Rails 4: Multiple image upload using paperclip - ruby-on-rails

Question

I'm looking to upload multiple images to my 'locations' model. I've called the images model 'assets'. One location has multiple assets. I'm also using paperclip to handle the uploads and nested_form to allow selecting multiple assets.
Weirdly, the locations hash looks to be passing the variables correctly, but they don't appear to be being picked up by the assets model. Any help would be great!
Location model
class Location < ActiveRecord::Base
has_many :location_post
has_many :posts, :through => :location_post
has_many :assets, dependent: :destroy
attr_accessor :asset, :assets_attributes
accepts_nested_attributes_for :assets, :allow_destroy => true
end
Asset model
class Asset < ActiveRecord::Base
belongs_to :location
has_attached_file :asset,
:styles => {
:blurred => "600x300^",:large => "600x600>", :medium => "250x250^" , :thumb => "100x100^"},
#:source_file_options => {:all => '-rotate "-90>"'},
:convert_options => {
:all => '-auto-orient', :blurred => "-blur 0x6 +repage -resize 600x300^"
},
:storage => :s3,
:s3_credentials => "#{Rails.root}/config/s3.yml",
:bucket => "[bucketname]",
:path => "/:style/:id/:filename"
validates_attachment_content_type :asset, :content_type => ["image/jpg", "image/jpeg", "image/png", "image/gif"]
end
Locations Controller
class LocationsController < ApplicationController
...
def new
#location = Location.new
#location.assets.build
#georesult = Geocoder.search(params[:query])
end
def create
#location = Location.find_or_create_by(name: location_params[:name])
respond_to do |format|
if #location.save
format.html { redirect_to #location, notice: ' <borat voice> Great success! </borat voice>' }
format.json { render :show, status: :created, location: #location }
else
format.html { render :new }
format.json { render json: #location.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /locations/1
# PATCH/PUT /locations/1.json
def update
respond_to do |format|
if #location.update(location_params)
format.html { redirect_to #location, notice: 'Location was successfully updated.' }
format.json { render :show, status: :ok, location: #location }
else
format.html { render :edit }
format.json { render json: #location.errors, status: :unprocessable_entity }
end
end
end
...
private
# Use callbacks to share common setup or constraints between actions.
def location_params
params[:location].permit(:name, :notes, :longitude, :country, :latitude, :query, assets_attributes: [ :asset, :asset_content_type, :asset_file_name, :tempfile, :asset_file_size, :asset_updated_at, :_destroy])
end
end
Form View
<%= nested_form_for(#location, :html=> {:multipart => true}) do |f| %>
...
<%= f.fields_for :assets do |a| %>
<%= a.file_field :asset %>
<%= a.link_to_remove "Remove this image" %>
<% end %>
<%= f.link_to_add "Add an image", :assets %>
...
<%= f.submit "Submit", :class => "btn btn-success submit_location" %>
<% end %>
Log output
Processing by LocationsController#update as HTML
Parameters: {"utf8"=>"✓", "authenticity_token"=>"n4spoLjq4B3sZSJjqsGFRVjkseOwGgvquAHATBRG1Nk=", "location"=>{"name"=>"York", "notes"=>"", "lat
itude"=>"53.96230079999999", "longitude"=>"-1.0818844", "country"=>"", "assets_attributes"=>{"0"=>{"asset"=>#<ActionDispatch::Http::UploadedFile
:0x007ff739b7bb68 #tempfile=#<Tempfile:/var/folders/sc/gps8hkgj7yg31j81gpnfg9h00000gn/T/RackMultipart20140706-43312-kdpghs>, #original_filename=
"78509.max1024.jpg", #content_type="image/jpeg", #headers="Content-Disposition: form-data; name=\"location[assets_attributes][0][asset]\"; filen
ame=\"78509.max1024.jpg\"\r\nContent-Type: image/jpeg\r\n">, "_destroy"=>"false"}}}, "commit"=>"Submit", "id"=>"240"}
User Load (0.6ms) SELECT "users".* FROM "users" WHERE "users"."id" = 1 ORDER BY "users"."id" ASC LIMIT 1
Location Load (0.4ms) SELECT "locations".* FROM "locations" WHERE "locations"."id" = $1 LIMIT 1 [["id", 240]]
(0.2ms) BEGIN
(0.3ms) COMMIT
Redirected to http://localhost:3000/locations/240
Completed 302 Found in 9ms (ActiveRecord: 1.6ms)

Answer 1

I see couple of problems in your code:
First thing, you need to remove the following line from Location model:
attr_accessor :asset, :assets_attributes
as its making asset and asset_attributes as virtual attributes which is why they are not saved in database. Also, you don't need asset attribute in Location model as its been taken care by Asset model.
Then, update the location_params as suggested by #Pavan:
def location_params
## Use `require` method
params.require(:location).permit(:name, :notes, :longitude, :country, :latitude, :query, assets_attributes: [ :asset, :asset_content_type, :asset_file_name, :tempfile, :asset_file_size, :asset_updated_at, :_destroy])
end
Next, update the create action as below to ensure Locations are unique by name:
def create
#location = Location.find_by(name: location_params[:name])
unless #location
#location = Location.new(location_params)
end
respond_to do |format|
if #location.save
format.html { redirect_to #location, notice: ' <borat voice> Great success! </borat voice>' }
format.json { render :show, status: :created, location: #location }
else
format.html { render :new }
format.json { render json: #location.errors, status: :unprocessable_entity }
end
end
end

Answer 2

try using <%= a.file_field :asset, :multiple=>"true",:name=>"location[assets][asset][]"%> for handling multiple uploads.
Hope it helps