url_query_merge.rb

require 'uri'

Puppet::Functions.create_function(:'profile::url_query_merge') do
    dispatch :url_query_merge do
        required_param 'String', :url
        required_repeated_param 'Variant[String, Array, Hash]', :new_params
        return_type 'String'
    end

    def url_query_merge( url, *new_params )
        # Allow clearing values - for example, a param ?key=remove would remove all instances of key "key"
        #
        # Example: url_query_merge(
        #   "https://signage.example.com/tv.php?&id=39",
        #   ["a=b", "c=d&e=f"], # Array of strings
        #   {'y' => 'z'},       # Hash
        #   "?c=remove&c=123",  # Remove and replace items
        #   {'y1' => 'z1', 'y2' => 'z2', 'y3' => 'z3'}, # Multi-item hash
        #   [{'w' => 'x'}, {'t' => 'u'}], # Array of Hashes
        # )
        #
        # "https://signage.example.com/tv.php?id=39&a=b&e=f&y=z&c=123&y1=z1&y2=z2&y3=z3&w=x&t=u"

        uri = URI.parse(url)
        
        all_query_params = URI.decode_www_form(String(uri.query))

        new_params.each do |i|
            if i.respond_to?(:keys) then
                all_query_params.concat i.map {|k,v| [k, v]}
            elsif i.respond_to?(:each)
                i.each do |j|
                    if j.respond_to?(:keys)
                        all_query_params.concat j.map{ |k,v| [k, v]}
                    else
                        all_query_params.concat URI.decode_www_form(j)
                    end
                end
            else
                all_query_params.concat URI.decode_www_form(i)
            end
        end

        all_query_params.reject! { |k, v| k.empty? }

        final_query_params = []
        all_query_params.each do |k, v|
            if k.start_with?('?') && v == "remove" then
                rk = k[1..-1]
                final_query_params.reject! { |ik,iv| ik == rk }
            else
                final_query_params << [k,v]
            end
        end
        uri.query = URI.encode_www_form(final_query_params)

        return(uri.to_s)
    end
end