ReXML & to_json

rubyonrails-talk
1

Does REXML support to_json? I keep getting "object references itself" when I do this (simplified version):

    xml = Document.new("<root><ooh fert='nerdle'>Narf!</ooh></root>")

   @json = xml.to_json

Is it possible to output this xml as json.

The source xml is actually much larger, and I want to execute some xpath on that, and return the results as json.

-S

2

Apparently not, but you can probably use Hash.from_xml, which parses the XML into a hash using REXML and SimpleXML.

hash = Hash.from_xml("...") json = hash.to_json

3

> Is it possible to output this xml as json.

> The source xml is actually much larger, and I want to execute some > xpath on that, and return the results as json.

Apparently not, but you can probably use Hash.from_xml, which parses the XML into a hash using REXML and SimpleXML.

hash = Hash.from_xml("...") json = hash.to_json

Cheers Rick,

That works, trying to do the same with xml.elements(xpath) introduces a new problem though, I feel I'm close to working it out, but it's late, and I'm going to bed.

I'm trying to take a fairly large xml document (from a 3rd party url), run an xpath query on it, then return those results as json to my client side js.

4

I've been trying this approach:

sourceXml = Document.new(lots of xml)

xml = Document.new('<data/>')

xml.entities.each(xpath) { |e|    xml.root.add e }

Which works, but takes a very long time to complete. Is this the most efficient way to do it? I might just create a hash right there, from the attributes I'm interested in, rather than send the whole lot back.

-S

5

I've been trying this approach:

sourceXml = Document.new(lots of xml)

xml = Document.new('<data/>')

xml.entities.each(xpath) { |e|    xml.root.add e

}

Which works, but takes a very long time to complete. Is this the most efficient way to do it? I might just create a hash right there, from the attributes I'm interested in, rather than send the whole lot back.

In the end I ditched rexml and went with the ruby libxml bindings to speed things up. Then built a hash up with the results like this:

    @i = Hash.new

    elem = xml.find(xpath).each do |e|       messageId = e.parent.parent['message_id']       @i[messageId] = Hash.new       @i[messageId]['summary'] = e.find_first('./element')['summary']        .        .     end

The just call to_json on @i

Hopefully this will be usefull to anyone else doing the same kind of thing.