JSON (JavaScript Object Notation) is a lightweight data interchange format. Many web applications use it to send and receive data.

In Ruby you can simply work with JSON.

At first you have to require 'json', then you can parse a JSON string via the JSON.parse() command.

require 'json'

j = '{"a": 1, "b": 2}'
puts JSON.parse(j)
>> {"a"=>1, "b"=>2}

What happens here, is that the parser generates a Ruby Hash (opens new window) out of the JSON.

The other way around, generating JSON out of a Ruby hash is as simple as parsing. The method of choice is to_json:

require 'json'

hash = { 'a' => 1, 'b' => 2 }
json = hash.to_json
puts json
>> {"a":1,"b":2}

You can use JSON together with Ruby symbols. With the option symbolize_names for the parser, the keys in the resulting hash will be symbols instead of strings.

json = '{ "a": 1, "b": 2 }'
puts JSON.parse(json, symbolize_names: true)
>> {:a=>1, :b=>2}