Rails 3 and carrierwave: can't convert nil into String

Question

I'm trying to implement upload image with carrierwave gem in my rails application, but when I press the submit button of the form I recive the following error: "can't convert nil into String".

Application trace:

app/controllers/uploads_controller.rb:48:in `new'
app/controllers/uploads_controller.rb:48:in `create'

Request:

{"utf8"=>"✓",
"authenticity_token"=>"VsgoOE/BQwwT0aQRRMO22kxdPgC/BS2H/CnHVBi4Cfw=",
"upload"=>{"name"=>"aaa",
"description"=>"aa",
"image"=>[#<ActionDispatch::Http::UploadedFile:0x508a8b0 @original_filename="c1147374806dce0ec967015c041fec3b.jpg",
@content_type="image/jpeg",
@headers="Content-Disposition: form-data; name=\"upload[image][]\"; filename=\"c1147374806dce0ec967015c041fec3b.jpg\"\r\nContent-Type: image/jpeg\r\n",
@tempfile=#<File:C:/Users/user/AppData/Local/Temp/RackMultipart20150621-5356-1gm0atx>>]},
"commit"=>"Upload"}

upload model:

class Upload < ActiveRecord::Base
    validates_presence_of :user_id, :image
    attr_accessible :name, :description, :image
    mount_uploader :image, ImageUploader
end

upload controller:

class UploadsController < ApplicationController
    before_filter :signed_in_user

    def index
    (...)
    end

    def show
    (...)
    end

    def new
        @upload = Upload.new
        respond_to do |format|
            format.html # new.html.erb
            format.json { render json: @upload }
        end
    end

    def edit
        (...)
    end

    def create
        @upload =  Upload.new(params[:upload])
        @upload.user_id = current_user.id
        respond_to do |format|
            if @upload.save

                format.html { redirect_to @upload, notice: 'Image was uploaded.' }
                format.json { render json: @upload, status: :created, location: @upload }

            else
                format.html { render action: "new" }
                format.json { render json: @upload.errors, status: :unprocessable_entity }
            end
        end
    end

    def update
        (...)
    end

    def destroy
        (...)
    end
end

upload form (uploads/_form.html.erb):

<%= form_for @upload, :html => {:id => "upload_form", :multipart => true} do |f| %>
    <div class="field">
        <%= f.text_field :name, placeholder: 'Title' %>
    </div>
    <div class="field">
        <%= f.text_field :description, placeholder: 'Description' %>
    </div>
    <%= f.file_field :image, multiple: true %>
    <div class="actions">
        <%= f.submit "Upload" %>
    </div>
<% end %>

carrierwave uploader:

class ImageUploader < CarrierWave::Uploader::Base
    storage :file

    def store_dir
        "uploads/#{model.class.to_s.underscore}/#{mounted_as}/#{model.id}"
    end
end

upload schema:

create_table "uploads", :force => true do |t|
    t.string   "name"
    t.string   "description"
    t.integer  "user_id"
    t.datetime "created_at",  :null => false
    t.datetime "updated_at",  :null => false
    t.string   "image"
end

Directory where carrierwave save images:

public
    uploads
        upload
            image
                1
                ...

The line 48 refers by application trace is @upload = Upload.new(params[:upload]).

How can I fix this issue? I can't figure why upload is nil. Can someone put me in the right way?

Some details: OS Win7 Pro, Rails v.3.2.21, Carrierwave v.0.10.0, as IDE Rubymine v.7.1.2

EDIT 1: As suggest from @sreena I switched from upload to image and now this is the request message:

Parameters: {"utf8"=>"✓",
"authenticity_token"=>"G1zpdyCbXRJYqAR5m5hscMjQOry85KN7toNhJznOFok=",
"upload"=>{"name"=>"titolo", "description"=>"descrizione",
"image"=>[#<ActionDispatch::Http::UploadedFile:0x534aef0 @original_filename="2.jpg", 
@content_type="image/jpeg", @headers="Content-Disposition: form-data;
name=\"upload[image][]\"; filename=\"2.jpg\"\r\nContent-Type: image/jpeg\r\n",
@tempfile=#<File:C:/Users/user/AppData/Local/Temp/RackMultipart20150624-4180-14oypoq>>]},
"commit"=>"Upload"}

After press the submit button, now I recive another error raises from the form: "Image can't be blank".

Answer 1

Finally I solved the issue. I just change create method in the following way

def create
    @upload =  current_user.uploads.build(params[:upload])
    @upload.image = params[:upload]["image"]
    respond_to do |format|
    if @upload.save

        format.html { redirect_to @upload, notice: 'Image was uploaded.' }
        format.json { render json: @upload, status: :created, location: @upload }

    else
        format.html { render action: "new" }
        format.json { render json: @upload.errors, status: :unprocessable_entity }
    end
end

Answer 2

in your UploadsContoller page add this function def upload_params params.require(:upload).permit(:image,:name,:description) end

and in def create add like this

def create @upload = Upload.new(upload_params) @upload.user_id = current_user.id respond_to do |format| if @upload.save

            format.html { redirect_to @upload, notice: 'Image was uploaded.' }
            format.json { render json: @upload, status: :created, location: @upload }

        else
            format.html { render action: "new" }
            format.json { render json: @upload.errors, status: :unprocessable_entity }
        end
    end
end

Answer 3

you should pass create parameters in controller like this

@upload = Upload.new(params[:image])

, it should be image not upload

Answer 4

This makes me think you have something invalid in your routes.rb file.

check version wise your routing syntax and all...

and check gem carrierwave version too...