Rails form multiple checkboxes for associated model - ruby-on-rails

Question

I'm creating an application where a "submission" can be made using a form which creates client details and allows "referrals" to be created depending on the branch(es) that can provide the required service
class Submission < ActiveRecord::Base
has_many :referrals, :inverse_of => :submission, dependent: :delete_all
accepts_nested_attributes_for :referrals, :allow_destroy => true
end
class Referral < ActiveRecord::Base
belongs_to :submission
end
class Branch < ActiveRecord::Base
has_many :referrals
end
Submissions controller:
def new
#submission = Submission.new
#submission.build_client
#submission.client.build_address
#submission.referrals.build
end
def submission_params
params.require(:submission).permit(:consent, :user_id, client_attributes:
[:client_id, :first_name,
address_attributes:
[:first_line, :second_line,]
],
referrals_attributes:
[:branch_id]
)
end
The Submission form:
<%= form_for(#submission) do |f| %>
<%= f.fields_for :referrals do |referral| %>
<%= render 'referral_fields', f: referral %>
<% end %>
<% end %>
_referral_fields.html.erb:
<% Branch.all.where(referrable: true).each do |branch| %>
<label>
<%= check_box_tag 'branch_ids[]', branch.id %>
<%= branch.name %>
</label>
<% end %>
What I want is to have checkboxes for each referrable branch. When a branch is ticked and the submission is created, a referral will be created for that branch. However, when I submit the form, I get a validation error of "Referrals can't be blank". Any idea why this is not working?
Any help is most appreciated

Answer 1

Use collection_check_boxes.
<% # _referral_fields.html.erb %>
<%= f.collection_check_boxes(:branch_ids, Branch.where(referrable: true), :id, :name) do |b|
b.label { b.check_box } # wraps check box in label
end %>
You would need to whitelist submission[referrals_attributes][branch_ids] - not branch_id.
def submission_params
params.require(:submission)
.permit(
:consent,
:user_id,
client_attributes: [
:client_id,
:first_name,
address_attributes: [
:first_line, :second_line,
]
],
referrals_attributes: [:branch_ids]
)
end
Edited.
However for this to work you need to setup a relation between Referral and Branch. In this case you could use either a has_and_belongs_to_many (HABTM) or has_many though: (HMT) relationship.
See Choosing Between has_many :through and has_and_belongs_to_many.
class Referral < ActiveRecord::Base
belongs_to :submission
has_and_belongs_to_many :branches
end
class Branch < ActiveRecord::Base
has_and_belongs_to_many :referrals
end
You need to create a join table as well:
rails g migration CreateBranchReferralJoinTable branch referral