Strong Parameters : Hash param is missing or the value is empty - ruby-on-rails

Question

I have a form where I have a table with checkboxes in order to select rows and save IDs in my DB.
But it throws me an error:
Param is missing or the value is empty: leadallocation"
I tried different ways but still nor working. So at the moment I just wand to save the hash in my db. Thanks.
# Never trust parameters from the scary internet, only allow the white list through.
def leadallocation_params
params.require(:leadallocation).permit(:campaign_id, :company_id, :user_id)
end
Request Parameters:
{"utf8"=>"✓",
"authenticity_token"=>"GruGL758jT4FO+t/BTRGLrD2uCGOj/qUCrB5VswquzR9N7JZ/rouLmGZnTE7A+XTARiLwkOy1n3/zMqhzuenmg==",
"company_ids"=>["38",
"40"],
"commit"=>"Create Leadallocation"}
The controller
class LeadallocationsController < ApplicationController
before_action :set_leadallocation, only: [:show, :edit, :update, :destroy]
# GET /leadallocations
# GET /leadallocations.json
def complete
end
def index
#leadallocations = Leadallocation.all
end
# GET /leadallocations/1
# GET /leadallocations/1.json
def show
end
# GET /leadallocations/new
def new
#leadallocation = Leadallocation.new
#comps = Company.all
end
# GET /leadallocations/1/edit
def edit
end
# POST /leadallocations
# POST /leadallocations.json
def create
#leadallocation = Leadallocation.new(leadallocation_params)
#leadallocation.company_id = params[:company_ids]
respond_to do |format|
if #leadallocation.save
format.html { redirect_to #leadallocation, notice: 'Leadallocation was successfully created.' }
format.json { render :show, status: :created, location: #leadallocation }
else
format.html { render :new }
format.json { render json: #leadallocation.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /leadallocations/1
# PATCH/PUT /leadallocations/1.json
def update
respond_to do |format|
if #leadallocation.update(leadallocation_params)
format.html { redirect_to #leadallocation, notice: 'Leadallocation was successfully updated.' }
format.json { render :show, status: :ok, location: #leadallocation }
else
format.html { render :edit }
format.json { render json: #leadallocation.errors, status: :unprocessable_entity }
end
end
end
# DELETE /leadallocations/1
# DELETE /leadallocations/1.json
def destroy
#leadallocation.destroy
respond_to do |format|
format.html { redirect_to leadallocations_url, notice: 'Leadallocation was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_leadallocation
#leadallocation = Leadallocation.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def leadallocation_params
params.require(:leadallocation).permit(:campaign_id, :company_id, :user_id)
end
end
The models
class Leadallocation < ActiveRecord::Base
belongs_to :campaign
belongs_to :company
belongs_to :user
end
class User < ActiveRecord::Base
# Include default devise modules. Others available are:
# :confirmable, :lockable, :timeoutable and :omniauthable
has_many :activities
belongs_to :campaign
has_many :leadallocations
devise :database_authenticatable, :registerable,
:recoverable, :rememberable, :trackable, :validatable
end
class Company < ActiveRecord::Base
belongs_to :campaign
has_many :subsidiaries
has_many :leadallocations
end
class Campaign < ActiveRecord::Base
belongs_to :client
has_many :leads
has_many :activities
has_many :contacts
has_many :users
has_many :leadallocations
end
Routes.rb
resources :leadallocations
The view
<h1>New Leadallocation</h1>
<p id="notice"><%= notice %></p>
<h1>Listing Companies</h1>
<%= simple_form_for(#leadallocation) do |f| %>
<table class="table table-bordered">
<thead>
<tr>
<th></th>
<th>Name</th>
<th>Country</th>
<th colspan="3"></th>
</tr>
</thead>
<tbody>
<% #comps.each do |company| %>
<tr>
<td><%= check_box_tag "company_ids[]", company.id %></td>
<td><%= company.name %></td>
<td><%= company.country %></td>
</tr>
<% end %>
</tbody>
</table>
<br>
<div class="form-actions">
<%= f.button :submit %>
</div>
<% end %>
<%= link_to 'Back', leadallocations_path %>

Answer 1

The way you are using Strong Params requires that your parameters adhere to a specific form.
In this case, you params need to be nested under the key leadallocation
The problem is in your form, instead of check_box_tag, you will want to do f.check_box and use this documentation to see the available options.
This will nest your attributes under the leadallocation, if it doesn't then something might be wrong with your setup of models and forms.
Basically all this is to say you want to change your params from this:
{"utf8"=>"✓",
"authenticity_token"=>"GruGL758jT4FO+t/BTRGLrD2uCGOj/qUCrB5VswquzR9N7JZ/rouLmGZnTE7A+XTARiLwkOy1n3/zMqhzuenmg==",
"company_ids"=>["38",
"40"],
"commit"=>"Create Leadallocation"}
to this:
{"utf8"=>"✓",
"authenticity_token"=>"GruGL758jT4FO+t/BTRGLrD2uCGOj/qUCrB5VswquzR9N7JZ/rouLmGZnTE7A+XTARiLwkOy1n3/zMqhzuenmg==",
"leadallocation" => {
"company_ids"=>["38","40"]
}
"commit"=>"Create Leadallocation"}

Answer 2

The problem is here:
"company_ids"=>["38", "40"]
It should be:
"leadallocation" => {
"company_ids" => ["38", "40"]
}
This is the standard construct for a Rails object to be passed to your db. This is why strong_params is structured the way it is...
params.require(:top_level_param).permit(:child_params)
--
You can get around this by simply using .permit:
#app/controllers/leadallocations_controller.rb
class LeadAllocationsController < ApplicationController
private
def leadallocation_params
params.permit(:company_ids)
end
end
This is not a permanent fix but a HACK!!!
Fix:
#app/views/lead_allocations/new.html.erb
<%= simple_form_for #leadallocations do |f| %>
<%= f.collection_check_boxes :company_ids, Company.all, :id, :name %>
<%= f.submit %>
<% end %>
References here:
Simple Form collection_check_boxes
Rails collection_check_boxes
This should send the data you require back to your controller. Notice the f.___ -- this tells Rails to build a form using the FormBuilder you've invoked around #leadallocations.
Simply, this means that your data will be encapsulated in the {"leadallocations" => ...} params, whereas if you just use check_box_tag, it will assume the data is independent.
Also, never use HTML to stylize your page. The use of <br> and <table> should only be for formatting. CSS is the only way to stylize your application. Your use of <table> seems to be okay; I just wanted to highlight because most people don't get the idea of HTML vs CSS.
Furthermore, there is another problem - with your associations:
class Leadallocation < ActiveRecord::Base
belongs_to :company
end
You cannot assign multiple company ID's to a belongs_to relationship:
I've seen instances where [foreign_key]_ids can be passed, but it's not recommended; indeed, an antipattern.
What you'll be looking for is has_and_belongs_to_many:
#app/models/leadallocation.rb
class LeadAllocation < ActiveRecord::Base
has_and_belongs_to_many :company
end
#app/models/company.rb
class Company < ActiveRecord::Base
has_and_belongs_to_many :leadallocations
end
#join table - companies_leadallocations
This will definitely permit you associate multiple leadallocations per company and vice versa.