Class: Steem::TransactionBuilder

Inherits:
Object
  • Object
show all
Includes:
ChainConfig, Retriable, Utils
Defined in:
lib/steem/transaction_builder.rb

Overview

TransactionBuilder can be used to create a transaction that the NetworkBroadcastApi can broadcast to the rest of the platform. The main feature of this class is the ability to cryptographically sign the transaction so that it conforms to the consensus rules that are required by the blockchain.

wif = '5JrvPrQeBBvCRdjv29iDvkwn3EQYZ9jqfAHzrCyUvfbEbRkrYFC'
builder = Steem::TransactionBuilder.new(wif: wif)
builder.put(vote: {
  voter: 'alice',
  author: 'bob',
  permlink: 'my-burgers',
  weight: 10000
})

trx = builder.transaction
network_broadcast_api = Steem::CondenserApi.new
network_broadcast_api.broadcast_transaction_synchronous(trx: trx)

The wif value may also be an array, when signing with multiple signatures (multisig).

Constant Summary

Constants included from ChainConfig

ChainConfig::EXPIRE_IN_SECS, ChainConfig::EXPIRE_IN_SECS_PROPOSAL, ChainConfig::NETWORKS_STEEM_ADDRESS_PREFIX, ChainConfig::NETWORKS_STEEM_CHAIN_ID, ChainConfig::NETWORKS_STEEM_CORE_ASSET, ChainConfig::NETWORKS_STEEM_DEBT_ASSET, ChainConfig::NETWORKS_STEEM_DEFAULT_NODE, ChainConfig::NETWORKS_STEEM_VEST_ASSET, ChainConfig::NETWORKS_TEST_ADDRESS_PREFIX, ChainConfig::NETWORKS_TEST_CHAIN_ID, ChainConfig::NETWORKS_TEST_CORE_ASSET, ChainConfig::NETWORKS_TEST_DEBT_ASSET, ChainConfig::NETWORKS_TEST_DEFAULT_NODE, ChainConfig::NETWORKS_TEST_VEST_ASSET, ChainConfig::NETWORK_CHAIN_IDS

Constants included from Retriable

Retriable::MAX_BACKOFF, Retriable::MAX_RETRY_COUNT, Retriable::MAX_RETRY_ELAPSE, Retriable::RETRYABLE_EXCEPTIONS

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from Utils

#hexlify, #unhexlify

Methods included from Retriable

#can_retry?

Constructor Details

#initialize(options = {}) ⇒ TransactionBuilder

Returns a new instance of TransactionBuilder.



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# File 'lib/steem/transaction_builder.rb', line 36

def initialize(options = {})
  @app_base = !!options[:app_base] # default false
  @database_api = options[:database_api]
  @block_api = options[:block_api]
  
  if app_base?
    @database_api ||= Steem::DatabaseApi.new(options)
    @block_api ||= Steem::BlockApi.new(options)
  else
    @database_api ||= Steem::CondenserApi.new(options)
    @block_api ||= Steem::CondenserApi.new(options)
  end
  
  @wif = [options[:wif]].flatten
  @signed = false
  @testnet = !!options[:testnet]
  
  if !!(trx = options[:trx])
    trx = case trx
    when String then JSON[trx]
    else; trx
    end
    
    trx_options = {
      ref_block_num: trx['ref_block_num'],
      ref_block_prefix: trx['ref_block_prefix'],
      extensions: (trx['extensions']),
      operations: trx['operations'],
      signatures: (trx['signatures']),
    }
    
    trx_options[:expiration] = case trx['expiration']
    when String then Time.parse(trx['expiration'] + 'Z')
    else; trx['expiration']
    end
    
    options = options.merge(trx_options)
  end
  
  @ref_block_num = options[:ref_block_num]
  @ref_block_prefix = options[:ref_block_prefix]
  @operations = options[:operations] || []
  @expiration = options[:expiration]
  @extensions = options[:extensions] || []
  @signatures = options[:signatures] || []
  @chain = options[:chain] || :steem
  @error_pipe = options[:error_pipe] || STDERR
  @chain_id = options[:chain_id]
  @chain_id ||= case @chain
  when :steem then NETWORKS_STEEM_CHAIN_ID
  when :test then NETWORKS_TEST_CHAIN_ID
  else; raise UnsupportedChainError, "Unsupported chain: #{@chain}"
  end
  
  if testnet? && @chain_id == NETWORKS_STEEM_CHAIN_ID
    raise UnsupportedChainError, "Unsupported testnet chain id: #{@chain_id}"
  end
end

Instance Attribute Details

#app_base ⇒ Object Also known as: app_base?

