Image from polymorphic model does't display - ruby-on-rails

Question

I have a model named Hen:
class Hen < ApplicationRecord
has_many :pictures, as: :imageable
validates :name, :description, presence: true
end
I added the :picture to whitelisted params in the HensController as well
Picture model:
class Picture < ApplicationRecord
belongs_to :imageable, polymorphic: true
has_attached_file :image
end
When creating new Hen, I can check that the instance is created.
In console Hen.last.pictures returns
[["imageable_id", 3], ["imageable_type", "Hen"], ["LIMIT", 11]]
=> #
,so I assume that it is fine there.
... but I do not know how to dispay it in the view section. After some tries I have done that:
<p><%= #hen.pictures do |pic| %></p>
<%= image_tag pic.url %>
<% end %>
It dispays
#<Picture::ActiveRecord_Associations_CollectionProxy:0x00005640044034f0>*
because I left the "=" there (to check if there is any object inside), but the picture is not displayed. I checked some other variants like pic.image_url and nothing works for me. Other images on the page display without problems.
Console returns status 200:
Processing by HensController#show as HTML
Parameters: {"id"=>"3"}
User Load (0.6ms) SELECT "users".* FROM "users" WHERE "users"."id" = $1 ORDER BY "users"."id" ASC LIMIT $2 [["id", 1], ["LIMIT", 1]]
Hen Load (0.5ms) SELECT "hens".* FROM "hens" WHERE "hens"."id" = $1 LIMIT $2 [["id", 3], ["LIMIT", 1]]
↳ app/controllers/hens_controller.rb:16:in `show'
Rendering hens/show.html.erb within layouts/application
Rendered hens/show.html.erb within layouts/application (Duration: 5.9ms | Allocations: 3302)
[Webpacker] Everything's up-to-date. Nothing to do
Completed 200 OK in 125ms (Views: 67.7ms | ActiveRecord: 10.7ms | Allocations: 36995)*

Answer 1

You're not actually looping through pictures. You need to use #hen.picutres.each or for picture in #hen.pictures. Without this, you're just passing a block to #hen.pictures; the block gets ignored and the expression returns #hen.pictures (Picture::ActiveRecord_Associations_CollectionProxy).
The equivalent plain-ruby would be
#hen.pictures { ... this block isn't used but it's not a syntax error ... }
instead of
#hen.pictures.each { |picture| ... this block is used by the `each` method }

Answer 2

Here <%= #hen.pictures do |pic|%> you are printing the picture url. you should not include = when you are looping <%= #hen %> wrong you should use <% #hen %> then you need to loop the pictures using each.
<% #hen.pictures.each do |pic| %>
<%= image_tag pic.url %>
<% end %>
if the picture url in hash try to convert it into string using .to_s
<%= image_tag pic.url.to_s %>

Answer 3

This may not be the direct answer for the problem, but I found that better option is to use ActiveStorage than creating Polymorphic associations between models.
First, install the ActiveStorage:
rails active_storage:install
then add macro has_one_attached or has_many_attached to the models:
class Hen < ApplicationRecord
has_one_attached :image
validates :name, :description, presence: true
end
add to the view form:
<%= f.file_field :image %>
whitelist the :image attribute:
def hens_params
params.require(:hen).permit(:name, :description, :image)
end
Done.
To dispay the image in views:
<%= image_tag hen.image if hen.image.attached? %>
No need to create new model or to nest attributes.