Bitcoin-ruby <img src=“https://api.travis-ci.org/lian/bitcoin-ruby.png?branch=master” />¶ ↑

This is a ruby library for interacting with the bitcoin protocol/network.

Some of the main features are:

Bitcoin::Util provides the basic bitcoin utility functions for base58, ECC, etc.
Bitcoin::Protocol can parse/create (almost?) all protocol messages
Bitcoin::Network::Node connects to peers, fetches the blockchain and keeps it up to date (see NODE for usage)
Bitcoin::Validation validates block and transaction rules
Bitcoin::Storage stores the blockchain and can be queried for transaction data
Bitcoin::Script implementation, create/run scripts and verify signatures
Bitcoin::Key provides a high-level API for creating and handling keys/addresses
Bitcoin::Builder provides a high-level API for creating transactions (and blocks)
Bitcoin::Wallet is a draft implementation of a simple wallet
Bitcoin::Namecoin implements all the namecoin-specific differences (see NAMECOIN)

Compatible with…¶ ↑

ruby 1.9.3
ruby 2.0.0

Installation¶ ↑

We assume you already have a ruby 1.9 or 2.0 compatible interpreter and rubygems environment.

git clone https://github.com/lian/bitcoin-ruby.git; cd bitcoin-ruby
ruby -Ilib bin/bitcoin_node

if you want to have it available system-wide, just build the gem and install it:

gem build bitcoin-ruby.gemspec && gem install bitcoin-ruby-0.0.2.gem

now you can just call bitcoin_node from anywhere.

Note that some aspects of the library (such as networking, storage, etc.) need additional dependencies which are not specified in the gemspec. The core requirements are intentionally kept to a minimum, so nobody has to install unneeded dependencies.

eventmachine to run a node / connect to peers
sequel, sqlite3/pg/mysql to use a storage backend
em-dns or nslookup to get peer addrs from DNS seeds
gir_ffi for the gui
bacon to run the specs

If you would like to install using Bundler, put it in your Gemfile and run bundle install

gem 'bitcoin-ruby', git: 'https://github.com/lian/bitcoin-ruby', branch: 'master', require: 'bitcoin'

Client¶ ↑

There is a node which connects to the network and downloads the blockchain into a database. see NODE, Bitcoin::Network::Node.

It also opens an extra socket where local clients can query statistics, monitor blockchain data, and relay their own transactions to the network. see NODE, Bitcoin::Network::CommandHandler, Bitcoin::Network::CommandClient.

There is a WALLET implementation to manage a set of keys, list balances and create transactions. see WALLET, Bitcoin::Wallet.

Library Usage¶ ↑

There are different aspects to the library which can be used separately or in combination. Here are some ideas of what you could do. There are also some demo scripts in examples/, see EXAMPLES.

Keys/Addresses¶ ↑

Generate a Bitcoin::Key

key = Bitcoin::generate_key
key #=> [<privkey>, <pubkey>]

Get the address from a public key

address = Bitcoin::pubkey_to_address(key[1])
address #=> <bitcoin address>

Check if an address is valid

Bitcoin::valid_address?(address) #=> true

Blocks / Transactions parsing¶ ↑

Parse a Bitcoin::Protocol::Block

raw_block = File.open('spec/bitcoin/fixtures/rawblock-0.bin', 'rb') {|f| f.read}
blk = Bitcoin::Protocol::Block.new(raw_block)
blk.hash #=> 00000000839a8e6886ab5951d76f411475428afc90947ee320161bbf18eb6048
blk.tx.count #=> 1
blk.to_hash #=> ...
Bitcoin::Protocol::Block.from_json( blk.to_json )

Parse a Bitcoin::Protocol::Tx

raw_tx = File.open('spec/bitcoin/fixtures/rawtx-01.bin', 'rb') {|f| f.read}
tx = Bitcoin::Protocol::Tx.new(raw_tx)
tx.hash #=> 6e9dd16625b62cfcd4bf02edb89ca1f5a8c30c4b1601507090fb28e59f2d02b4
tx.in.size #=> 1
tx.out.size #=> 2
tx.to_hash #=> ...
Bitcoin::Protocol::Tx.from_json( tx.to_json )

Bitcoin::Script.new(tx.out[0].pk_script).to_string
#=> "OP_DUP OP_HASH160 b2e21c1db922e3bdc529de7b38b4c401399e9afd OP_EQUALVERIFY OP_CHECKSIG"

Transaction verification / Scripts¶ ↑

Get the matching transactions (in this example tx1 is the spending transaction)

rawtx1 = File.open("spec/bitcoin/fixtures/rawtx-f4184fc596403b9d638783cf57adfe4c75c605f6356fbc91338530e9831e9e16.bin", 'rb') {|f| f.read}
rawtx2 = File.open("spec/bitcoin/fixtures/rawtx-0437cd7f8525ceed2324359c2d0ba26006d92d856a9c20fa0241106ee5a597c9.bin", 'rb') {|f| f.read}
tx1 = Bitcoin::Protocol::Tx.new(rawtx1)
tx2 = Bitcoin::Protocol::Tx.new(rawtx2)

