问题
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.
article has many photo.
The logs are as followings.
\log/development.log
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)
delete all(three) images (no error message was displayed)
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 http://localhost:3000/users/1
Completed 302 Found in 26ms (ActiveRecord: 7.0ms)
photos table
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
# 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
class Photo < ActiveRecord::Base
belongs_to :article
mount_uploader :image, ImageUploader
end
\view\articles\edit.html.erb
<div class="row">
<div class="span8">
<%= render 'shared/article_form' %>
</div>
</div>
\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
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
回答1:
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
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.”.
Fix:
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
来源：https://stackoverflow.com/questions/25819209/rails4-to-check-for-no-image-uploaded-with-carrierwave-is-not-working-when-dele