How to get json structure in Rails? - ruby-on-rails

Question

my application should sent structure via json,
that functions works fine:
function send_json()
{
var formData = form2object('myForm');
var json_data = JSON.stringify(formData, null, '\t');
$.post("", json_data);
}
It create json_data and send it via post.
But I don't understand how to catch this data on another side, can you help me ?
I should take this structure and make some actions with it.
when i send data i got json:
{ "type": "test", "ttl": "1", "amount": "1", "rules": { "rule1": "1", "value1": "4444", "stackcount1": "1", "rule2": "2", "value2": "333", "stackcount2": "2" }}
In the contoller i wrote this:
class AdminController < ApplicationController
def index
#json_string = params[:amount]
if !#json_sting.nil?
#json_string = JSON.parse(params[:amount])
end
end
end
in the view(haml) i wrote:
=#json_string
It doesn't work !
But wireshark shows:
POST /admin/ HTTP/1.1
Host: localhost:3000
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20100101 Firefox/14.0.1
Accept: */*
Accept-Language: ru-ru,ru;q=0.8,en-us;q=0.5,en;q=0.3
Accept-Encoding: gzip, deflate
DNT: 1
Connection: keep-alive
Content-Type: application/x-www-form-urlencoded; charset=UTF-8
X-Requested-With: XMLHttpRequest
Referer: http://localhost:3000/admin/
Content-Length: 192
Cookie: _GiftSenderTool_session=BAh7BzoQX2NzcmZfdG9rZW4iMTVyNVJCMTBvcGpKSk5OcFN4bW15YVlpRlF1TUNtb1gwZkY0bTRuRHlsNnM9Ig9zZXNzaW9uX2lkIiU4ZjFjNTNjNTY0MTQ1MGExNmFiODcxZGEyYzU5ZTkxMg%3D%3D--f21bf3b96edc3bc551c8de68acc6da17685d58b4
Pragma: no-cache
Cache-Control: no-cache
{
."type": "test",
."ttl": "1",
."amount": "1",
."rules": {
.."rule1": "1",
.."value1": "4444",
.."stackcount1": "1"
.},
."authenticity_token": "n3B6D/Km9zOgOzlosK/OLHyTCDLk3MyCTlTBinfQcnY="
}
It means that i can't get data.

Answer 1

you have to catch your JSON object in some rails controller action. If your JSON string looks like this:
{ "user": { "id": 1, "name": "Tom" } }
then do it like this:
require "json"
...
def some_action
user = JSON.parse(params[:user])
puts "User id is #{user[:id]}"
...
end