How to solve the “Can't mass-assign protected attributes: translations_attributes” error?

问题

I am using Ruby on Rails (3.2.2), globalize3 (0.2.0) and batch_translations (0.1.2) ruby-gems. I would like to solve the following problem generated when using the batch_translations ruby-gem:

ActiveModel::MassAssignmentSecurity::Error in Admin::ArticlesController#update

Can't mass-assign protected attributes: translations_attributes

In my ROOT_RAILS/Gemfile file I have:

...
gem 'globalize3'
gem 'batch_translations'

In my ROOT_RAILS/app/models/admin/article.rb file I have:

class Admin::Article < ActiveRecord::Base
  translates :title

  # This is needed to make the batch_translations to work.
  accepts_nested_attributes_for :translations

  ...
end

In my ROOT_RAILS/app/views/admin/articles/_form.html.erb file I have:

<%= form_for(@admin_article, :url => admin_article_path) do |f| %>
    <%= f.label :title %><br />
    English translation:
    <%= f.text_field :title %>

    Italiano translation:
    <%
      # Note: I am using the '<%= f...' instad of '<% f...' otherwise
      # batch_translations doesn't output the input field in the
      # front-end content.
    %>
    <%= f.globalize_fields_for :it do |g| %>
      <%= g.text_field :title %>
    <% end %>
<% end %>

In my ROOT_RAILS/app/controllers/admin/articles_controller.html.erb file I have:

class Admin::ArticlesController < ApplicationController

  def update
    @admin_article = Article.find(params[:id])

    respond_to do |format|
      if @admin_article.update_attributes(params[:article])
        format.html { redirect_to admin_article_path(@admin_erticle), notice: 'Article was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: "edit" }
        format.json { render json: @admin_article.errors, status: :unprocessable_entity }
      end
    end
  end

  ...
end

When I show the edit form all works, but when I submit that form I get the error mentioned above. How can I solve the above error?

---

UPDATE

I found the solution by using the following code in the ROOT_RAILS/app/models/admin/article.rb file:

class Admin::Article < ActiveRecord::Base
  translates :title

  attr_accessible :translations_attributes
  accepts_nested_attributes_for :translations

  ...
end

... but making the :translations_attributes accessible is it sure?

回答1:

This will be an issue with the newest version of rails since they patched it. You can change it in the config. See http://weblog.rubyonrails.org/2012/3/30/ann-rails-3-2-3-has-been-released/ for details.

I can confirm that your attr_accessible solution is correct.

回答2:

I had the same problem. I think this is a good solution:

In my Gemfile file I have:

gem 'globalize3', '~> 0.2.0'
gem 'batch_translations', '~> 0.1.2'

In my application.rb file I have:

config.i18n.available_locales = [:es, :en]

In my model (category.rb) I have:

class Category < ActiveRecord::Base
  attr_accessible :name, :translations_attributes

  translates :name

  accepts_nested_attributes_for :translations, :reject_if => proc { |attributes| attributes['name'].blank? }

  validates :name, :presence => true
end

Category::Translation.class_eval do
  attr_accessible :name
end

In my helper (application_helper.rb) I have:

module ApplicationHelper

  def find_available_locales
    locales = {}
    I18n.available_locales.each { |locale| locales[locale] = t("locale_selector.#{locale}") }
    locales
  end

  def available_locales
    @available_locales ||= find_available_locales
  end

end

In my translation files I have:

en.yml

en:
  locale_selector:
    es: 'Spanish'
    en: 'English'

es.yml

en:
  locale_selector:
    es: 'Español'
    en: 'Inglés'

In my view file (_form.html.erb) I have:

<%= form_for @category, html: { class: 'form-horizontal' } do |f| %>
  <% available_locales.each_pair do |locale, name_locale| -%>
    <% if locale == I18n.locale -%>
      <div class="control-group">
        <%= f.label :name, class: 'control-label' %>
        <div class="controls">
          <%= f.text_field :name, class: 'text_field' %> <i>(<%= name_locale %>)</i>
        </div>
      </div>
    <% else -%>
      <%= f.globalize_fields_for locale do |g| -%>
        <div class="control-group">
          <%= g.label :name, class: 'control-label' %>
          <div class="controls">
            <%= g.text_field :name, class: 'text_field' %> <i>(<%= name_locale %>)</i>
          </div>
        </div>
      <% end -%>
    <% end -%>
  <% end -%>

  <div class="form-actions">
    <%= f.submit nil, class: 'btn btn-primary' %>
    <%= link_to t('.cancel', default: t("helpers.links.cancel")),
                categories_path, class: 'btn' %>
  </div>
<% end %>

As you can see, the problem is that rails 3.2 needs to know which attributes can be accesibles, but globalize do not specify this. So I define this with attr_accessible in my model (Category), but I need to add this for translations too, for this reason I add a few lines in the same file to set name accessible for each translation in this model (Category::Translation.class_eval).

回答3:

Yes. Rails is probably configured to only allow mass assignment of attributes that were explicitly allowed.

# This is mass assignment
Model.find(params[id]).update_attributes params[:model]

The whitelist approach is enforced for security. params[:model] can contain anything, even attributes that were not available in the form. An attacker can leverage this and send admin: true along with the other values.

Without attr_accessible, the attacker would have been granted admin rights. However, if :admin had not been on the whitelist, update_attributes would not have updated that specific attribute.

The gems are probably mass assigning under the hood. Make sure you allow them to write to their own attributes.

来源：https://stackoverflow.com/questions/10139245/how-to-solve-the-cant-mass-assign-protected-attributes-translations-attribute