How do I parsing data from JSON object?

I'm just starting to dabble in consuming a JSON web service, and I am having a little trouble working out the best way to get to the actual data elements.

I am receiving a response which has been converted into a Ruby hash using the JSON.parse method. The hash looks like this:

{"response"=>{"code"=&开发者_Python百科gt;2002, "payload"=>{"topic"=>[{"name"=>"Topic Name", "url"=>"http://www.something.com/topic", "hero_image"=>{"image_id"=>"05rfbwV0Nggp8", "hero_image_id"=>"0d600BZ7MZgLJ", "hero_image_url"=>"http://img.something.com/imageserve/0d600BZ7MZgLJ/60x60.jpg"}, "type"=>"PERSON", "search_score"=>10.0, "topic_id"=>"0eG10W4e3Aapo"}]}, "message"=>"Success"}}

What I would like to know, is what is the easiest way to get to the "topic" data so I can do something like:

topic.name = json_resp.name
topic.img = jsob_resp.hero_image_url
etc

You can use Hashie's Mash . One of the best twitter clients for ruby uses it, and the resulting interface is very clean and easy to use. I've wrapped over Delicious rss api with it in less than 60 lines.

As usuall, the specs show very clearly how to use it.