Rails-style Ruby method for turning a URL query string into a deeply-nested hash

hashify_query_string.rb

require 'uri'

q1 = 'username=charlie&email=charlie@gmail'
q2 = 'user[username]=charlie&user[email]=charlie@gmail.com&user[password]=password'
q3 = 'user[address][street]=market&user[address][zipcode]=94103&user[email]=charlie@gmail.com'


puts URI.decode_www_form(q1).to_s
puts URI.decode_www_form(q2).to_s
puts URI.decode_www_form(q3).to_s

# goal is deeply-nested hash, like so: { 'user' => { 'username'=> 'charlie', 'email' => 'charlie@gmail.com', 'address' => { 'zipcode' => 94103 } }


def encode_www_params(query_string)
  array_of_pairs = URI.decode_www_form(query_string)
  
  result = {}
  array_of_pairs.each do |pair|
    keys = parse_key(pair[0])
    value = pair[1]
    puts [keys, value].to_s
    
    current_hash = result
    keys.each_with_index do |key, idx|
      if idx == keys.length - 1
        current_hash[key] = value
      else
        current_hash[key] ||= {}
        current_hash = current_hash[key]
      end
      puts result.to_s
    end
  end
  result
end


def parse_key(key)
  key.split(/\[|\]\[|\]/)
end


puts encode_www_params(q1)
puts encode_www_params(q2)
puts encode_www_params(q3)