Returns the value of attribute app_base.



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# File 'lib/steem/transaction_builder.rb', line 29

def app_base
  @app_base
end

#block_api ⇒ Object

Returns the value of attribute block_api.



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# File 'lib/steem/transaction_builder.rb', line 29

def block_api
  @block_api
end

#database_api ⇒ Object

Returns the value of attribute database_api.



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# File 'lib/steem/transaction_builder.rb', line 29

def database_api
  @database_api
end

#expiration ⇒ Object

Returns the value of attribute expiration.



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# File 'lib/steem/transaction_builder.rb', line 29

def expiration
  @expiration
end

#operations ⇒ Object

Returns the value of attribute operations.



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# File 'lib/steem/transaction_builder.rb', line 29

def operations
  @operations
end

#signed ⇒ Object (readonly)

Returns the value of attribute signed.



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# File 'lib/steem/transaction_builder.rb', line 31

def signed
  @signed
end

#testnet ⇒ Object (readonly) Also known as: testnet?

Returns the value of attribute testnet.



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# File 'lib/steem/transaction_builder.rb', line 31

def testnet
  @testnet
end

#wif=(value) ⇒ Object (writeonly)

Sets the attribute wif

Parameters:

  • value —

    the value to set the attribute wif to.



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# File 'lib/steem/transaction_builder.rb', line 30

def wif=(value)
  @wif = value
end

Instance Method Details

#expired? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/steem/transaction_builder.rb', line 120

def expired?
  @expiration.nil? || @expiration < Time.now
end

#inspect ⇒ Object 



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# File 'lib/steem/transaction_builder.rb', line 95

def inspect
  properties = %w(
    ref_block_num ref_block_prefix expiration operations extensions
    signatures
  ).map do |prop|
    if !!(v = instance_variable_get("@#{prop}"))
      "@#{prop}=#{v}" 
    end
  end.compact.join(', ')
  
  "#<#{self.class.name} [#{properties}]>"
end

#potential_signatures ⇒ Array

Returns All public keys that could possibly sign for a given transaction.

Returns:

  • (Array) —

    All public keys that could possibly sign for a given transaction.



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# File 'lib/steem/transaction_builder.rb', line 299

def potential_signatures
  potential_signatures_args = if app_base?
    {trx: transaction}
  else
    transaction
  end
  
  @database_api.get_potential_signatures(potential_signatures_args) do |result|
    if app_base?
      result[:keys]
    else
      result
    end
  end
end

#prepare ⇒ TransactionBuilder

If the transaction can be prepared, this method will do so and set the expiration. Once the expiration is set, it will not re-prepare. If you call #put, the expiration is set Nil so that it can be re-prepared.

Usually, this method is called automatically by #put and/or #transaction.

Returns:



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# File 'lib/steem/transaction_builder.rb', line 131

def prepare
  if expired?
    catch :prepare_header do; begin
      @database_api.get_dynamic_global_properties do |properties|
        block_number = properties.last_irreversible_block_num
        block_header_args = if app_base?
          {block_num: block_number}
        else
          block_number
        end
      
        @block_api.get_block_header(block_header_args) do |result|
          header = if app_base?
            result.header
          else
            result
          end
          
          @ref_block_num = (block_number - 1) & 0xFFFF
          @ref_block_prefix = unhexlify(header.previous[8..-1]).unpack('V*')[0]
          @expiration ||= (Time.parse(properties.time + 'Z') + EXPIRE_IN_SECS).utc
        end
      end
    rescue => e
      if can_retry? e
        @error_pipe.puts "#{e} ... retrying."
        throw :prepare_header
      else
        raise e
      end
    end; end
  end
  
  self
end

#put(type, op = nil) ⇒ TransactionBuilder

A quick and flexible way to append a new operation to the transaction. This method uses ducktyping to figure out how to form the operation.

