Contact form in Rails - ruby-on-rails

Question

This is a pretty basic question, but I'm having difficulty incorporating it in to my application. I've looked at other similar questions on SO, but they all are using the contact page as a separate page.
I have a front-end of a Rails app that is just a small public facing site using stellar.js for parallax scrolling.
At the last part of the page, I would like to have a "Contact Us" form, but I'm getting a
NoMethodError in Welcome#index undefined method `model_name' for NilClass:Class
Here are the related files:
routes.rb
TestApp::Application.routes.draw do
get "welcome/index"
root :to => 'welcome#index'
match 'contact' => 'contact#new', :as => 'contact', :via => :get
match 'contact' => 'contact#create', :as => 'contact', :via => :post
app/views/welcome/index.html.erb
<%= render "contact" %>
The partial for the contact section of the page app/views/welcome/_contact.html.erb
<%= form_for #message, :url => contact_path do |form| %>
<fieldset class="fields">
<div class="field">
<%= form.label :name %>
<%= form.text_field :name %>
</div>
<div class="field">
<%= form.label :email %>
<%= form.text_field :email %>
</div>
<div class="field">
<%= form.label :subject %>
<%= form.text_field :subject %>
</div>
<div class="field">
<%= form.label :body %>
<%= form.text_area :body %>
</div>
</fieldset>
<fieldset class="actions">
<%= form.submit "Send" %>
</fieldset>
<% end %>
app/controllers/contact_controller.rb
class ContactController < ApplicationController
def new
#message = Message.new
end
def create
#message = Message.new(params[:message])
if #message.valid?
NotificationsMailer.new_message(#message).deliver
redirect_to(root_path, :notice => "Message was successfully sent.")
else
flash.now.alert = "Please fill all fields."
render :new
end
end
end
message.rb
class Message
include ActiveModel::Validations
include ActiveModel::Conversion
extend ActiveModel::Naming
attr_accessor :name, :email, :subject, :body
validates :name, :email, :subject, :body, :presence => true
validates :email, :format => { :with => %r{.+#.+\..+} }, :allow_blank => true
def initialize(attributes = {})
attributes.each do |name, value|
send("#{name}=", value)
end
end
def persisted?
false
end
end
The question is what do I need to do to make this form to function correctly in the welcome#index view?

Answer 1

You need to have #message = Message.new defined in every action that needs #message to be present.
So that means you need this in WelcomeController:
def index
#message = Message.new
end
A shortcut is to just add it to the top of the partial in case it's not set:
<% #message ||= Message.new %>
(But you need to decide if mixing in calls to the model within your views is your style. Some devs don't have a problem with this, and some do.)

Answer 2

You can change following things:
In routes:
Remove:
match 'contact' => 'contact#new', :as => 'contact', :via => :get
match 'contact' => 'contact#create', :as => 'contact', :via => :post
Add:
resources :contact # It will add 7 default REST routes and standard practice model name should be plural if you created your model with singular then keep it singular
In _contact.html.erb partial form path needs to be new_contact_path
<%= form_for Message.new, :url => contact_path do |form| %>
class Message should inherit ActiveRecord::Base
class Message < ActiveRecord::Base
end
In create action else part should be:
if #message.valid?
NotificationsMailer.new_message(#message).deliver
redirect_to(root_path, :notice => "Message was successfully sent.")
else
flash.now.alert = "Please fill all fields."
render :template => "welcome/index"
end