如何将带有表示嵌套的键的哈希转换为嵌套哈希

Question

I need to convert the following hash:

{
  "item[0][size]" => "12",
  "item[0][count]" => "1"
}  

to this:

{
  "item": {
    "0": {
      "size": "12",
      "count": "1"
    }
  }
}  

Could you please advice on how to achieve that most gracefully? Maybe I can reuse some ActionPack's utility method that is used for parsing parameter strings?

Answer 1

You can reuse a rack lib method Rack::Utils.parse_nested_query

require "rack"
def p p
  Rack::Utils.parse_nested_query(p)                                               
end
p 'item[0][size]=12' # => {"item"=>{"0"=>{"size"=>"12"}}}

Found here .

Answer 2

After some research I found a way to parse nested query keys using http://apidock.com/rails/Rack/Utils/parse_nested_query :

Rack::Utils.parse_nested_query('item[0][size]')
=> {
  "item" => {
    "0" => {
      "size" => nil
    }
  }
}

So it's now possible to do:

items_string = item_hash.to_a.map { |row| row.join('=') }.join('&')
result = Rack::Utils.parse_nested_query(items_string)

=> {
  "item" => {
    "0" => {
       "size" => "12",
      "count" => "1"
    }
  }
}