There are three main ways you can call this method. These assume that op_type is a Symbol (or String) representing the type of operation and op is the operation Hash.

put(op_type, op)

… or …

put(op_type => op)

… or …

put([op_type, op])

You can also chain multiple operations:

builder = Steem::TransactionBuilder.new
builder.put(vote: vote1).put(vote: vote2)

Returns:



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# File 'lib/steem/transaction_builder.rb', line 196

def put(type, op = nil)
  @expiration = nil
  @operations << normalize_operation(type, op)
  prepare
  self
end

#required_signatures ⇒ Array

This API will take a partially signed transaction and a set of public keys that the owner has the ability to sign for and return the minimal subset of public keys that should add signatures to the transaction.

Returns:

  • (Array) —

    The minimal subset of public keys that should add signatures to the transaction.



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# File 'lib/steem/transaction_builder.rb', line 320

def required_signatures
  required_signatures_args = if app_base?
    {trx: transaction}
  else
    [transaction, []]
  end
  
  @database_api.get_required_signatures(*required_signatures_args) do |result|
    if app_base?
      result[:keys]
    else
      result
    end
  end
end

#reset ⇒ Object 



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# File 'lib/steem/transaction_builder.rb', line 108

def reset
  @ref_block_num = nil
  @ref_block_prefix = nil
  @expiration = nil
  @operations = []
  @extensions = []
  @signatures = []
  @signed = false
  
  self
end

#sign ⇒ Hash | TransactionBuilder

Appends to the signatures array of the transaction, built from a serialized digest.

Returns:



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# File 'lib/steem/transaction_builder.rb', line 230

def sign
  return self if @wif.empty?
  return self if expired?
  
  trx = {
    ref_block_num: @ref_block_num,
    ref_block_prefix: @ref_block_prefix, 
    expiration: @expiration.strftime('%Y-%m-%dT%H:%M:%S'),
    operations: @operations,
    extensions: @extensions,
    signatures: @signatures
  }
  
  unless @signed
    catch :serialize do; begin
      transaction_hex_args = if app_base?
        {trx: trx}
      else
        trx
      end
      
      @database_api.get_transaction_hex(transaction_hex_args) do |result|
        hex = if app_base?
          result.hex
        else
          result
        end
        
        hex = @chain_id + hex[0..-4] # Why do we have to chop the last two bytes?
        digest = unhexlify(hex)
        digest_hex = Digest::SHA256.digest(digest)
        private_keys = @wif.map{ |wif| Bitcoin::Key.from_base58 wif }
        ec = Bitcoin::OpenSSL_EC
        count = 0
        sigs = []
        
        private_keys.each do |private_key|
          sig = nil
          
          loop do
            count += 1
            @error_pipe.puts "#{count} attempts to find canonical signature" if count % 40 == 0
            public_key_hex = private_key.pub
            sig = ec.sign_compact(digest_hex, private_key.priv, public_key_hex, false)
            
            next if public_key_hex != ec.recover_compact(digest_hex, sig)
            break if canonical? sig
          end
          
          @signatures << hexlify(sig)
        end
        
        @signed = true
        trx[:signatures] = @signatures
      end
    rescue => e
      if can_retry? e
        @error_pipe.puts "#{e} ... retrying."
        throw :serialize
      else
        raise e
      end
    end; end
  end
    
  Hashie::Mash.new trx
end

#transaction ⇒ Object

If all of the required values are set, this returns a fully formed transaction that is ready to broadcast.

Returns:

  • {

       :ref_block_num => 18912,
:ref_block_prefix => 575781536,
      :expiration => "2018-04-26T15:26:12",
      :extensions => [],
      :operations => [[:vote, {
           :voter => "alice",
          :author => "bob",
        :permlink => "my-burgers",
          :weight => 10000
        }
    ]],
      :signatures => ["1c45b65740b4b2c17c4bcf6bcc3f8d90ddab827d50532729fc3b8f163f2c465a532b0112ae4bf388ccc97b7c2e0bc570caadda78af48cf3c261037e65eefcd941e"]

    }



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# File 'lib/steem/transaction_builder.rb', line 221

def transaction
  prepare
  sign
end

#valid? ⇒ Boolean

Returns True if the transaction has all of the required signatures.

Returns:

  • (Boolean) —

    True if the transaction has all of the required signatures.



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# File 'lib/steem/transaction_builder.rb', line 337

def valid?
  verify_authority_args = if app_base?
    {trx: transaction}
  else
    transaction
  end
  
  @database_api.verify_authority(verify_authority_args) do |result|
    if app_base?
      result.valid
    else
      result
    end
  end
end