ruby-on-rails - Rails 中的表单对象

Question

下面的示例代码是一个尝试使用表单对象的人为示例，其中使用表单对象可能有点矫枉过正。尽管如此:它显示了我遇到的问题:

我有两个模型:User 和 Email:

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

---

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

我想创建一个表单对象，它创建一个用户记录，然后创建三个关联的电子邮件记录。

这是我的表单对象类:

# 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

注意:表单对象的验证。如果 name 属性为空，或者 email_text 属性为任何 留空，则 user_form 被视为无效email_form 对象在它的 email_forms 数组中。

为简洁起见:我将只介绍利用 user_form 的 new 和 create 操作:

# 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

最后:表单本身:

# 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 %>

表单确实呈现:

这是表单的 html:

我去提交表格。这是参数哈希:

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"}

应该发生的是表单应该被重新呈现并且没有任何东西被保留，因为 form_object 是无效的:所有三个关联的电子邮件都不能为空。然而:form_object 认为它是有效的，它在 UserForm 的 persist! 方法中爆炸了。它突出显示 Email.create(user: user, email_text: email.email_text) 行并说:

undefined method `email_text' for ["0", {"email_text"=>"test_email_1"}]:Array

很明显，有几件事正在发生:嵌套验证似乎不起作用，而且我无法从 params 哈希重建每封电子邮件。

我已经检查过的资源:

• This Article看起来很有希望，但我很难让它发挥作用。
• 我已尝试使用 virtus gem 和 reform-rails gem 进行实现。我也为这两种实现发布了悬而未决的问题:virtus attempt here然后 reform-rails attempt here .
• 我曾尝试插入 accepts_nested_attributes，但在弄清楚如何将其与表单对象以及嵌套表单对象(如本代码示例)一起使用时遇到了麻烦。部分问题是 has_many 和 accepts_nested_attributes_for 似乎没有包含在 ActiveModel::Model 中。

任何有关让此表单对象执行预期操作的指导将不胜感激!谢谢!

Answer 1

完整答案

模型:

#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

表单对象:

#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

观看次数:

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 %>