Rails: NameError: uninitialized constant Article::ImageUploader when using Carrierwave on rails 4.1.5

Question

I'm learning rails 4.1.5

I got this error:

2.1.1 :008 > Article
NameError: uninitialized constant Article::ImageUploader
    from /Volumes/disk0s4/www/rails/blog/app/models/article.rb:4:in `<class:Article>'
    from /Volumes/disk0s4/www/rails/blog/app/models/article.rb:1:in `<top (required)>'
    from (irb):8
    from /Users/didin/.rvm/gems/ruby-2.1.1/gems/railties-4.1.5/lib/rails/commands/console.rb:90:in `start'
    from /Users/didin/.rvm/gems/ruby-2.1.1/gems/railties-4.1.5/lib/rails/commands/console.rb:9:in `start'
    from /Users/didin/.rvm/gems/ruby-2.1.1/gems/railties-4.1.5/lib/rails/commands/commands_tasks.rb:69:in `console'
    from /Users/didin/.rvm/gems/ruby-2.1.1/gems/railties-4.1.5/lib/rails/commands/commands_tasks.rb:40:in `run_command!'
    from /Users/didin/.rvm/gems/ruby-2.1.1/gems/railties-4.1.5/lib/rails/commands.rb:17:in `<top (required)>'
    from /Volumes/disk0s4/www/rails/blog/bin/rails:8:in `<top (required)>'
    from /Users/didin/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from /Users/didin/.rvm/rubies/ruby-2.1.1/lib/ruby/2.1.0/rubygems/core_ext/kernel_require.rb:55:in `require'
    from -e:1:in `<main>'

my file: article.rb

class Article < ActiveRecord::Base    
    validates_presence_of :title, :body
    belongs_to :user
    mount_uploader :image, ImageUploader
end

I got error when running rails console

when I write a word 'Article' on the console, it raises error above, but it working fine when this line mount_uploader :image, ImageUploader at article.rb's file removed.

when that line is restored, the error comes again. so it seems the error is caused that line, but I'm not sure.

anyone can fix this, please...

thank you for reading and answer :-)

Max Rogers · Accepted Answer · 2015-01-15 09:46:53Z

71

I know this is a few months late but I stumbled across this issue myself. My solution was to paste

require 'carrierwave/orm/activerecord'

into the config/environment.rb file. Just append it at the end.

My Env: Ruby 2.1.2p95 ; Rails 4.1.7 ; Carrierwave-0.10.0

answered Jan 15, 2015 at 9:46

Max Rogers

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1 Comment

John Over a year ago

Thanks, I skipped over this while following the guide.

PGill · Accepted Answer · 2015-09-05 04:20:28Z

31

I added this to application.rb

require 'carrierwave'
require 'carrierwave/orm/activerecord'

Rails 4.2.0, Ruby 2.2.2, Carrierwave 0.10.0

answered Sep 5, 2015 at 4:20

PGill

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2 Comments

user3720516 Over a year ago

I'd like to point out in the CarrierWave docs it says: "Make sure you are loading CarrierWave after loading your ORM, otherwise you'll need to require the relevant extension manually"

x-yuri Over a year ago

First line is most likely not needed. It gets executed as part of Bundler.require(*Rails.groups) line.

alexey_the_cat · Accepted Answer · 2017-03-17 18:56:48Z

27

Ill put it here, just in case..

IF you are using spring gem then you have to "restart" it by changing config/application.rb or close and open terminal, or: $ bin/spring stop

You can inspect its processes lifetime here(scroll to right):

$ ps aux | grep spring
alexey           55936   0.0  0.9  2645908  78440   ??  Ss   Thu06PM   0:13.17 spring app    | myapp | started 26 hours ago | development mode
alexey           81963   0.0  0.0  2481764   1608   ??  S    Sat11PM   0:01.91 spring server | myapp | started 141 hours ago

And kill it if needed.

More info at: https://github.com/rails/spring

answered Mar 17, 2017 at 18:56

alexey_the_cat

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3 Comments

Baxter Lopez Over a year ago

Adding spaces to config/application.rb and saving worked for me!

