set a block number to use in web3 rpc

Author: donpdonp

lib/web3/eth/contract.rb

@@ -92,7 +92,11 @@ def parse_method_args transaction
         def do_call web3_rpc, contract_address, args
           data = '0x' + signature_hash + encode_hex(encode_abi(input_types, args) )
 
-          response = web3_rpc.eth.call [{ to: contract_address, data: data}, 'latest']
+          block = @web3_rpc.block
+          if block.is_a?(Numeric)
+            block = "0x#{block.to_s(16)}"
+          end
+          response = web3_rpc.eth.call [{ to: contract_address, data: data}, block]
 
           string_data = [remove_0x_head(response)].pack('H*')
           return nil if string_data.empty?

lib/web3/eth/rpc.rb

@@ -16,18 +16,20 @@ class Rpc
 
       DEFAULT_HOST = 'localhost'
       DEFAULT_PORT = 8545
+      DEFAULT_BLOCK = 'latest'
 
       attr_reader :eth, :connect_options
+      attr_accessor :block
 
-      def initialize host: DEFAULT_HOST, port: DEFAULT_PORT, connect_options: DEFAULT_CONNECT_OPTIONS
+      def initialize host: DEFAULT_HOST, port: DEFAULT_PORT, connect_options: DEFAULT_CONNECT_OPTIONS, block: DEFAULT_BLOCK
 
         @client_id = Random.rand 10000000
 
         @uri = URI((connect_options[:use_ssl] ? 'https' : 'http')+ "://#{host}:#{port}#{connect_options[:rpc_path]}")
         @connect_options = connect_options
 
         @eth = EthModule.new self
-
+        @block = block
       end
 
       def trace