Ethereum library for the Ruby language
The goal of ethereum.rb is to make interacting with ethereum blockchain from ruby as fast and easy as possible (but not easier!).
Project is currently maintained by @kurotaky.
Before installing gem make sure you meet all prerequisites, especially that you have: * compatible ethereum node installed * compatible solidity compiler installed * wallet with some ethereum on it
Before you run a program check that the node is running and accounts you want to spend from are unlocked.
To install gem simply add this line to your application's Gemfile:
gem 'ethereum.rb'
And then execute:
$ bundle
Or install it yourself as:
$ gem install ethereum.rb
You can create contract from solidity source and deploy it to the blockchain, with following code:
contract = Ethereum::Contract.create(file: "greeter.sol") address = contract.deploy_and_wait("Hello from ethereum.rb!")
Deployment may take up to couple of minutes. Once deployed you can start interacting with contract, e.g. calling it's methods:
contract.call.greet # => "Hello from ethereum.rb!"
You can see example contract greeter here.
If contract method name uses camel case you must convert it to snake case when use call:
call.your_method.
If you want to complie multiple contracts at once, you can create new instances using newly declared ruby clasess:
Ethereum::Contract.create(file: "mycontracts.sol", client: client) contract = MyContract1.new contract = contract.deploy_and_wait contract2 = MyContract2.new contract2 = contract.deploy_and_wait
All names used to name contract in solidity source will translate to name of classes in ruby (camelized).
Note: If class of given name exist it will be undefined first to avoid name collision.
The other way to obtain contract instance is get one that already exist in the blockchain. To do so you need a contract name, contract address and ABI definition.
contract = Ethereum::Contract.create(name: "MyContract", address: "0x01a4d1A62F01ED966646acBfA8BB0b59960D06dd ", abi: abi)
Note that you need to specify contract name, that will be used to define new class in ruby, as it is not a part of ABI definition.
Alternatively you can obtain abi definition and name from contract source file:
contract = Ethereum::Contract.create(file: "MyContract.sol", address: "0x01a4d1A62F01ED966646acBfA8BB0b59960D06dd ")
If you want to create new contract, that is not yet deployed from ABI definition you will need also to supply binary code:
contract = Ethereum::Contract.create(name: "MyContract", abi: abi, code: "...")
If you use Truffle to build and deploy contracts, you can pick up the Truffle artifacts to initialize a contract. For example, if you have a MyContract in the Truffle directory at
/my/truffle/project:
contract = Ethereum::Contract.create(name: "MyContract", truffle: { paths: [ '/my/truffle/project' ] }, client: client, address: '0x01a4d1A62F01ED966646acBfA8BB0b59960D06dd')
The contract factory will attempt to load the deployed address from the Truffle artifacts if the client's network is present:
contract = Ethereum::Contract.create(name: "MyContract", truffle: { paths: [ '/my/truffle/project' ] }, client: client)
Functions defined in a contract are exposed using the following conventions:
contract.transact.[function_name](params) contract.transact_and_wait.[function_name](params) contract.call.[function_name](params)
Example Contract in Solidity ``` contract SimpleRegistry { event LogRegister(bytes32 key, string value); mapping (bytes32 => string) public registry;
function register(bytes32 key, string value) { registry[key] = value; LogRegister(key, value); }
function get(bytes32 key) public constant returns(string) { return registry[key]; }
} ```
For contract above here is how to access it's methods:
contract.transact_and_wait.register("performer", "Beastie Boys")
Will send transaction to the blockchain and wait for it to be mined.
contract.transact.register("performer", "Black Eyed Peas")
Will send transaction to the blockchain return instantly.
contract.call.get("performer") # => "Black Eyed Peas"
Will call method of the contract and return result. Note that no transaction need to be send to the network as method is read-only. On the other hand
registermethod will change contract state, so you need to use
transactor
transact_and_waitto call it.
Using the example smart contract described above, one can listen for
LogRegisterevents by using filters.
