Paperclip::Errors::MissingRequiredValidatorError - ruby-on-rails

Question

Sorry, but i cant found solution for my situation
I have next code:
class Document < ActiveRecord::Base
has_attached_file :item,
content_type: { content_type: ["image/jpeg", "image/gif", "document/pdf"] }
end
gemfile:
source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.2.1'
# Use sqlite3 as the database for Active Record
gem 'sqlite3'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 5.0'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .coffee assets and views
gem 'coffee-rails', '~> 4.1.0'
# See https://github.com/rails/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Turbolinks makes following links in your web application faster. Read more: https://github.com/rails/turbolinks
gem 'turbolinks'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc
gem 'bootstrap-sass'
gem 'haml'
gem "paperclip"
# Use ActiveModel has_secure_password
# gem 'bcrypt', '~> 3.1.7'
# Use Unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development
shema.db:
ActiveRecord::Schema.define(version: 20151015113219) do
create_table "documents", force: :cascade do |t|
t.string "title"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
t.string "item_file_name"
t.string "item_content_type"
t.integer "item_file_size"
t.datetime "item_updated_at"
end
end
Documentscontroller:
class DocumentsController < ApplicationController
def index
#documents = Document.order('created_at')
end
def new
#document = Document.new
end
def create
#document = Document.new(document_params)
if #document.save
flash[:success] = "The file was added!"
redirect_to root_path
else
render 'new'
end
end
private
def document_params
params.require(:document).permit(:item, :title)
end
end
When i unload new file, displaying error: Paperclip::Errors::MissingRequiredValidatorError
Full trace:
paperclip (4.3.1) lib/paperclip/attachment.rb:399:in `ensure_required_validations!'
paperclip (4.3.1) lib/paperclip/attachment.rb:99:in `assign'
paperclip (4.3.1) lib/paperclip/has_attached_file.rb:66:in `block in define_setter'
activerecord (4.2.1) lib/active_record/attribute_assignment.rb:54:in `public_send'
activerecord (4.2.1) lib/active_record/attribute_assignment.rb:54:in `_assign_attribute'
activerecord (4.2.1) lib/active_record/attribute_assignment.rb:41:in `block in assign_attributes'
actionpack (4.2.1) lib/action_controller/metal/strong_parameters.rb:183:in `each_pair'
actionpack (4.2.1) lib/action_controller/metal/strong_parameters.rb:183:in `each_pair'
activerecord (4.2.1) lib/active_record/attribute_assignment.rb:35:in `assign_attributes'
activerecord (4.2.1) lib/active_record/core.rb:559:in `init_attributes'
activerecord (4.2.1) lib/active_record/core.rb:281:in `initialize'
activerecord (4.2.1) lib/active_record/inheritance.rb:61:in `new'
activerecord (4.2.1) lib/active_record/inheritance.rb:61:in `new'
actionpack (4.2.1) lib/action_controller/metal/implicit_render.rb:4:in `send_action'
actionpack (4.2.1) lib/abstract_controller/base.rb:198:in `process_action'
actionpack (4.2.1) lib/action_controller/metal/rendering.rb:10:in `process_action'
actionpack (4.2.1) lib/abstract_controller/callbacks.rb:20:in `block in process_action'
activesupport (4.2.1) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:117:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:555:in `block (2 levels) in compile'
activesupport (4.2.1) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:505:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:92:in `_run_callbacks'
activesupport (4.2.1) lib/active_support/callbacks.rb:776:in `_run_process_action_callbacks'
activesupport (4.2.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.1) lib/abstract_controller/callbacks.rb:19:in `process_action'
actionpack (4.2.1) lib/action_controller/metal/rescue.rb:29:in `process_action'
actionpack (4.2.1) lib/action_controller/metal/instrumentation.rb:32:in `block in process_action'
activesupport (4.2.1) lib/active_support/notifications.rb:164:in `block in instrument'
activesupport (4.2.1) lib/active_support/notifications/instrumenter.rb:20:in `instrument'
activesupport (4.2.1) lib/active_support/notifications.rb:164:in `instrument'
actionpack (4.2.1) lib/action_controller/metal/instrumentation.rb:30:in `process_action'
