How to retain order in XML Array to Hash conversion?

Question

I'm trying to parse XML in Ruby using Nori, which internally uses Nokogiri. The XML has some tags repeated and the library parses repeated tags as Arrays and non-repeated tags as normal elements (Hash)

<nodes>
  <foo>
    <name>a</name>
  </foo>
  <bar>
    <name>b</name>
  </bar>
  <baz>
    <name>c</name>
  </baz>
  <foo>
    <name>d</name>
  </foo>
  <bar>
    <name>e</name>
  </bar>
</nodes>

is parsed as

{nodes: {
  foo: [{name: "a"}, {name: "d"}],
  bar: [{name: "b"}, {name: "e"}],
  baz: {name: "c"}
}}

How do i retain the order of elements in the resulting hash like the output below?

{nodes: [
      {foo: {name: "a"}}, 
      {bar: {name: "b"}},
      {baz: {name: "c"}},
      {foo: {name: "d"}},
      {bar: {name: "e"}},
    ]}

(This may be a library specific question. But the intention is to know if anyone has faced a similar issue and how to parse it correctly)

Answer 1

Nori can't do this on its own. What you can do is tune the Nori output like this:

input = {nodes: {
  foo: [{name: "a"}, {name: "d"}],
  bar: [{name: "b"}, {name: "e"}],
  baz: {name: "c"}
}}

def unfurl(hash)
  out=[]
  hash.each_pair{|k,v|
    case v
    when Array
      v.each{|item|
        out << {k => item}
      }
    else
      out << {k => v}
    end
  }
  return out
end

output = {:nodes => unfurl(input[:nodes])}

puts output.inspect

This prints the output that the original question requested which is different than the XML order:

{nodes: [
  {foo: {name: "a"}}, 
  {foo: {name: "d"}},
  {bar: {name: "b"}},
  {bar: {name: "e"}},
  {baz: {name: "c"}},
]}