Carrierwave - Save nil if the image is not uploaded - ruby-on-rails

Question

i am trying to migrate images from local file system to dropbox, so i am using carrierwave dropbox gem to move all images to dropbox. i am able to store new images which is uploaded from my application. I am trying to move the existing images.
i am using Article.first.avatar? method to check whether the image exists or not, i have used this method in many places for different sizes of images in my application.
when i use the above method to find out whether the image exists or not, it says true always when the image is not present in dropbox. Look at my console output(2),
My uploader:
class Avatar < CarrierWave::Uploader::Base
include CarrierWave::MiniMagick
storage: file
def store_dir
if model
"uploads/#{model.class.to_s.underscore}/#{model.id}/#{mounted_as}"
else
"uploads/#{mounted_as}/"
end
end
end
console output (1)
>Article.first.avatar?
>false
#<AvatarUploader:0x007f9813f1fe70
#file=
#<CarrierWave::SanitizedFile:0x007f9813f1e688
#content_type=nil,
#file="/Users/work/project/app1/public/uploads/370/avatar/avatar.png",
#original_filename=nil>,
#model=
##Article model
#mounted_as=:avatar,
#storage=#<CarrierWave::Storage::File:0x007f9813f1fad8 #uploader=#<AvatarUploader:0x007f9813f1fe70 ...>>,
#versions={}>
I changed uploader as follows:
class Avatar < CarrierWave::Uploader::Base
include CarrierWave::MiniMagick
storage: dropbox
def store_dir
if model
"uploads/#{model.class.to_s.underscore}/#{model.id}/#{mounted_as}"
else
"uploads/#{mounted_as}/"
end
end
end
console output(2)
>Article.first.avatar?
>true
#<AvatarUploader:0x007f8574143ee8
#file=
#<CarrierWave::Storage::Dropbox::File:0x007f8574143308
#client=
#<DropboxClient:0x007f8574143420
#root="dropbox",
#session=
#<DropboxSession:0x007f8574143498
#access_token=#<OAuthToken:0x007f8574143470 #key="123453333", #secret="22222222222">,
#consumer_key="abcdeafs",
#consumer_secret="asdfasfj",
#locale=nil,
#request_token=nil>>,
#config=
{:app_key=>"asdfasfasf",
:app_secret=>"asdfkasfksf",
:access_token=>"adfkjasfkhs",
:access_token_secret=>"aksdfkhsfksf",
:access_type=>"dropbox",
:user_id=>"292929292"},
#path="uploads/images/370/avatar.png",
#uploader=#<AvatarUploader:0x007f8574143ee8 ...>>,
#model=
#Artcle Model>,
#mounted_as=:image,
#storage=
#<CarrierWave::Storage::Dropbox:0x007f8574143c90
#config=
{:app_key=>"asdfasfasf",
:app_secret=>"asdfkasfksf",
:access_token=>"adfkjasfkhs",
:access_token_secret=>"aksdfkhsfksf",
:access_type=>"dropbox",
:user_id=>"292929292"},
#dropbox_client=
#<DropboxClient:0x007f8574143420
#root="dropbox",
#session=
why does it show "true" when the image is not present.
how can i get "false" when the image is not present in dropbox.

Answer 1

My stab in the dark is that inside Carrierwave, the normal file class it returns (sanitized file) responds to empty by checking if the file exists:
https://github.com/carrierwaveuploader/carrierwave/blob/master/lib/carrierwave/sanitized_file.rb#L144
Inside the carrierwave dropbox gem, the File class (https://github.com/robin850/carrierwave-dropbox/blob/master/lib/carrierwave/storage/dropbox.rb#L45) doesn't implement this. I'm guessing if you reopened the class and added
module CarrierWave
module Storage
class Dropbox < Abstract
class File
def empty?
# use dropbox API to get the file and check the presence here
end
end
end
end
end
It would probably work?