Fix nil issue

blockchain.rb

@@ -13,14 +13,17 @@ def block_at index
 
   def << block
     @blocks << block
+
+    puts block
   end
 
   def work!
     loop do
       next_block = Block.next $blockchain.last, "Transaction Data..."
 
-      puts next_block
       @blocks << next_block
+
+      puts next_block
     end
   end
 end

main.rb

@@ -8,17 +8,21 @@
 class Web < Sinatra::Base
   configure do
     set :port, 4000+rand(1000)
-    # set :quiet, true
-    # set :logging, false
+    set :quiet, true
+    set :logging, false
   end
 
   get '/blocks' do
     json $blockchain.last.to_hash
   end
 
   get '/blocks/:index' do
-    index = params['index']
-    json $blockchain.block_at(index.to_i).to_hash
+    index = params['index'].to_i
+    if index > $blockchain.last.index
+      status 404
+      return
+    end
+    json $blockchain.block_at(index).to_hash
   end
 end
 
@@ -32,16 +36,15 @@ class Web < Sinatra::Base
 
 # Download blocks from the seed node
 if ARGV[0]
-  puts "Seed node: #{seed_node}"
+  puts "Seed node: #{ARGV[0]}"
 
   loop do
     index = $blockchain.last.index.to_i + 1
     response = HTTParty.get("#{ARGV[0]}/blocks/#{index.to_s}")
 
     break if response.code != 200
 
-    $blockchain << Block.from_json_str response.body
-    puts block
+    $blockchain << Block.from_json_str(response.body)
   end
 
   puts 'Finished downloading the chain'