HashStorage

hash_storage.rb

require 'json'

class Hash
  def deep_merge(tree)
    merger = proc { |key,v1,v2| Hash === v1 && Hash === v2 ? v1.merge(v2, &merger) : v2 }
    self.merge(tree, &merger)
  end
end

class HashStorage
  def initialize
    @opts = {}
  end

  def add options
    tree = Hash.new { |h,k| h[k] = Hash.new(&tree.default_proc) }
    tree = options

    @opts = @opts.deep_merge tree
  end

  def to_s
    @opts.to_json
  end

end

st = HashStorage.new

st.add({'dev' => {'db' => {'host' => "localhost:2828"}}})
st.add({'dev' => {'db' => {'user' => "me"}}})
st.add({'dev' => {'db' => {'password' => "secret"}}})
st.add({'test' => {'db' => {'host' => "localhost:2828"}}})
st.add({'test' => {'db' => {'user' => "test_user"}}})
st.add({'test' => {'db' => {'password' => "test_secret"}}})

puts st.to_s
# => {"dev":{"db":{"host":"localhost:2828","user":"me","password":"secret"}},"test":{"db":{"host":"localhost:2828","user":"test_user","password":"test_secret"}}}