undefined method `map' for "1,2":String - ruby-on-rails

Question

I need to pass an array in a params, possible? Values can be, for example, ["1","2","3","4","5"] and these are strings but needs to eb converted to integers later.
I use a react_component in between a rails form_for. The html is like this:
<input type="hidden" name="people_id" id="people_id" value={this.state.people} />
The people array looks like this:
How can I pass the array in the value of the hidden field? The server error I got was
Im trying to do something like this in a model:
ids = params[:people_id]
ids.map do |b|
Foo.create!(people_id: b.to_i)
end
If I ids.split(",").map I get symbol to int error.
Edit:
––––––––––––––––––––––––––––––––––––––––––––––––––––––––––
Still not sure what the issue is as nothing works. Here is a minimal reproduction of my code:
This answer is my react component and that's how I add to the array. Still in the component, I have the hidden field:
<input type="hidden" name="[people_id][]" id="people_id" value={this.state.people} />
_form.html.erb:
<%= form_for resource, as: resource_name, url: registration_path(resource_name), :html => { :data => {:abide => ''}, :multipart => true } do |f| %>
<!-- react component goes here -->
<%= f.submit "Go", class: "large button" %>
<% end %>
The story is, guest can select few people during registration in one go. Those people will be notified when registration is complete. Think of it as "I am inviting these people to bid on my tender". Those numbers, in the array, are user_ids.
users/registrations_controller.rb
class Users::RegistrationsController < Devise::RegistrationsController
# POST /resource
def create
super do |resource|
ids = params[:people_id].pop # logs now as "people_id"=>["1,2"]
resource.save!(ids.split(",").map |b| Foo.create!(people_id: b.to_i) end)
end
end
end
New error on line resource.save:
no implicit conversion of Symbol into Integer
Edit #2
If I only have, in the create method:
ids.split(",").map do |b|
resource.save!(Foo.create!(people_id: b.to_i))
end
It works! Foo is created two times each with the correct people_id.
Because I am creating more objects: Bar, I do not know how to do that in:
resource.save!(<the loop for Foo> && Bar.create!())
The flow must be:
Device creates the User
Foo is created with the loop
Bar is created
etc
It has to be done that way as an User object is created on the fly.

Answer 1

In Rails you use parameter keys with brackets on the end to pass arrays.
However you should not concatenate the values as a comma seperated list but rather send each value as a seperate param:
GET /foo?people_ids[]=1&people_ids[]=2&people_ids[]=3
That way Rails will unpack the parameters into an array:
Parameters: {"people_ids"=>["1", "2", "3"]}
The same principle applies to POST except that the params are sent as formdata.
If you want a good example of how this works then look at the rails collection_check_boxes helper and the inputs it generates.
<input id="post_author_ids_1" name="post[author_ids][]" type="checkbox" value="1" checked="checked" />
<label for="post_author_ids_1">D. Heinemeier Hansson</label>
<input id="post_author_ids_2" name="post[author_ids][]" type="checkbox" value="2" />
<label for="post_author_ids_2">D. Thomas</label>
<input id="post_author_ids_3" name="post[author_ids][]" type="checkbox" value="3" />
<label for="post_author_ids_3">M. Clark</label>
<input name="post[author_ids][]" type="hidden" value="" />
Updated:
If you intend to implement you own array parameters by splitting a string you should not end the input with brackets:
<input type="hidden" name="[people_id][]" value="1,2,3">
{"people_id"=>["1,2,3"]}
Notice how people_id is treated as an array and the input value is the first element.
While you could do params[:people_id].first.split(",") it makes more sense to use the correct key from the get go:
<input type="hidden" name="people_id" value="1,2,3">
Also you don't really want to wrap the "root" key in brackets. Thats used in rails to nest a param key in a hash eg. user[name].