Remove JSONP for parsing in HTTParty

Question

I'm using Google's definition URL which returns a response stream containing JSONP data (see below).

GET http://www.google.com/dictionary/json?callback=a&sl=en&tl=en&q=epitome

The response looks like this:

a({"query": "epitome", ...}, 200, null)

Before parsing the JSON, I have to strip the callback parameters; that means removing everything before the first { and everything after the last }.

I have regular expression to strip the callback parameters but am having problems using it with an HTTParty request.

Regular Expression to strip padding

^\w+\(|[^}]+$

I've tried using the following, but am getting errors.

base_url = "http://www.google.com/dictionary/json?callback=a&sl=en&tl=en&q="
word = "epitome"

request = HTTParty.get("#{base_url}#{word}").gsub(/^\w+\(|[^}]+$/)

HTTParty automatically tries to parse the data ignoring the gsub! method; so I'm not sure how to add the regexp to strip the callback parameters before HTTParty tries to parse the returned data.

Any tips on this?

Answer 1

Use a custom parser. In this example, I use a substring to strip off the padding, but you could use a regex if you prefer:

require 'httparty'

class JsonpParser < HTTParty::Parser
  SupportedFormats = {"text/javascript" => :jsonp}

  def jsonp
    JSON.load(body[2..-11], nil)
  end

end

class Dictionary
  include HTTParty

  parser JsonpParser

  def self.define(word)
    get "http://www.google.com/dictionary/json?callback=a&sl=en&tl=en&q=#{word}"
  end

end

Dictionary.define 'epitome'