Rails形式：一个字段，显示一个变量的值，但将其保存到另一个变量

Question

我有一个包含用户个人资料数据的编辑表单。用户表中的两个变量是email和new_email。我想在编辑表单中的某个字段显示用户的email，但是如果在该字段中输入了新值，我希望它不会保存< / em>到email，而不是new_email。所以我认为我需要new_email的表单字段，但是会显示email的值。我应该如何调整下面的代码才能实现这一目标？

我目前认为：

<%= form_for(@user) do |f| %>
<%= render 'shared/error_messages', object: f.object %>

<%= f.label :email %>
<%= f.email_field :new_email, class: 'form-control' %>     #!!Relevant line.

<%= f.label :other_fields_like_this %>
<%= f.text_field :other_fields_like_this, class: 'form-control' %>

<%= f.submit "Save changes", class: "btn btn-primary" %>
<% end %>

控制器：

def update
  @user = User.friendly.find(params[:id])
  if @user.update_attributes(userupdate_params)
    if params[:user][:new_email] != @user.email   # That is, if: a new email address is entered, i.e. a value other then the existing value for email is entered
      #save value to new_email instead of to email. How to do this?
       send_confirmation_email
       flash[:success] = "Your email address has not yet been updated. Please check your email for a confirmation link."
       redirect_to @user
     end
    flash[:success] = "Profile updated"
    redirect_to @user
  else
    render 'edit'
  end
end

def userupdate_params
    params.require(:user).permit(#:email,  #email I think can be removed here, since it's new_email whose value will change.
                                 :new_email,
                                 :other_fields_like_this,
                                 :password, 
                                 :password_confirmation)
end

仅提供一些背景信息：在此之后，我打算通过确认电子邮件扩展此信息。如果用户点击确认链接，则new_email的值将覆盖email值。因此，我希望它最初保存到new_email，并且稍后在确认之后保存到email。

Answer 1

您可以使用before_update回调并将其分配给new_email字段。

Answer 2

您可以为输入字段提供默认值：

<%= f.email_field :new_email, value: @user.email, class: 'form-control' %>