Rails: How to turn JS object to array params

Question

I have this JS object:

obj = {id: 80, attr_name: "avatar", style: "small", upload_path: null}

I then post this object as params with AJAX to the controller. What I would like to see in the params is something like this:

params[:attachment][:id] = 80
params[:attachment][:attr_name] = "avatar"

and so on and on...

So on the JS side I created an object that holds attachment params:

{attachment:obj}

While I do get params[:attachment] the result it [object Object].

How can I turn my JS object into an array inside params[:attachment]?

Thanks,

• jlstr: How are you sending the Post request? are you perhaps doing it via jQuery's $.post?

Answer 1

One way is, instead of {attachment: obj} to make it like so:

postData = {
 "attachment[id]": obj.id,
 "attachment[attr_name]": obj.attr_name
}

Another method is to use stringify the JS object as JSON, and JSON.parse it on the other side.

However jQuery.ajax, when you pass an object to the "data" parameter, ought to send it along just fine as is. See: Post an object as data using Jquery Ajax

Answer 2

Assuming you're using jQuery (which is Rails default), this would work:

<h1>TEST</h1>
<script type="text/javascript">
 $(function() {
 params = {};
 params.attachment = {};
 params.attachment.id = 80;
 $.post( "/the_action", params, function(data) {
 alert("response"); 
 }, "json");
 });
</script>

You may verify this in the controller like this:

class MainController < ApplicationController
 respond_to :html, :json
 def index
 end
 def the_action
 print params
 puts params[:attachment][:id]
 render nothing: true
 end
end

That should print the data in the format you desire.

• bymannan: Although my logic tells me it should work, it do not. I am not sure why.
• jlstr: This is the standard way to build JS objects. Really weird if it doesn't work.
• imtk: This is not correct because you'll receive {"attachment"=>"{\"id\":\"80\"}", "format"=>:json, "action"=>"the_action", "controller"=>"main_controller"} as the params in the rails server.