ReXML & to_json

Rails
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

On Jan 24, 2008 5:38 PM, Stuart G. [email protected]
wrote:

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

–
Rick O.
http://lighthouseapp.com
http://weblog.techno-weenie.net
http://mephistoblog.com

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

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.

5

On Jan 25, 11:52 pm, Stuart Grimshaw [email protected]
wrote:

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.

I’ve been trying this approach:

sourceXml = Document.new(lots of xml)

xml = Document.new(‘’)

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