Display a nested image with paperclip and rails - ruby-on-rails

Question

I have two models :
Post and Picture
class Post < ActiveRecord::Base
has_many :picture, :dependent => :destroy
accepts_nested_attributes_for :picture, :allow_destroy => true, :reject_if => lambda { |t| t['pictures'].nil? }
end
and
class Picture < ActiveRecord::Base
belongs_to :posts
has_attached_file :image, styles: { medium: "300x300>", thumb: "100x100>" }, default_url: "/images/:style/missing.png"
validates_attachment_content_type :image, content_type: /\Aimage\/.*\Z/
end
Picture has a paperclip attachment : image
I created a nested form but i'm not able to know if my picture is saved correctly since i can't display in the show page.
Here is my form :
<%= form_for #post, html: { multipart: true} do |f| %>
<% if #post.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#post.errors.count, "error") %> prohibited this post from being saved:</h2>
<ul>
<% #post.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :title %><br>
<%= f.text_field :title %>
</div>
<div class="field">
<%= f.label :description %><br>
<%= f.text_area :description %>
</div>
<div class="field">
<%= f.label :brand %><br>
<%= f.text_field :brand %>
</div>
<div class="field">
<%= f.label :model %><br>
<%= f.text_field :model %>
</div>
<div class="field"><%= f.fields_for :picture do |p| %>
<%= p.file_field :image %>
<% end %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
My show page :
<p id="notice"><%= notice %></p>
<%= #post.picture.each do |pic| %>
<%= image_tag pic.image.url(:medium) %>
<% end %>
<p>
<strong>Title:</strong>
<%= #post.title %>
</p>
<p>
<strong>Description:</strong>
<%= #post.description %>
</p>
<p>
<strong>Brand:</strong>
<%= #post.brand %>
</p>
<p>
<strong>Model:</strong>
<%= #post.model %>
</p>
<%= link_to 'Edit', edit_post_path(#post) %> |
<%= link_to 'Back', posts_path %>
The post controller :
class PostsController < ApplicationController
before_action :set_post, only: [:show, :edit, :update, :destroy]
# GET /posts
# GET /posts.json
def index
#posts = Post.all
end
# GET /posts/1
# GET /posts/1.json
def show
end
# GET /posts/new
def new
#post = Post.new
#post.picture.build
end
# GET /posts/1/edit
def edit
end
# POST /posts
# POST /posts.json
def create
#post = Post.new(post_params)
respond_to do |format|
if #post.save
if params[:image]
params[:image].each { |image|
#post.picture.create(image: image)
}
end
format.html { redirect_to #post, notice: 'Post was successfully created.' }
format.json { render :show, status: :created, location: #post }
else
format.html { render :new }
format.json { render json: #post.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /posts/1
# PATCH/PUT /posts/1.json
def update
respond_to do |format|
if #post.update(post_params)
format.html { redirect_to #post, notice: 'Post was successfully updated.' }
format.json { render :show, status: :ok, location: #post }
else
format.html { render :edit }
format.json { render json: #post.errors, status: :unprocessable_entity }
end
end
end
# DELETE /posts/1
# DELETE /posts/1.json
def destroy
#post.destroy
respond_to do |format|
format.html { redirect_to posts_url, notice: 'Post was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_post
#post = Post.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def post_params
params.require(:post).permit(:title, :description, :brand, :model, picture_attributes: [ :id, :post_id, :image, :_destroy])
end
end
When i heat create post, i have no error the post is rendered but instead of having the image displayed i have this : "[]" ?
Terminal output :
Processing by PostsController#show as HTML
Parameters: {"id"=>"8"}
Post Load (0.4ms) SELECT "posts".* FROM "posts" WHERE "posts"."id" = ? LIMIT 1 [["id", 8]]
Picture Load (0.3ms) SELECT "pictures".* FROM "pictures" WHERE "pictures"."post_id" = ? [["post_id", 8]]
Is there something i did wrong ?

Answer 1

The first issue you have is that you've referenced your associations incorrectly:
#app/models/post.rb
class Post < ActiveRecord::Base
has_many :pictures #-> plural
end
#app/models/picture.rb
class Picture < ActiveRecord::Base
belongs_to :post #-> singular
has_attached_file :image
validates :image, content_type: { content_type: /\Aimage\/.*\Z/ }
end
You can see about the association names here:
A pro tip is to use the paperclip_defaults options in your application.rb:
#config/application.rb
...
config.paperclip_defaults: {
styles: { medium: "300x300>", thumb: "100x100>" },
default_url: "/images/:style/missing.png"
}
This will allow you to set the "defaults" for all implementations of Paperclip in your app, which can be overridden as you need in each model. Just makes it less messy I find...
In regards your error, you have all the pieces in place; I think the issue is your association names (see above).
This is what I would have:
#app/controllers/posts_controller.rb
class PostsController < ApplicationController
def new
#post = Post.new
#post.pictures.build #-> plural
end
def create
#post = Post.new post_params
#post.save
end
private
def post_params
params.require(:post).permit(:title, :description, :brand, :model, picture_attributes: [:image, :_destroy])
end
end
You'd then be able to use the following form:
#app/views/posts/new.html.erb
<%= form_for #post, multipart: true do |f| %>
<%= f.fields_for :pictures do |p| %>
<%= p.file_field :image %>
<% end %>
<%= f.submit %>
<% end %>
--
This should submit to your db properly; to display the images, you can use the following:
#app/views/posts/show.html.erb
<% #post.pictures.each do |picture| %>
<%= image_tag picture.image.url %>
<% end %>