Neil Neil -4 years ago 193
Ruby Question

Rails form object with reform-rails with collections not working or validating

I am using the reform-rails gem In order to utilize a form object in my rails project.

I realize a form object is probably overkill for the example code I use below, but it is for demonstration purposes.

In the form I am creating a

user
, and associated to that user record are two
user_emails
.

# models/user.rb
class User < ApplicationRecord
has_many :user_emails
end

# models/user_email.rb
class UserEmail < ApplicationRecord
belongs_to :user
end


Notice that I am not using
accepts_nested_attributes_for :user_emails
within the
User
model. It appears to me that one of the main points of form objects is that it helps you get away from using
accepts_nested_attributes_for
, so that is why I am attempting to do this without it. I got that idea from this video which talks about refactoring fat models. I have the link pointing to the section of the video on form objects, and he expresses how much he dislikes
accepts_nested_attributes_for
.

I then proceed to create my
user_form
:

# app/forms/user_form.rb
class UserForm < Reform::Form
property :name
validates :name, presence: true

collection :user_emails do
property :email_text
validates :email_text, presence: true
end
end


So the
user_form
object wraps a
user
record and then a couple of
user_email
records associated to that
user
record. There are form-level validations on the
user
and on the
user_email
records this form wraps:


  • the
    user#name
    must have a value

  • each
    user_email#email_text
    must have a value



If the form is valid: then it should create one
user
record and then a couple of associated
user_email
records. If the form is not valid: then it should re-render the form with error messages.

I will show what I have in the controller thus far. For brevity: only displaying the
new
action and the
create
action:

# app/controllers/users_controller.rb
class UsersController < ApplicationController

def new
user = User.new
user.user_emails.build
user.user_emails.build
@user_form = UserForm.new(user)
end

def create
@user_form = UserForm.new(User.new(user_params))
if @user_form.valid?
@user_form.save
redirect_to users_path, notice: 'User was successfully created.'
else
render :new
end
end

private
def user_params
params.require(:user).permit(:name, user_emails_attributes: [:_destroy, :id, :email_text])
end
end


Lastly: the form itself:

# app/views/users/_form.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 :user_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 %>


As a test: here is the form with inputted values:

enter image description here

Now I proceed to submit. What should happen is there should be a validation error because a value for that second email must be present. However, when submitted here are the logs:

Parameters: {"utf8"=>"✓", "authenticity_token"=>”123abc==", "user"=>{"name"=>"neil", "user_emails_attributes"=>{"0"=>{"email_text"=>"email_test1"}, "1"=>{"email_text"=>""}}}, "commit"=>"Create User"}

ActiveModel::UnknownAttributeError (unknown attribute 'user_emails_attributes' for User.):


So there is some issue with my form object.

How can I get this form object to work? Is it possible to use
reform_rails
and get this form object to work without using
accepts_nested_attributes
? Ultimately: I just want to get the form objet to work.

Some resource I have already explored in addition to the reform-rails docs:



My first attempt to make a form object was with the virtus gem, but I could not seem to get that one working either. I did post a stackoverflow question for that implementation as well.

Answer Source

Complete Answer:

Models:

# app/models/user.rb
class User < ApplicationRecord
  has_many :user_emails
end

# app/models/user_email.rb
class UserEmail < ApplicationRecord
  belongs_to :user
end

Form Object:

# app/forms/user_form.rb
# if using the latest version of reform (2.2.4): you can now call validates on property 
class UserForm < Reform::Form
  property :name, validates: {presence: true}

  collection :user_emails do
    property :email_text, validates: {presence: true}
  end
end

Controller:

# app/controllers/users_controller.rb
class UsersController < ApplicationController
  before_action :user_form, only: [:new, :create]

  def new 
  end

  # validate method actually comes from reform this will persist your params to the Class objects
  # you added to the UserForm object. 
  # this will also return a boolean true or false based on if your UserForm is valid. 
  # you can pass either params[:user][:user_emails] or params[:user][user_email_attributes]. 
  # Reform is smart enough to pick up on both.
  # I'm not sure you need to use strong parameters but you can. 

  def create    
    if @user_form.validate(user_params)
      @user_form.save
      redirect_to users_path, notice: 'User was successfully created.'
    else
      render :new
    end
  end

  private

  # call this method in a hook so you don't have to repeat
  def user_form
    user = User.new(user_emails: [UserEmail.new, UserEmail.new])
    @user_form ||= UserForm.new(user)
  end 

  # no need to add :id in user_emails_attributes
  def user_params
    params.require(:user).permit(:name, user_emails_attributes: [:_destroy, :email_text])
   end
 end

The Form:

# 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 :user_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 %>
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