Kevin Grant Over a year ago

Worth noting, I tried restarting the server, and guard, but modifying the application.rb file did it for me (whitespace). I never tried restarting terminal, but now I'n guessing that also would have done it.

Promise Preston Over a year ago

Just stopping spring gem using bin/spring stop did it for me. Thanks.

hungmi · Accepted Answer · 2016-03-11 06:36:44Z

10

Are you using spring?

I got two terminal windows, one for server, the other for console.

After I restarted my server and enter console again, the error disappeared.

And I didn't add any line in application.rb

Rails 4.2.4, Ruby 2.3.0, Carrierwave 0.10.0 a2c93fe

answered Mar 11, 2016 at 6:36

hungmi

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Comments

Maki · Accepted Answer · 2014-12-02 14:20:57Z

4

I'm assuming you're using CarrierWave gem for file uploads. Have you checked that it was properly installed? You could issue the command to check:

bundle show carrierwave

In my case, I've bundle installed on a different terminal where I ran rails console. HTH!

answered Dec 2, 2014 at 14:20

Maki

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Comments

Adam Kalnas · Accepted Answer · 2015-04-27 18:27:42Z

3

Another tip try: Open up the uploaded that was just generated. Ensure the name of the uploader class matches the name of the class you added in your model.

answered Apr 27, 2015 at 18:27

Adam Kalnas

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Artur79 · Accepted Answer · 2018-03-08 14:37:01Z

2

If error appears in rails app' specs only you may be missing

require 'rails_helper'

at the top :)

answered Mar 8, 2018 at 14:37

Artur79

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Comments

Seralto · Accepted Answer · 2015-09-10 18:31:02Z

1

Exit and start your console again. In this case just reload! won't solve.

answered Sep 10, 2015 at 18:31

Seralto

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Comments

John Doe · Accepted Answer · 2018-06-02 19:55:54Z

1

In my case I forgot to run rails g uploader image. Once done, it works fine.

answered Jun 2, 2018 at 19:55

John Doe

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Jerome · Accepted Answer · 2021-06-11 17:21:32Z

1

I was getting this error and then it worked after restarting the server.

This occurs rather frequently. In development, the error crops up. The uploader was probably just added. Removing spring resolves, but that is a band-aid. The simple server re-start is often the proper solution.

edited Jun 11, 2021 at 17:21

Jerome

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answered Jul 2, 2017 at 14:50

GraySmith00

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Bacho sh · Accepted Answer · 2017-12-28 11:31:05Z

0

try this in appliccation.rb correct module name this fix same problem for me

module CorrectName #OldName  <---------------
     # Do not swallow errors in after_commit/after_rollback callbacks.
    config.active_record.raise_in_transactional_callbacks = true
  end
end

answered Dec 28, 2017 at 11:31

Bacho sh

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Aniket Tiwari · Accepted Answer · 2019-09-08 17:00:46Z

0

For me, I uninstalled both the below gems

gem 'spring'
gem 'spring-watcher-listen', '~> 2.0.0'

answered Sep 8, 2019 at 17:00

Aniket Tiwari

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Feber Castellon · Accepted Answer · 2020-03-03 15:48:59Z

0

In my case in my 'user.rb' module file, I had added the following lines:

  mount_uploader :photo, PhotoUploader
  mount_uploader :coverimage, CoverimageUploader

I had to quit them and

answered Mar 3, 2020 at 15:48

Feber Castellon

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Attila Györffy · Accepted Answer · 2022-03-07 19:50:23Z

0

For anyone who has a preloader, such as Spring in place, before uninstalling the otherwise useful preloaded that speeds up your app, it's worth stopping it so that load paths will be reinitialised and any uploader in app/uploaders will be loaded once a new console or a rails process start. Try bin/spring stop. It will restart once it's necessary, now with the uploaders in place.

answered Mar 7, 2022 at 19:50

Attila Györffy

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