How to preserve order in XML Array to Hash conversion?

I am trying to parse XML in Ruby using Nori, which Nokogiri uses internally. XML repeats multiple tags and the library parses duplicate tags as arrays and non-duplicate 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>

      

analyzed as

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

      

How do I preserve the order of the elements in the resulting hash like the result below?

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

      

(This might be a library related question. But the goal is to know if anyone has encountered a similar problem and how to properly disassemble it)

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1 answer


Nori cannot do this on her own. What you can do is customize 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 outputs the result that the original request was requested, which is different from the XML order:

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

      

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