actionpack (4.2.1) lib/action_controller/metal/params_wrapper.rb:250:in `process_action'
activerecord (4.2.1) lib/active_record/railties/controller_runtime.rb:18:in `process_action'
actionpack (4.2.1) lib/abstract_controller/base.rb:137:in `process'
actionview (4.2.1) lib/action_view/rendering.rb:30:in `process'
actionpack (4.2.1) lib/action_controller/metal.rb:196:in `dispatch'
actionpack (4.2.1) lib/action_controller/metal/rack_delegation.rb:13:in `dispatch'
actionpack (4.2.1) lib/action_controller/metal.rb:237:in `block in action'
actionpack (4.2.1) lib/action_dispatch/routing/route_set.rb:74:in `call'
actionpack (4.2.1) lib/action_dispatch/routing/route_set.rb:74:in `dispatch'
actionpack (4.2.1) lib/action_dispatch/routing/route_set.rb:43:in `serve'
actionpack (4.2.1) lib/action_dispatch/journey/router.rb:43:in `block in serve'
actionpack (4.2.1) lib/action_dispatch/journey/router.rb:30:in `each'
actionpack (4.2.1) lib/action_dispatch/journey/router.rb:30:in `serve'
actionpack (4.2.1) lib/action_dispatch/routing/route_set.rb:819:in `call'
rack (1.6.1) lib/rack/etag.rb:24:in `call'
rack (1.6.1) lib/rack/conditionalget.rb:38:in `call'
rack (1.6.1) lib/rack/head.rb:13:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/params_parser.rb:27:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/flash.rb:260:in `call'
rack (1.6.1) lib/rack/session/abstract/id.rb:225:in `context'
rack (1.6.1) lib/rack/session/abstract/id.rb:220:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/cookies.rb:560:in `call'
activerecord (4.2.1) lib/active_record/query_cache.rb:36:in `call'
activerecord (4.2.1) lib/active_record/connection_adapters/abstract/connection_pool.rb:649:in `call'
activerecord (4.2.1) lib/active_record/migration.rb:378:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/callbacks.rb:29:in `block in call'
activesupport (4.2.1) lib/active_support/callbacks.rb:88:in `call'
activesupport (4.2.1) lib/active_support/callbacks.rb:88:in `_run_callbacks'
activesupport (4.2.1) lib/active_support/callbacks.rb:776:in `_run_call_callbacks'
activesupport (4.2.1) lib/active_support/callbacks.rb:81:in `run_callbacks'
actionpack (4.2.1) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/reloader.rb:73:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/remote_ip.rb:78:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/debug_exceptions.rb:17:in `call'
web-console (2.1.2) lib/web_console/middleware.rb:29:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
railties (4.2.1) lib/rails/rack/logger.rb:38:in `call_app'
railties (4.2.1) lib/rails/rack/logger.rb:20:in `block in call'
activesupport (4.2.1) lib/active_support/tagged_logging.rb:68:in `block in tagged'
activesupport (4.2.1) lib/active_support/tagged_logging.rb:26:in `tagged'
activesupport (4.2.1) lib/active_support/tagged_logging.rb:68:in `tagged'
railties (4.2.1) lib/rails/rack/logger.rb:20:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/request_id.rb:21:in `call'
rack (1.6.1) lib/rack/methodoverride.rb:22:in `call'
rack (1.6.1) lib/rack/runtime.rb:18:in `call'
activesupport (4.2.1) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
rack (1.6.1) lib/rack/lock.rb:17:in `call'
actionpack (4.2.1) lib/action_dispatch/middleware/static.rb:113:in `call'
rack (1.6.1) lib/rack/sendfile.rb:113:in `call'
railties (4.2.1) lib/rails/engine.rb:518:in `call'
railties (4.2.1) lib/rails/application.rb:164:in `call'
rack (1.6.1) lib/rack/lock.rb:17:in `call'
rack (1.6.1) lib/rack/content_length.rb:15:in `call'
rack (1.6.1) lib/rack/handler/webrick.rb:89:in `service'
/usr/local/rvm/rubies/ruby-2.2.1/lib/ruby/2.2.0/webrick/httpserver.rb:138:in `service'
/usr/local/rvm/rubies/ruby-2.2.1/lib/ruby/2.2.0/webrick/httpserver.rb:94:in `run'
/usr/local/rvm/rubies/ruby-2.2.1/lib/ruby/2.2.0/webrick/server.rb:294:in `block in start_thread'

Answer 1

Form the paperclip 4.0 onwards validating the attachment content type is mandatory. So please add the validation logic in your model to work.
class Document < ActiveRecord::Base
has_attached_file :item
validates_attachment_content_type :item, :content_type => ["image/jpg", "image/jpeg", "image/png", "image/gif", "application/pdf"]
end

Answer 2

Specify a version lower than 4.0 for paperclip fixed for me, you can try that