Then simply ask the transaction to verify an input

tx1.verify_input_signature(0, tx2) #=> true

Scripts¶ ↑

If you want to control the Bitcoin::Script yourself, you can do so

txin = tx1.in.first
txout = tx2.out[txin.prev_out_index]
script = Bitcoin::Script.new(txin.script_sig + txout.pk_script)

result = script.run do |pubkey, sig, hash_type|
  hash = tx1.signature_hash_for_input(0, nil, txout.pk_script)
  Bitcoin.verify_signature(hash, sig, pubkey.unpack("H*")[0])
end
result #=> true

Create Transactions¶ ↑

You need to know the previous output you want to spend (tx hash and output index), as well as the private key for the address required to sign for it.

# use testnet so you don't acidentially your whole money!
Bitcoin.network = :testnet3

# make the DSL methods available in your scope
include Bitcoin::Builder

# the previous transaction that has an output to your address
prev_hash = "6c44b284c20fa22bd69c57a9dbff91fb71deddc8c54fb2f5aa41fc78c96c1ad1"

# the number of the output you want to use
prev_out_index = 0

# fetch the tx from whereever you like and parse it
prev_tx = Bitcoin::P::Tx.from_json(open("http://test.webbtc.com/tx/#{prev_hash}.json"))

# the key needed to sign an input that spends the previous output
key = Bitcoin::Key.from_base58("92ZRu28m2GHSKaaF2W7RswJ2iJYpTzVhBaN6ZLs7TENCs4b7ML8")

# create a new transaction (and sign the inputs)
new_tx = build_tx do |t|

  # add the input you picked out earlier
  t.input do |i|
    i.prev_out prev_tx
    i.prev_out_index prev_out_index
    i.signature_key key
  end

  # add an output that sends some bitcoins to another address
  t.output do |o|
    o.value 50000000 # 0.5 BTC in satoshis
    o.script {|s| s.recipient "mugwYJ1sKyr8EDDgXtoh8sdDQuNWKYNf88" }
  end

  # add another output spending the remaining amount back to yourself
  # if you want to pay a tx fee, reduce the value of this output accordingly
  # if you want to keep your financial history private, use a different address
  t.output do |o|
    o.value 49000000 # 0.49 BTC, leave 0.01 BTC as fee
    o.script {|s| s.recipient key.addr }
  end

end

# examine your transaction. you can relay it through http://webbtc.com/relay_tx
# that will also give you a hint on the error if something goes wrong
puts new_tx.to_json

Node / Network connections¶ ↑

The Bitcoin::Network::Node can connect to peers and download the blockchain into a Bitcoin::Storage backend. For now it works completely self-contained:

node = Bitcoin::Network::Node.new(options) # options = {:network => :bitcoin, ...}
node.run

In the future you will be able to register callbacks to the node and control many aspects of its operation yourself. Also see NODE.

If you want to implement your own node, see lib/bitcoin/connection.rb or lib/bitcoin/network/node.rb for examples.

Storage / Database backends¶ ↑

There is support for different storage backends. Each backend can be used with sqlite, postgres or mysql. All backends implement the interface defined in Bitcoin::Storage::Backends::StoreBase and return Bitcoin::Storage::Models.

store = Bitcoin::Storage.sequel(:db => "sqlite://bitcoin.db") # in-memory db
store.get_head #=> block
txouts = store.get_txouts_for_address("15yN7NPEpu82sHhB6TzCW5z5aXoamiKeGy")
txouts.first.value #=> 5000000000
txouts.first.type #=> :pubkey
txouts.first.get_address #=> "15yN7NPEpu82sHhB6TzCW5z5aXoamiKeGy"

See also STORAGE, Bitcoin::Storage::Backends::UtxoStore, Bitcoin::Storage::Backends::SequelStore and Bitcoin::Storage::Backends::DummyStore for details.

Documentation¶ ↑

Always trying to improve, any help appreciated! If anything is unclear to you, let us know!

Documentation is generated using RDoc

rake rdoc

The specs are also a good place to see how something works.

Specs¶ ↑

The specs can be run with

rake bacon

or, if you want to run a single spec

ruby spec/bitcoin/bitcoin_spec.rb

To test the postgres/mysql storage backend, create a database and set it as an environment variable:

echo "create database bitcoin_test" | psql
TEST_DB_POSTGRES="postgres:/bitcoin_test" rake bacon

If you make changes to the code or add functionality, please also add specs.

Development¶ ↑

Any help or feedback is greatly appreciated! From getting knee-deep into elliptic-curve acrobatics, to cleaning up high-level naming conventions, there is something for everyone to do. Even if you are completely lost, just pointing out what is unclear helps a lot!

If you are curious or like to participate in development, drop by #bitcoin-ruby on irc.freenode.net!

scottlingran/bitcoin-ruby