How to convert a nested hash into XML using Nokogiri

Question

I have many levels of a nested hash like:

 { :foo => \'bar\', :foo1 => { :foo2 => \'bar2\', :foo3 => \'bar3\', :foo4 => { :foo5 => \'bar5\'         


        

Answer 1

The accepted is a clean solution, but the below really does 'use' Nokogiri to construct XML from a Hash with special handling for attributes:

require 'nokogiri'

def generate_xml(data, parent = false, opt = {})
    return if data.to_s.empty?
    return unless data.is_a?(Hash)

    unless parent
        # assume that if the hash has a single key that it should be the root
        root, data = (data.length == 1) ? data.shift : ["root", data]
        builder = Nokogiri::XML::Builder.new(opt) do |xml|
            xml.send(root) {
                generate_xml(data, xml)
            }
        end

        return builder.to_xml
    end

    data.each { |label, value|
        if value.is_a?(Hash)
            attrs = value.fetch('@attributes', {})
            # also passing 'text' as a key makes nokogiri do the same thing
            text = value.fetch('@text', '') 
            parent.send(label, attrs, text) { 
                value.delete('@attributes')
                value.delete('@text')
                generate_xml(value, parent)
            }

        elsif value.is_a?(Array)
            value.each { |el|
                # lets trick the above into firing so we do not need to rewrite the checks
                el = {label => el}
                generate_xml(el, parent) 
            }

        else
            parent.send(label, value)
        end
    }
end

puts generate_xml(
    {'myroot' => 
        {
            'num' => 99, 
            'title' => 'something witty', 
            'nested' => { 'total' => [99, 98], '@attributes' => {'foo' => 'bar', 'hello' => 'world'}}, 
            'anothernest' => {
                '@attributes' => {'foo' => 'bar', 'hello' => 'world'}, 
                'date' => [
                    'today', 
                    {'day' => 23, 'month' => 'Dec', 'year' => {'y' => 1999, 'c' => 21}, '@attributes' => {'foo' => 'blhjkldsaf'}}
                ]
            }
    }})
puts puts
puts generate_xml({
            'num' => 99, 
            'title' => 'something witty', 
            'nested' => { 'total' => [99, 98], '@attributes' => {'foo' => 'bar', 'hello' => 'world'}}, 
            'anothernest' => {
                '@attributes' => {'foo' => 'bar', 'hello' => 'world'}, 
                'date' => [
                    'today', 
                    {'day' => [23,24], 'month' => 'Dec', 'year' => {'y' => 1999, 'c' => 21}, '@attributes' => {'foo' => 'blhjkldsaf'}}
                ]
            }
    })

And the resulting XML output:

  99
  
  
    99
    98
  
  
    today
    
      23
      Dec
      
        1999
        21
      
    
  





  99
  
  
    99
    98
  
  
    today
    
      23
      24
      Dec
      
        1999
        21