= Bitcoin-ruby

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-0.0.1.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

== 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 there 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 multiple database backends, but currently the only stable one is
the Bitcoin::Storage::Backends::SequelStore backend. 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 Bitcoin::Storage::Backends::StoreBase, Bitcoin::Storage::Backends::SequelStore
and Bitcoin::Storage::Models 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

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!