我要为用户选择至少一张图像（最多3张图像），然后在视图中输入 f.text_area：content 共享的_article_form.html.erb。 我在\models\article.rb中添加了自定义验证 check_for_at_least_image 。 仅在 create 操作中有效（显示错误消息），但在 update 操作中无效。 如何在 update 操作中不检查图像并显示错误消息。
What I want to do is for users to select at least one image (up to 3 images) and to enter f.text_area :content in \views\shared\ _article_form.html.erb. I added a custom validation check_for_at_least_image in \models\article.rb. It works (error message is displayed) only in create action, but it doesn't work in update action. How can I check no image and display error message in update action.
文章有很多照片。
日志与
\log / development.log
\log/development.log
新建时无图像（错误消息已按预期显示）
no image when new create (error message was displayed as I expect)
Started POST "/articles" for 127.0.0.1 at 2014-09-13 10:40:49 +0900 Processing by ArticlesController#create as HTML Parameters: {"utf8"=>"笨・, "authenticity_token"=>"xxxx=", "article"=>{"category_id"=>"1379", "photos_attributes"=>{"0"=>{"article_id"=>""}, "1"=>{"article_id"=>""}, "2"=>{"article_id"=>""}}, "content"=>"test"}, "commit"=>"逋ｻ骭ｲ縺吶ｋ"} [1m[35mUser Load (0.0ms)[0m SELECT "users".* FROM "users" WHERE "users"."remember_token" = 'xxxx' LIMIT 1 [1m[36m (0.0ms)[0m [1mbegin transaction[0m [1m[35m (0.0ms)[0m rollback transaction [1m[36mCategory Load (1.0ms)[0m [1mSELECT "categories".* FROM "categories" WHERE "categories"."id" = ? LIMIT 1[0m [["id", 1379]] Rendered shared/_error_messages.html.erb (1.0ms) Rendered shared/_article_form.html.erb (8.0ms) Rendered articles/new.html.erb within layouts/application (10.0ms) Rendered layouts/_header.html.erb (1.0ms) Rendered layouts/_footer.html.erb (0.0ms) Completed 200 OK in 63ms (Views: 51.0ms | ActiveRecord: 1.0ms)删除全部（三张）图像（未显示错误消息）
Started PATCH "/articles/40" for 127.0.0.1 at 2014-09-13 11:10:00 +0900 Processing by ArticlesController#update as HTML Parameters: {"utf8"=>"笨・, "authenticity_token"=>"xxxx=", "article"=>{"category_id"=>"1379", "photos_attributes"=>{"0"=>{"article_id"=>"40", "_destroy"=>"1", "id"=>"132"}, "1"=>{"article_id"=>"40", "_destroy"=>"1", "id"=>"133"}, "2"=>{"article_id"=>"40", "_destroy"=>"1", "id"=>"134"}}, "content"=>"test"}, "commit"=>"譖ｴ譁ｰ縺吶ｋ", "id"=>"40"} [1m[35mUser Load (0.0ms)[0m SELECT "users".* FROM "users" WHERE "users"."remember_token" = 'xxxx' LIMIT 1 [1m[36mArticle Load (0.0ms)[0m [1mSELECT "articles".* FROM "articles" WHERE "articles"."user_id" = ? AND "articles"."id" = 40 ORDER BY created_at DESC LIMIT 1[0m [["user_id", 1]] [1m[35mArticle Load (1.0ms)[0m SELECT "articles".* FROM "articles" WHERE "articles"."id" = ? ORDER BY created_at DESC LIMIT 1 [["id", "40"]] [1m[36m (0.0ms)[0m [1mbegin transaction[0m [1m[35mPhoto Load (1.0ms)[0m SELECT "photos".* FROM "photos" WHERE "photos"."article_id" = ? AND "photos"."id" IN (132, 133, 134) [["article_id", 40]] [1m[36m (0.0ms)[0m [1mSELECT COUNT(*) FROM "photos" WHERE "photos"."article_id" = ?[0m [["article_id", 40]] [1m[35mSQL (1.0ms)[0m DELETE FROM "photos" WHERE "photos"."id" = ? [["id", 132]] [1m[36mSQL (0.0ms)[0m [1mDELETE FROM "photos" WHERE "photos"."id" = ?[0m [["id", 133]] [1m[35mSQL (0.0ms)[0m DELETE FROM "photos" WHERE "photos"."id" = ? [["id", 134]] [1m[36m (4.0ms)[0m [1mcommit transaction[0m Redirected to localhost:3000/users/1 Completed 302 Found in 26ms (ActiveRecord: 7.0ms)照片表
sqlite> .schema photos CREATE TABLE "photos" ("id" INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, "articl_id" integer, "image" varchar(255), "created_at" datetime, "updated_at" datetim);\models\article.rb
\models\article.rb
