Rails 5: increment value to existing array and keep old values - ruby-on-rails

Question

I'm trying to increment new values to an array but the old values get deleted. As you can see in the following, I had one image there and now its NULL, but the new image is there.
SQL (1.5ms) UPDATE "attachments" SET "media_files" = $1, "updated_at" = $2 WHERE "attachments"."id" = $3 [["media_files", "{NULL,image4.jpg}"], ["updated_at", "2018-10-25 09:12:05.564281"], ["id", 11]]
I'm using the carrierwave gem and this is the method I have inside the controller in order to keep the existing values and increment the new ones:
def create
files = #attachment.media_files # copy the old images
files += params[:item][:media_files] # add new file to the files
#attachment.assign_attributes(:media_files => files) # assign back
if #attachment.save
flash[:notice] = "Media files where successfully uploaded"
redirect_back fallback_location: root_path
else
flash[:alert] = "Failed to upload media files"
redirect_back fallback_location: root_path
end
end
And the form is:
<%= form_for #item, url: create_image_path(#attachment), method: :post , :html => {:id => "form"} do |f| %>
<%= f.file_field :media_files, multiple: true %>
<%= f.submit 'Add' %>
<% end %>
Models associations:
class Item < ApplicationRecord
has_many :attachments, dependent: :destroy
accepts_nested_attributes_for :attachments, allow_destroy: true
end
class Attachment < ApplicationRecord
belongs_to :item
mount_uploaders :media_files, AttachmentUploader
validates_presence_of :media_files
end
The schema for the two models:
create_table "attachments", force: :cascade do |t|
t.integer "item_id"
t.integer "account_id"
t.string "media_files", default: [], array: true
t.string "content_type"
t.boolean "success"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "items", force: :cascade do |t|
t.string "title"
t.string "description"
t.integer "category_id"
t.integer "account_id"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
The route for the create method:
post "item/:id/uploads/media_files/:id"=> "attachments#create", :as => :create_image
Any idea what I might be missing here?

Answer 1

You can go with your own code the modification need to done is: -
def create
exitsting_files = #attachment.media_files # copy the old images
new_file = params[:item][:media_files] # new file to the files
new_attachment = Aattachment.new(:media_files => new_file, id: #item.id) #New attachment submitted by form
if new_attachment.save
#push back your exitsting_files along with new one
#attachment.media_files.push(exitsting_files)
#attachment.save
flash[:notice] = "Media files where successfully uploaded"
redirect_back fallback_location: root_path
else
flash[:alert] = "Failed to upload media files"
redirect_back fallback_location: root_path
end
end
However this should be done with nested_atrributes_for concept
<%= form_for #item, url: create_image_path(#attachment), method: :post , :html => {:id => "form"} do |f| %>
<%= f.fields_for : attachments do |ff| %>
<%= ff.file_field :media_files, multiple: true %>
<%end%>
<%= f.submit 'Add' %>
<% end %>
And so on... you can get lots of example for nested form