How to convert partial XML to hash in Ruby

Question

I have a string which has plain text and extra spaces and carriage returns then XML-like tags followed by XML tags:

String = "hi there.

<SET-TOPIC> INITIATE </SET-TOPIC>

<SETPROFILE>
   <KEY>name</KEY>
   <VALUE>Joe</VALUE>
</SETPROFILE>

 <SETPROFILE>
   <KEY>email</KEY>
   <VALUE>Email@hi.com</VALUE>
</SETPROFILE>

<GET-RELATIONS>
  <COLLECTION>goals</COLLECTION>
  <VALUE>walk upstairs</VALUE>
</GET-RELATIONS>
So what do you think?

Is it true?
 "

I want to parse this similar to use Nori or Nokogiri or Ox where they convert XML to a hash.

My goal is to be able to easily pull out the top level tags as keys and then know all the elements, something like:

Keys = ['SETPROFILE', 'SETPROFILE', 'SET-TOPIC', 'GET-OBJECT']

Values[0] = [{name => Joe}, {email => email@hi.com}]
Values[3] = [{collection => goals}, {value => walk up}]

I have seen several functions like that for true XML but all of mine are partial.

I started going down this line of thinking:

parsed = doc.search('*').each_with_object({}) do |n, h| 
  (h[n.name] ||= []) << n.text 
end

score 1 · Accepted Answer · answered Apr 26 '15 at 00:34

I'd probably do something along these lines if I wanted the keys and values variables:

require 'nokogiri'

string = "hi there.

<SET-TOPIC> INITIATE </SET-TOPIC>

<SETPROFILE>
   <KEY>name</KEY>
   <VALUE>Joe</VALUE>
</SETPROFILE>

 <SETPROFILE>
   <KEY>email</KEY>
   <VALUE>Email@hi.com</VALUE>
</SETPROFILE>

<GET-RELATIONS>
  <COLLECTION>goals</COLLECTION>
  <VALUE>walk upstairs</VALUE>
</GET-RELATIONS>
So what do you think?

Is it true?
"

doc = Nokogiri::XML('<root>' + string + '</root>', nil, nil, Nokogiri::XML::ParseOptions::NOBLANKS)

nodes = doc.root.children.reject { |n| n.is_a?(Nokogiri::XML::Text) }.map { |node| 
  [
    node.name, node.children.map { |c|
      [c.name, c.content]
    }.to_h
  ]
}
nodes
# => [["SET-TOPIC", {"text"=>" INITIATE "}],
#     ["SETPROFILE", {"KEY"=>"name", "VALUE"=>"Joe"}],
#     ["SETPROFILE", {"KEY"=>"email", "VALUE"=>"Email@hi.com"}],
#     ["GET-RELATIONS", {"COLLECTION"=>"goals", "VALUE"=>"walk upstairs"}]]

From nodes it's possible to grab the rest of the detail:

keys = nodes.map(&:first)
# => ["SET-TOPIC", "SETPROFILE", "SETPROFILE", "GET-RELATIONS"]

values = nodes.map(&:last)
# => [{"text"=>" INITIATE "},
#     {"KEY"=>"name", "VALUE"=>"Joe"},
#     {"KEY"=>"email", "VALUE"=>"Email@hi.com"},
#     {"COLLECTION"=>"goals", "VALUE"=>"walk upstairs"}]

values[0] # => {"text"=>" INITIATE "}

If you'd rather, it's possible to pre-process the DOM and remove the top-level text:

doc.root.children.select { |n| n.is_a?(Nokogiri::XML::Text) }.map(&:remove)
doc.to_xml
# => "<root><SET-TOPIC> INITIATE </SET-TOPIC><SETPROFILE><KEY>name</KEY><VALUE>Joe</VALUE></SETPROFILE><SETPROFILE><KEY>email</KEY><VALUE>Email@hi.com</VALUE></SETPROFILE><GET-RELATIONS><COLLECTION>goals</COLLECTION><VALUE>walk upstairs</VALUE></GET-RELATIONS></root>\n"

That makes it easier to work with the XML.

The hardest part is standing back and finding the best way to grab the chunks you need. That comes largely from experience. — the Tin Man, Apr 27 '15 at 04:52

score 0 · Answer 2 · edited May 23 '17 at 12:30

0

Wrap the string content in a node and you can parse that with Nokogiri. The text outside the XML segment will be text node in the new node.

str = "hi there. .... Is it true?"
doc = Nokogiri::XML("<wrapper>#{str}</wrapper>")
segments = doc.xpath('/*/SETPROFILE')

Now you can use "Convert a Nokogiri document to a Ruby Hash" to convert the segments into a hash.

However, if the plain text contains some characters that needs to be escaped in the XML spec you'll need to find those and escape them yourself.

edited May 23 '17 at 12:30

Community

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answered Apr 25 '15 at 08:33

Arie Xiao

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Do I have to explicitly call out the path, such as SETPROFILE? I was hoping that any top level nodes could be in an array such as parsed.keys = ['SETPROFILE','SETPROFILE','GET-OBJECT','SET-TOPIC'] and then the values in the node would be hash. Although in that case what happens if there are no beneath? – Satchel Apr 25 '15 at 13:08

How to convert partial XML to hash in Ruby

2 Answers2