Form Objects in Rails - ruby-on-rails

Question

The example code below is a contrived example of an attempt at a form object where it is probably overkill to utilize a form object. Nonetheless: it shows the issue I am having:
I have two models: a User and an Email:
# app/models/user.rb
class User < ApplicationRecord
has_many :emails
end
# app/models/user.rb
class Email < ApplicationRecord
belongs_to :user
end
I want to create a form object which creates a user record, and then creates three associated email records.
Here are my form object classes:
# app/forms/user_form.rb
class UserForm
include ActiveModel::Model
attr_accessor :name, :email_forms
validates :name, presence: true
def save
if valid?
persist!
true
else
false
end
end
private
def persist!
puts "The Form is VALID!"
puts "I would proceed to create all the necessary objects by hand"
user = User.create(name: name)
email_forms.each do |email|
Email.create(user: user, email_text: email.email_text)
end
end
end
# app/forms/email_form.rb
class EmailForm
include ActiveModel::Model
attr_accessor :email_text, :user_id
validates :email_text, presence: true
def save
if valid?
persist!
true
else
false
end
end
private
def persist!
puts "The Form is VALID!"
# DON'T THINK I WOULD PERSIST DATA HERE
# INSTEAD DO IT IN THE user_form
end
end
Notice: the validations on the form objects. A user_form is considered to be invalid if it's name attribute is blank, or if the email_text attribute is left blank for any of the email_form objects inside it's email_forms array.
For brevity: I will just be going through the new and create action of utilizing the user_form:
# app/controllers/user_controller.rb
class UsersController < ApplicationController
def new
#user_form = UserForm.new
#user_form.email_forms = [EmailForm.new, EmailForm.new, EmailForm.new]
end
def create
#user_form = UserForm.new(user_form_params)
if #user_form.save
redirect_to users_path, notice: 'User was successfully created.'
else
render :new
end
end
private
def user_form_params
params.require(:user_form).permit(:name, {email_forms: [:_destroy, :id, :email_text, :user_id]})
end
end
Lastly: the form itself:
# app/views/users/new.html.erb
<h1>New User</h1>
<%= render 'form', user_form: #user_form %>
<%= link_to 'Back', users_path %>
# app/views/users/_form.html.erb
<%= form_for(user_form, url: users_path) do |f| %>
<% if user_form.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(user_form.errors.count, "error") %> prohibited this user from being saved:</h2>
<ul>
<% user_form.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :name %>
<%= f.text_field :name %>
</div>
# MESSY, but couldn't think of a better way to do this...
<% unique_index = 0 %>
<% user_form.email_forms.each do |email_form| %>
<div class="field">
<%= label_tag "user_form[email_forms][#{unique_index}][email_text]", "Email Text" %>
<%= text_field_tag "user_form[email_forms][#{unique_index}][email_text]" %>
</div>
<% unique_index += 1 %>
<% end %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
The form does render:
And here is the form's html:
I go to submit the form. Here is the params hash:
Parameters: {"utf8"=>"✓", "authenticity_token"=>”abc123==", "user_form"=>{"name"=>"neil", "email_forms"=>{"0"=>{"email_text"=>"test_email_1"}, "1"=>{"email_text"=>"test_email_2"}, "2"=>{"email_text"=>""}}}, "commit"=>"Create User form"}
What should happen is the form should be re-rendered and nothing persisted because the form_object is invalid: All three associated emails must NOT be blank. However: the form_object thinks it is valid, and it blows up in the persist! method on the UserForm. It highlights the Email.create(user: user, email_text: email.email_text) line and says:
undefined method `email_text' for ["0", {"email_text"=>"test_email_1"}]:Array
Clearly there are a couple things going on: The nested validations appear to not be working, and I am having trouble rebuilding each of the emails from the params hash.
Resources I have already examined:
This Article seemed promising but I was having trouble getting it to work.
I have attempted an implementation with the virtus gem and the reform-rails gem. I have pending questions posted for both of those implementations as well: virtus attempt here and then reform-rails attempt here.
I have attempted plugging in accepts_nested_attributes, but was having trouble figuring out how to utilize that with a form object, as well as a nested form object (like in this code example). Part of the issue was that has_many and accepts_nested_attributes_for do not appear to be included in ActiveModel::Model.
Any guidance on getting this form object to do what is expected would be very much appreciated! Thanks!

Answer 1

Complete Answer
Models:
#app/models/user.rb
class User < ApplicationRecord
has_many :emails
end
#app/models/email.rb
class Email < ApplicationRecord
belongs_to :user
end
Controller:
#app/controllers/users_controller.rb
class UsersController < ApplicationController
def index
#users = User.all
end
def new
#user_form = UserForm.new
#user_form.emails = [EmailForm.new, EmailForm.new, EmailForm.new]
end
def create
#user_form = UserForm.new(user_form_params)
if #user_form.save
redirect_to users_path, notice: 'User was successfully created.'
else
render :new
end
end
private
def user_form_params
params.require(:user_form).permit(:name, {emails_attributes: [:email_text]})
end
end
Form Objects:
#app/forms/user_form.rb
class UserForm
include ActiveModel::Model
attr_accessor :name, :emails
validates :name, presence: true
validate :all_emails_valid
def emails_attributes=(attributes)
#emails ||= []
attributes.each do |_int, email_params|
email = EmailForm.new(email_params)
#emails.push(email)
end
end
def save
if valid?
persist!
true
else
false
end
end
private
def persist!
user = User.new(name: name)
new_emails = emails.map do |email_form|
Email.new(email_text: email_form.email_text)
end
user.emails = new_emails
user.save!
end
def all_emails_valid
emails.each do |email_form|
errors.add(:base, "Email Must Be Present") unless email_form.valid?
end
throw(:abort) if errors.any?
end
end
app/forms/email_form.rb
class EmailForm
include ActiveModel::Model
attr_accessor :email_text, :user_id
validates :email_text, presence: true
end
Views:
app/views/users/new.html.erb
<h1>New User</h1>
<%= render 'form', user_form: #user_form %>
<%= link_to 'Back', users_path %>
#app/views/users/_form.html.erb
<%= form_for(user_form, url: users_path) do |f| %>
<% if user_form.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(user_form.errors.count, "error") %> prohibited this User from being saved:</h2>
<ul>
<% user_form.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :name %>
<%= f.text_field :name %>
</div>
<%= f.fields_for :emails do |email_form| %>
<div class="field">
<%= email_form.label :email_text %>
<%= email_form.text_field :email_text %>
</div>
<% end %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>