update README

Author: Atif Nazir

README.md

@@ -10,14 +10,15 @@ Add this line to your application's Gemfile:
 
 And then execute:
 
-    $ bundle
+    $ bundle install
 
 Or install it yourself as:
 
-    $ gem install block_io -v=1.2.1
+    $ gem install block_io -v=2.0.0
 
 ## Changelog
 
+*07/02/20*: BREAKING CHANGES. Version 2.0.0. Remove support for Ruby < 2.3.0. Behavior and interfaces have changed. By upgrading you'll need to revise your code and tests.  
 *05/10/19*: Prevent inadvertent passing of PINs (user error).  
 *06/25/18*: Remove support for Ruby < 1.9.3 (OpenSSL::Cipher::Cipher). Remove connection_pool dependency.  
 *01/21/15*: Added ability to sweep coins from one address to another.  
@@ -31,14 +32,19 @@ Or install it yourself as:
 It's super easy to get started. In your Ruby shell ($ irb), for example, do this:
 
     require 'block_io'
-    BlockIo.set_options :api_key => 'API KEY', :pin => 'SECRET PIN', :version => 2
-     
+    blockio = BlockIo::Client.new(:api_key => "API KEY", :pin => "SECRET PIN")
+
+If you do not have your PIN, or just wish to use your private key backup directly, do this:
+
+    blockio = BlockIo::Client.new(:api_key => "API KEY", :keys => [BlockIo::Key.from_wif("PRIVATE KEY BACKUP")])
+
 And you're good to go:
 
-    BlockIo.get_new_address
-    BlockIo.get_my_addresses
+    blockio.get_new_address
+    blockio.get_my_addresses
 
-For more information, see https://block.io/api/simple/ruby
+For other initialization options/parameters, see `lib/block_io/client.rb`.  
+For more information, see https://block.io/api/simple/ruby.
 
 ## Contributing
 

block_io.gemspec

@@ -1,4 +1,3 @@
-# coding: utf-8
 lib = File.expand_path('../lib', __FILE__)
 $LOAD_PATH.unshift(lib) unless $LOAD_PATH.include?(lib)
 require 'block_io/version'

lib/block_io/client.rb

@@ -156,6 +156,8 @@ def finalize_signature(args = {}, method_name = "sign_and_finalize_withdrawal")
 
     def api_call(args)
 
+      raise Exception.new("No connections left to perform API call. Please re-initialize BlockIo::Client with :pool_size greater than #{@conn.size}.") unless @conn.available > 0
+      
       response = @conn.with {|http| http.post("/api/v#{@version}/#{args[:method_name]}", :json => args[:params].merge({:api_key => @api_key}))}
 
       begin

lib/block_io/key.rb

@@ -27,7 +27,7 @@ def public_key
     def sign(data)
       # sign the given hexadecimal string
 
-      counter = nil
+      counter = 0
       signature = nil
 
       loop do
@@ -50,7 +50,6 @@ def sign(data)
 
         break if !@use_low_r or Helper.low_r?(signature)
 
-        counter ||= 0
         counter += 1
 
       end
@@ -106,7 +105,7 @@ def self.deterministicGenerateK(data, privkey, extra_entropy = nil, group = ECDS
       k = [0] * 32      
       v = [1] * 32
 
-      e = (extra_entropy.nil? ? [] : [extra_entropy.to_s(16).rjust(64,"0").scan(/../).reverse.join].pack("H*").bytes.to_a)
+      e = (extra_entropy.to_i <= 0 ? [] : [extra_entropy.to_s(16).rjust(64,"0").scan(/../).reverse.join].pack("H*").bytes.to_a)
 
       # step D
       k_data = [v, [0], x, hash, e]