unable to upload an image using the paperclip gem - ruby-on-rails

Question

having installed the latest version of paperclip , i get an error every time i try and upload an image , i can click on the upload button , select my image but when i try to create a listing/image i get error Paperclip::Errors::MissingRequiredValidatorError in ListingsController#create Paperclip::Errors::MissingRequiredValidatorError ..imagemagick installed as well
listings.controller.rb
class ListingsController < ApplicationController
before_action :set_listing, only: [:show, :edit, :update, :destroy]
# GET /listings
# GET /listings.json
def index
#listings = Listing.all
end
# GET /listings/1
# GET /listings/1.json
def show
end
# GET /listings/new
def new
#listing = Listing.new
end
# GET /listings/1/edit
def edit
end
# POST /listings
# POST /listings.json
def create
#listing = Listing.new(listing_params) **<------ERROR**
respond_to do |format|
if #listing.save
format.html { redirect_to #listing, notice: 'Listing was successfully created.' }
format.json { render action: 'show', status: :created, location: #listing }
else
format.html { render action: 'new' }
format.json { render json: #listing.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /listings/1
# PATCH/PUT /listings/1.json
def update
respond_to do |format|
if #listing.update(listing_params)
format.html { redirect_to #listing, notice: 'Listing was successfully updated.' }
format.json { head :no_content }
else
format.html { render action: 'edit' }
format.json { render json: #listing.errors, status: :unprocessable_entity }
end
end
end
# DELETE /listings/1
# DELETE /listings/1.json
def destroy
#listing.destroy
respond_to do |format|
format.html { redirect_to listings_url }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_listing
#listing = Listing.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def listing_params
params.require(:listing).permit(:name, :description, :price, :image)
end
end
listing.rb
class Listing < ActiveRecord::Base
has_attached_file :image, :styles => { :medium => "200x", :thumb => "100x100>" }, :default_url => "missing.jpg"
end
_form.html.erb
<%= form_for(#listing, :html => { :multipart => true }) do |f| %>
<% if #listing.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#listing.errors.count, "error") %> prohibited this listing from being saved:</h2>
<ul>
<% #listing.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="form-group">
<%= f.label :name %>
<%= f.text_field :name, class: "form-control" %>
</div>
<div class="form-group">
<%= f.label :description %>
<%= f.text_area :description, class: "form-control" %>
</div>
<div class="form-group">
<%= f.label :price %>
<%= f.text_field :price, class: "form-control" %>
</div>
<div class="form-group">
<%= f.label :image %>
<%= f.file_field :image, class: "form-control" %>
</div>
<div class="form-group">
<%= f.submit class: "btn btn-primary" %>
</div>
<% end %>

Answer 1

You have to add a validation of content type in your model:
validates_attachment_content_type :image, content_type: %w(image/jpeg image/jpg image/png)