carrierwave - rails 3.1- undefined method: image_will_change
I get an error that look like this:
undefined method `post_image_will_change!' for #<Post:0xf4e9184>
app/controllers/posts_controller.rb:43:in `new'
app/controllers/posts_controller.rb:43:in `create'
I've included this in my "post" model:
attr_accessible :title, :name, :content, :post_image
mount_uploader :post_image, PostImageUploader
and in _form.html.erb I've added:
:html => { :multipart => true }
I looked CarrierWave Error but that doesn't help me.
Any clues of what generates that error? I've mig开发者_开发百科rated the database and so forth (followed the railscasts guide on carrierwave exactly..)
The OP comments that he fixed it, however there's no answer set so I thought I'd add one for people coming across this in the future, which included myself until I figured it out :)
undefined method `x_will_change!' for # happens if you forget to add a column in your model's db table. If you have a model User and a AvatarUploader, with the uploader mounted as in the Carrierwave docs:
class User < ActiveRecord::Base
mount_uploader :avatar, AvatarUploader
end
Then the error will read
undefined method `avatar_will_change!' for #<User:0x00...>
To fix it (based on this example) add a column in a migration run the following in the console:
rails g migration AddAvatarToUsers avatar:string
This will generate the following migration:
class AddAvatarToUsers < ActiveRecord::Migration
def change
add_column :users, :avatar, :string
end
end
Then migrate to apply the change (again in the console):
rake db:migrate
I suppose that author just forgot to run:
rake db:migrate
ALso, if you met such error inside of your tests then you should run:
rake db:test:prepare
Also, for anyone getting this error on heroku, you need to run
heroku run rake db:migrate
and
heroku restart
in the terminal after adding/removing fields/tables from your database.
Kreek, this is obviously a minor oversight, as most people would have realized by now, you probably meant to run this command, as one should, outside the console, otherwise, one would get the following:
'NameError: undefined local variable or method `migrate' for main:Object'.
I had similar problem but mine was because I was copying and pasting codes and forgot to delete
mount_uploader :picture, PictureUploader
from my model which did not use pictures. Hope this help others in future who could not figure out what happened
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