Missing Param in Rails 6 Form - ruby-on-rails

Question

This is my first Rails 6 project. Stuck on this. Any advice would be appreciated.
I have a form on index.html.erb
<%= form_with model: #volunteer_submission do |form| %>
<%= form.text_field :email %>
<%= form.text_field :first_name %>
<%= form.text_field :last_name %>
<%= form.submit %>
<% end %>
with a controller
def create
#volunteer_submission = VolunteerSubmission.new(volunteer_submission_params)
#volunteer_submission.save
redirect_to #volunteer_submissions
end
def volunteer_submission_params
params.require(:volunteer_submission).permit(:email, :first_name, :last_name)
end
I get this
Started POST "/volunteer_submissions" for ::1 at 2020-03-29 13:55:38 -0700
Processing by VolunteerSubmissionsController#create as JS
Parameters: {"authenticity_token"=>"OIlkqKqXJeA7XjYPqQHubZFGm64ivCe+9fimFwO8uBrtXJ3iPyiIZbgWtWS4FXFnS+KhZYCT5CgzN76YCTqC+Q==", "email"=>"a", "first_name"=>"a", "last_name"=>"a", "commit"=>"Save "}
Completed 400 Bad Request in 2ms (ActiveRecord: 0.0ms | Allocations: 666)
ActionController::ParameterMissing (param is missing or the value is empty: volunteer_submission):
app/controllers/volunteer_submissions_controller.rb:16:in `volunteer_submission_params'
app/controllers/volunteer_submissions_controller.rb:10:in `create'
If I leave out the volunteer_submission_params..it will attempt it...but I think rolls back because I have the DB set up for it not to accept null values. So...I'm not sure why the params aren't passing.
Started POST "/volunteer_submissions" for ::1 at 2020-03-29 13:40:33 -0700
Processing by VolunteerSubmissionsController#create as JS
Parameters: {"authenticity_token"=>"1cpAIcVZuM/qcJdt1KNg2rYMIX58yDVCO5mRMXmbiUjMHr81cAseqJZN/TDYDFaGXGLPJhs7iIwhvQgr5g/RRg==", "email"=>"a", "first_name"=>"a", "last_name"=>"a", "commit"=>"Save "}
(0.3ms) BEGIN
↳ app/controllers/volunteer_submissions_controller.rb:11:in `create'
VolunteerSubmission Create (7.1ms) INSERT INTO "volunteer_submissions" ("created_at", "updated_at") VALUES ($1, $2) RETURNING "id" [["created_at", "2020-03-29 20:40:33.125665"], ["updated_at", "2020-03-29 20:40:33.125665"]]
↳ app/controllers/volunteer_submissions_controller.rb:11:in `create'
(0.4ms) ROLLBACK
↳ app/controllers/volunteer_submissions_controller.rb:11:in `create'
Completed 500 Internal Server Error in 14ms (ActiveRecord: 7.8ms | Allocations: 3296)
ActiveRecord::NotNullViolation (PG::NotNullViolation: ERROR: null value in column "email" violates not-null constraint
routes
Rails.application.routes.draw do
resources :volunteer_submissions
devise_for :admin_users, ActiveAdmin::Devise.config
ActiveAdmin.routes(self)
get 'volunteers', to: 'volunteer_submissions#index'
root to: 'pages#home'
end

Answer 1

I believe your issue is the fact that you are sending your params without a volunteer_submission key.
Based on this method
def volunteer_submission_params
params.require(:volunteer_submission).permit(:email, :first_name, :last_name)
end
Your controller is expecting { "authenticity_token"=>"OIlkqKqXJeA7XjYPqQHubZFGm64ivCe+9fimFwO8uBrtXJ3iPyiIZbgWtWS4FXFnS+KhZYCT5CgzN76YCTqC+Q==", "volunteer_submission" => { "email"=>"a", "first_name"=>"a", "last_name"=>"a" }}.

Answer 2

the form should look like this <%= form_with(model: item, local: true) do |form| %> also in model: item you should put the name of your model rb file located in app/models
in my case its app/models/item.rb
so my form is <%= form_with(model: item, local: true) do |form| %>

Answer 3

for me I had this issue because I was using an html input inside the rails form and was passing in the name of value without the model name.
<% form_with model: order_item do |f| %>
<input type="number" name="weight_in_oz"></input>
<% end %>
params look like this
{"authenticity_token"=>"...", "weight_in_oz"=>"16", "commit"=>"Add To Cart", "controller"=>"order_items", "action"=>"create"} permitted: false>
I fixed this by adding the model name before the input name and put the attribute in an array which nests the attribute inside of a model hash inside of params.
<% form_with model: order_item do |f| %>
<input type="number" name="order_item[weight_in_oz]"></input>
<% end %>
and this is the params after just what I was expecting
{"authenticity_token"=>"....", "order_items"=>{":weight_in_oz"=>"16"}, "commit"=>"Add To Cart", "controller"=>"order_items", "action"=>"create"} permitted: false>