
attr_reader :transactions_count
attr_reader :transactions
attr_reader :previous_hash
attr_reader :hash
def initialize(index, transactions, previous_hash)
@index = index
@timestamp = Time.now.utc ## note: use coordinated universal time (utc)
@transactions = transactions
@transactions_count = transactions.size
@previous_hash = previous_hash
@hash = calc_hash
end
def calc_hash
sha = Digest::SHA256.new
sha.update( @timestamp.to_s +
@transactions.to_s +
@previous_hash )
sha.hexdigest
end
...
end
(Source: basic/block.rb)
Proof-of-Work
class Block
attr_reader :index
attr_reader :timestamp
attr_reader :transactions_count
attr_reader :transactions
attr_reader :transactions_hash ## merkle_root
attr_reader :previous_hash
attr_reader :nonce ## proof of work if hash starts with leading zeros (00)
attr_reader :hash
def initialize(index, transactions, previous_hash)
@index = index
@timestamp = Time.now.utc ## note: use coordinated universal time (utc)
@transactions = transactions
@transactions_count = transactions.size
@transactions_hash = MerkleTree.compute_root_for( transactions )
@previous_hash = previous_hash
@nonce, @hash = compute_hash_with_proof_of_work
end
def calc_hash
sha = Digest::SHA256.new
sha.update( @nonce.to_s +
@timestamp.to_s +
@transactions_hash +
@previous_hash )
sha.hexdigest
end
...
end
(Source: proof_of_work/block.rb)
Blockchain Helper / Convenience Wrapper
The Blockchain class offers some convenience helpers
for building and checking blockchains. Example:
b = Blockchain.new # note: will (auto-) add the first (genesis) block
b << 'Transaction Data...'
b << 'Transaction Data...'
b << 'Transaction Data...'
pp b
Check for broken chain links. Example:
b.broken?
# => false ## blockchain OK
or use the Blockchain class as a wrapper (pass in the blockchain array):
b0 = Block.first( 'Genesis' )
b1 = Block.next( b0, 'Transaction Data...' )
b2 = Block.next( b1, 'Transaction Data...' )
b3 = Block.next( b2, 'Transaction Data...' )
blockchain = [b0, b1, b2, b3]
b = Blockchain.new( blockchain )
b.broken?
# => false ## blockchain OK
and so on.
Transactions
Let's put the transactions from the (hyper) ledger book from Tulips on the Blockchain! on the blockchain:
| From | To | What | Qty |
|---|---|---|---|
| Dutchgrown (†) | Vincent | Tulip Bloemendaal Sunset | 10 |
| Keukenhof (†) | Anne | Tulip Semper Augustus | 7 |
| Flowers (†) | Ruben | Tulip Admiral van Eijck | 5 |
| Vicent | Anne | Tulip Bloemendaal Sunset | 3 |
| Anne | Julia | Tulip Semper Augustus | 1 |
| Julia | Luuk | Tulip Semper Augustus | 1 |
| Bloom & Blossom (†) | Daisy | Tulip Admiral of Admirals | 8 |
| Vincent | Max | Tulip Bloemendaal Sunset | 2 |
| Anne | Martijn | Tulip Semper Augustus | 2 |
| Ruben | Julia | Tulip Admiral van Eijck | 2 |
| Teleflora (†) | Max | Tulip Red Impression | 11 |
| Anne | Naomi | Tulip Bloemendaal Sunset | 1 |
| Daisy | Vincent | Tulip Admiral of Admirals | 3 |
| Julia | Mina | Tulip Admiral van Eijck | 1 |
(†): Grower Transaction - New Tulips on the Market!
b0 = Block.first(
{ from: "Dutchgrown", to: "Vincent", what: "Tulip Bloemendaal Sunset", qty: 10 },
{ from: "Keukenhof", to: "Anne", what: "Tulip Semper Augustus", qty: 7 } )
b1 = Block.next( b0,
{ from: "Flowers", to: "Ruben", what: "Tulip Admiral van Eijck", qty: 5 },
{ from: "Vicent", to: "Anne", what: "Tulip Bloemendaal Sunset", qty: 3 },
{ from: "Anne", to: "Julia", what: "Tulip Semper Augustus", qty: 1 },
{ from: "Julia", to: "Luuk", what: "Tulip Semper Augustus", qty: 1 } )
b2 = Block.next( b1,
{ from: "Bloom & Blossom", to: "Daisy", what: "Tulip Admiral of Admirals", qty: 8 },
{ from: "Vincent", to: "Max", what: "Tulip Bloemendaal Sunset", qty: 2 },
{ from: "Anne", to: "Martijn", what: "Tulip Semper Augustus", qty: 2 },
{ from: "Ruben", to: "Julia", what: "Tulip Admiral van Eijck", qty: 2 } )
...
resulting in:
[#<Block:0x2da3da0
@index = 0,
@timestamp = 1637-09-24 11:40:15,
@previous_hash = "0",
@hash = "32bd169baebba0b70491b748329ab631c85175be15e1672f924ca174f628cb66",
@transactions_count = 2,
@transactions =
[{:from=>"Dutchgrown", :to=>"Vincent", :what=>"Tulip Bloemendaal Sunset", :qty=>10},
{:from=>"Keukenhof", :to=>"Anne", :what=>"Tulip Semper Augustus", :qty=>7}]>,
#<Block:0x2da2ff0
@index = 1,
@timestamp = 1637-09-24 11:50:15,
@previous_hash = "32bd169baebba0b70491b748329ab631c85175be15e1672f924ca174f628cb66",
@hash = "57b519a8903e45348ac8a739c788815e2bd90423663957f87e276307f77f1028",
@transactions_count = 4,
@transactions =
[{:from=>"Flowers", :to=>"Ruben", :what=>"Tulip Admiral van Eijck", :qty=>5},
{:from=>"Vicent", :to=>"Anne", :what=>"Tulip Bloemendaal Sunset", :qty=>3},
{:from=>"Anne", :to=>"Julia", :what=>"Tulip Semper Augustus", :qty=>1},
{:from=>"Julia", :to=>"Luuk", :what=>"Tulip Semper Augustus", :qty=>1}]>,
#<Block:0x2da2720
@index = 2,
@timestamp = 1637-09-24 12:00:15,
@previous_hash = "57b519a8903e45348ac8a739c788815e2bd90423663957f87e276307f77f1028",
@hash = "ec7dd5ea86ab966d4d4db182abb7aa93c7e5f63857476e6301e7e38cebf36568",
@transactions_count = 4,
@transactions =
[{:from=>"Bloom & Blossom", :to=>"Daisy", :what=>"Tulip Admiral of Admirals", :qty=>8},
{:from=>"Vincent", :to=>"Max", :what=>"Tulip Bloemendaal Sunset", :qty=>2},
{:from=>"Anne", :to=>"Martijn", :what=>"Tulip Semper Augustus", :qty=>2},
{:from=>"Ruben", :to=>"Julia", :what=>"Tulip Admiral van Eijck", :qty=>2}]>,
...
Install
Just install the gem:
$ gem install blockchain-lite
License
The blockchain.lite scripts are dedicated to the public domain.
Use it as you please with no restrictions whatsoever.