# encoding: utf-8 class Article < ActiveRecord::Base belongs_to :user belongs_to :category has_many :photos, dependent: :destroy accepts_nested_attributes_for :photos, reject_if: :all_blank, allow_destroy: true default_scope -> { order('created_at DESC') } validates :content, presence: true, length: { maximum: 140 } validates :user_id, presence: true validates :category_id, presence: true validate :check_for_at_least_image def build_images (3 - self.photos.size).times {self.photos.build} end def check_for_at_least_image errors.add(:image, "select...") if self.photos.size <= 0 end end\models\photo.rb
\models\photo.rb
class Photo < ActiveRecord::Base belongs_to :article mount_uploader :image, ImageUploader end\view\articles\edit.html.erb
\view\articles\edit.html.erb
<div class="row"> <div class="span8"> <%= render 'shared/article_form' %> </div> </div>\view\shared\ _article_form.html.erb
\view\shared\ _article_form.html.erb
<%= form_for(@article) do |f| %> <%= render 'shared/error_messages', object: f.object %> <div class="field"> <%= f.hidden_field :category_id %> <%= f.fields_for :photos do |p| %> <%= p.hidden_field :article_id %> <div class="photo"> <% if p.object.image and p.object.image.file %> <%= image_tag p.object.image.thumb.url %> <p>article:<%= @article.id %></p> <p>photo:<%= p.object.id %></p> <%= p.hidden_field :image_cache if p.object.image_cache %> <label><%= p.check_box :_destroy %>delete</label> <% end %> <%= p.file_field :image %> </div> <% end %> <%= f.text_area :content, placeholder: "Enter content..." %> </div> <%= f.submit class: "btn btn-large btn-primary" %> <% end %>\controllers\articles_controller.rb
\controllers\articles_controller.rb
class ArticlesController < ApplicationController before_action :signed_in_user, only: [:create, :destroy] before_action :correct_user, only: [:update, :destroy] . . def new @article = Article.new @category = Category.find(params[:category]) @article.category_id = @category.id 3.times { @article.photos.build } end def create @article = current_user.articles.build(article_params) if @article.save flash[:success] = "article created!" redirect_to current_user #root_url else @article.build_images render 'new' end end . . def edit @article = Article.find(params[:id]) @article.build_images end def update @article = Article.find(params[:id]) if @article.update(article_params) redirect_to current_user else render 'edit' end end def destroy @article.destroy redirect_to root_url end private def article_params params.require(:article).permit(:content, :category_id, photos_attributes: [:id, :article_id, :image, :image_cache, :_destroy]) end . . end推荐答案
只看了你的问题， 认为可能是您的验证正在对子对象进行销毁调用之前运行 ，并进行了一些搜索，发现 此帖子 ，看来我对运行验证是正确的毁灭之前只是要发布与您的问题相关的指针
Just looked at your question and was thinking that may be your validations are running before the destory call on child objects and searched around a bit and found this post, looks like i was right about validations being run before destory. Just going to post pointer related to your question
这里的问题是，在父对象验证之后，accepts_nested_attributes_for调用销毁了子对象。因此，用户可以删除图像。当然，稍后，当用户尝试编辑文章时，他/她会得到一个错误-选择至少一张图像。。
The problem here is that accepts_nested_attributes_for call destroy for child objects AFTER validation of the parent object. So the user is able to delete an image. Of course, later, when the user will try to edit an article, he/she will get an error – "Select at least one image.".
修复：
accepts_nested_attributes_for :photos, reject_if: proc { |attributes| attributes['image'].blank? } , allow_destroy: true #as discussed in your other question you have to use proc to solve your update problem validate :check_for_at_least_image def check_for_at_least_image errors.add(:image, "select...") if photos.reject(&:marked_for_destruction?).size <= 0 end更多推荐
Rails4：在删除图像时,检查是否没有通过载波上传的图像不起作用
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