ruby on rails - param is missing or the value is empty: message

Question

I built a contact form on my rails app using Sendgrid. When filling up the contact form, this error message shows up:

ActionController::ParameterMissing in MessagesController#create

param is missing or the value is empty: message

Started POST "/messages" for ::1 at 2020-12-30 16:41:11 +0100
Processing by MessagesController#create as HTML
  Parameters: {"utf8"=>"?", "authenticity_token"=>"uCP2fAxAwk/i8678+LkKyg8LVDpRhrb8CY3sng1z+G7fDMsBzm07IGlG/5Kcqm/GZyzygu0+LKvvUKyVtNuEuA==", "/messages"=>{"name"=>"Coline", "email"=>"test@yopmail.com", "phone_number"=>"0606060606", "message"=>"jhsjhfjqshf"}, "commit"=>"Envoyer"}
Completed 400 Bad Request in 4ms (ActiveRecord: 0.0ms)

Can anyone please help me figure out why?

My message model:

class Message
  include ActiveModel::Model
  attr_accessor :name, :email, :phone_number, :body
  validates :name, :email, :phone_number, :body, presence: true
end

My message controller:

class MessagesController < ApplicationController
  def new
    @message = Message.new
  end
  
  def create
    @message = Message.new message_params
    if @message.valid?
      MessageMailer.contact(@message).deliver_now
      flash[:success] = "Votre message a bien été envoyé !"
      redirect_to root_path
    else
      flash[:danger] = "Votre message n'a pas pu être envoyé."
      redirect_to root_path
    end
  end

  private
  def message_params
    params.require(:message).permit(:name, :email, :phone_number, :body)
  end

end

My message mailer:

class MessageMailer < ApplicationMailer

  def contact(message)
    @body = message.body
    mail(to: 'myemail@yopmail.com', subject: 'Nouveau message !')
  end 
end

My message mailer views (in both html.erb & text.erb):

<%= @body %>

My contact form:

<%= form_for messages_path, url: messages_path do |f| %>
  <div class="row">
    <div class="col-lg-4 col-md-4 col-sm-12">
      <%= f.text_field  :name, required: true, class: "form-control", placeholder: "Votre nom" %><br>
    </div>
    <div class="col-lg-4 col-md-4 col-sm-12">
      <%= f.text_field :email, required: true, class: "form-control", placeholder: "Votre email" %><br>
    </div>
    <div class="col-lg-4 col-md-4 col-sm-12">
      <%= f.text_field :phone_number, required: true, class: "form-control", placeholder: "Votre numéro de téléphone" %><br>
    </div>
  </div>

  <%= f.text_area :message,
                  rows: 8,
                  cols: 40,
                  required: true,
                  class: "form-control",
                  placeholder: "Votre message"%><br>

  <%= f.submit 'Envoyer', class: 'btn btn-secondary' %>
<% end %>

In my config/environment.rb as well as in my config/environments/production.rb & config/environments/development.rb (SENDGRID_LOGIN and SENDGRID_PWD are both in my .env file):

ActionMailer::Base.smtp_settings = {
    :user_name => ENV['SENDGRID_LOGIN'],
    :password => ENV['SENDGRID_PWD'],
    :domain => 'mydomain.fr',
    :address => 'smtp.sendgrid.net',
    :port => 587,
    :authentication => :plain,
    :enable_starttls_auto => true
  }

I've tried removing the 'require(:message)' in the message_params of my controller --> no error message in my browser, but I'm receiving no email and my terminal says I have unpermitted params:

Started POST "/messages" for ::1 at 2020-12-30 16:02:17 +0100
Processing by MessagesController#create as HTML
  Parameters: {"utf8"=>"?", "authenticity_token"=>"x+dJYWSNThRzlmLBj9KrUD1ZEkzX1wa67jvOvwNh4vKgyHQcpqC3e/gjM6/rwc5cVX609GtvnO0I5o60usmeJA==", "/messages"=>{"name"=>"Coline", "email"=>"test@yopmail.com", "phone_number"=>"0606060606", "message"=>"jhwsdiufhsukjhdfkdbvf"}, "commit"=>"Envoyer"}
Unpermitted parameters: :utf8, :authenticity_token, :/messages, :commit
Redirected to http://localhost:3000/
Completed 302 Found in 5ms (ActiveRecord: 0.0ms)

Answer 1

Error comes from params.require(:message) because your incoming params does not contain :message key (it has "/messages").

This originates in your view - you pass messages_path (which is "/messages") in place of field name/model to form_for. Try:

form_for :message, url: messages_path do |f|
   ...