Using JSON with jRails

I am currently trying to use AJAX in my application via jRails. I am trying to return a JSON object from my controller, and then parse it in my Javascript. I am using json2.js to do the parsing.

Here is the code I currently have:

function getSomething()
{
    $.ajax({
        type: "GET",
        url: "map/testjson",
        success: function(data) {
            var myData = JSON.parse(data[0]);
            window.alert(myData.login);
        }
    });
}

and in the controller:

class Map::MapController < ApplicationController
  def index
  end

  def testjson
    @message = User.find(:all)
    ActiveRecord::Base.include_root_in_json = false
    respond_to do |w|
      w.json { render :json => @message.to_json }
    end

  end
end

The window.alert simply says 'undefined' (without tics).

However, if I change the javascript to window.alert(data) (the raw object returned by the controller) I get:

[{"salt":"aSalt","name":"", "created_at":"2010-03-15T02:34:25Z","remember_token_expires_at": null,"crypted_password":"aPassword", "updated_at":"2010-03-15T02:34:25Z","id":1,"remember_token":null, "login":"zgwrig2","email":"zach@zach.com"}]

This looks like an array of size 1, if I'm looking at it correctly, but I have tried just about every combination of JSON.parse on the data object that I can think of, and nothing seems to开发者_如何学Go work.

Any ideas on what I'm doing wrong here?

EDIT This seems to work fine if there is more than one row in the Users table.

---

When there are more than one row, what you are deal is a String of your object in json format, not your json object representation. Really sorry for me english, i want explaind better ...

And if @message is a null object, because there isnt any messange, the render to json dont make anything, and when you are in your JS, you will have a problem because you dont have any response which worker. You must check your @message object. Maybe you can do that:

w.json {render :json => (@message.nil?) ? 0 : @checkpoint }

then, in your callback function you must check if your data response is "0" (like string) or one object.

---

I can see what you have 2 problems in your code.

It is better if you use $.getJSON to do a JSON request.

1. jQuery is yet a parser of JSON... then in your callback function you only must do:

$(data).each(function(i, user){ // what you like do with a user });

2. In your rails response there a error, is not a w.json { render :json => @message.to_json }, is only w.json { render :json => @message }. Whiout ".to_json".

Hope that helps.