You can get a list of events from a certain block number to the latest:
require 'ostruct'event_abi = contract.abi.find {|a| a['name'] == 'LogRegister'} event_inputs = event_abi['inputs'].map {|i| OpenStruct.new(i)} decoder = Ethereum::Decoder.new
filter_id = contract.new_filter.log_register( { from_block: '0x0', to_block: 'latest', address: '0x....', topics: [] } )
events = contract.get_filter_logs.log_register(filter_id)
events.each do |event| transaction_id = event[:transactionHash] transaction = ethereum.eth_get_transaction_receipt(transaction_id) args = decoder.decode_arguments(event_inputs, entry['data']) puts "#{transaction.inspect} with args: #{args}" end
By default methods interacting with contracts will use default Json RPC Client that will handle connection to ethereum node. Default client communicate via IPC. If you want to create custom client or use multiple clients you can create them yourself.
To create IPC client instance of simply create Ethereum::IpcClient:
client = Ethereum::IpcClient.new
You can also customize it with path to ipc file path and logging flag:
client = Ethereum::IpcClient.new("~/.parity/mycustom.ipc", false)
If no ipc file path given, IpcClient looks for ipc file in default locations for parity and geth. The second argument is optional. If it is true then logging is on.
By default logging is on and logs are saved in "/tmp/ethereumrubyhttp.log".
To create Http client use following:
client = Ethereum::HttpClient.new('http://localhost:8545')
You can supply client when creating a contract:
contract = Ethereum::Contract.create(client: client, ...)
You can also obtain default client:
client = Ethereum::Singleton.instance
Ethereum.rb allows you to interact directly with Ethereum node using json rpc api calls. Api calls translates directly to client methods. E.g. to call
eth_gasPricemethod:
client.eth_gas_price # => {"jsonrpc"=>"2.0", "result"=>"0x4a817c800", "id"=>1}
Note: methods are transated to underscore notation.
Full list of json rpc methods is available here
Ethereum.rb supports signing transactions with key using ruby-eth gem.
To create a new key simply do the following:
key = Eth::Key.new
Then you can use the key to deploy contracts and send transactions, i.e.:
contract = Ethereum::Contract.create(file: "...") contract.key = key contract.deploy_and_wait("Allo Allo!") contract.transact_and_wait.set("greeting", "Aloha!")
You can also transfer ether transfer using custom keys:
client.transfer(key, "0x342bcf27DCB234FAb8190e53E2d949d7b2C37411", amount) client.transfer_and_wait(key, "0x949d7b2C37411eFB763fcDCB234FAb8190e53E2d", amount)
You can change gas price or gas limit in the client:
client.gas_limit = 2_000_000_ client.gas_price = 24_000_000_000
or per contract:
ruby contract.gas_limit = 2_000_000_ contract.gas_price = 24_000_000_000
Often in the application you want to link to blockchain explorer. This can be problematic if you want links to work with different networks (ropsten, mainnet, kovan) depending on environment you're working on. Following helpers will generate link according to network connected:
link_to_tx("See the transaction", "0x3a4e53b01274b0ca9087750d96d8ba7f5b6b27bf93ac65f3174f48174469846d") link_to_address("See the wallet", "0xE08cdFD4a1b2Ef5c0FC193877EC6A2Bb8f8Eb373")
They use etherscan.io as a blockexplorer.
Note: Helpers work in rails environment only, works with rails 5.0+.
There are couple of rake tasks to help in wallet maintenance, i.e.:
rake ethereum:contract:deploy[path] # Compile and deploy contract rake ethereum:contract:compile[path] # Compile a contract rake ethereum:transaction:byhash[id] # Get info about transaction rake ethereum:transaction:send[address,amount] # Send [amount of] ether to an account
Logs from communication between ruby app and node are available under following path:
/tmp/ethereum_ruby_http.log
Run
bin/consolefor an interactive prompt that will allow you to experiment.
Make sure
rake ethereum:test:setuppasses before running tests.
Then, run
rake specto run the tests.
Test that do send transactions to blockchain are marked with
blockchaintag. Good practice is to run first fast tests that use no ether and only if they pass, run slow tests that do spend ether. To do that use the following line:
$ bundle exec rspec --tag ~blockchain && bundle exec rspec --tag blockchain
You need ethereum node up and running for tests to pass and it needs to be working on testnet (Ropsten).
This library has been forked from ethereum-ruby by DigixGlobal Pte Ltd (https://dgx.io).
The gem is available as open source under the terms of the MIT License.