Composing JSON with objects

[kuon]

I am using some PostgreSQL methods to generate some bits of json that I'd like to compose with objects.

Right now I can do something like:

require 'oj'

json = %|
  {
    "some": "json",
    "might": "be large"
  }
|

obj = {
  :rubyobject => "A value",
  :importjson => Oj.load(json, :mode => :compat)
}

Oj.dump(obj, :mode => :compat)

I'd like to do the same, but without decoding and re-encoding the JSON document.

[ohler55]

Let me make sure I understand correctly. I might have a quick addition that would give this to you.

You would like to build a JSON document and insert another document in the one you are creating. Did I understand correctly?

If so, take a look at the newly added Oj::StringWriter. It allows you to build a JSON document one element at a time. I could extend that to add an existing JSON document as a value. Simple addition if the StringWriter works for you.

[kuon]

Yes something like this would work:

require 'oj'

writer = Oj::StringWriter.new

writer.push_object
writer.push_value("A value", 'rubyobject')
writer.push_document('{"some":"json fragment"}', 'jsonfragment') # New API
writer.pop

puts writer.to_s

# Should print something like:

{"rubyobject":"A value","jsonfragment":{"some":"json fragment"}} 

[ohler55]

Cool, I'll let you know when it is added. Will most likely call it push_json(). Try to get it in in the next day or two if not tonight.

[kuon]

Yes push_json makes sense. Thanks for your time.

[ohler55]

Try out release 2.5.0.

[kuon]

I tested release 2.5.1 and it works as expected.

I'm going to use it to compose a large json document (about 100MB out of a PG DB) that is currently decoded and re-encoded, I hope for a speed boost. I'll let you know.

[kuon]

For info I got a huge performance gain over decode/reencode. Thanks a lot.

[ohler55]

Great, glad it helped.