【发布时间】：2014-02-18 12:10:16
【问题描述】：
我有两个模型在带有carrierwave的rails项目中使用相同的上传器
class Brand < ActiveRecord::Base
mount :avatar, AvatarUploader
end
class Profile < ActiveRecord::Base
mount :avatar, AvatarUploader
end
然后当我尝试将一个图像复制到另一个模型时
profile.avatar = brand.avatar
profile.save!
以下堆栈跟踪失败
undefined method `content_length' for nil:NilClass
usr/lib64/ruby/gems/1.9.1/gems/carrierwave-0.9.0/lib/carrierwave/storage/fog.rb:238:in `size'
/usr/lib64/ruby/gems/1.9.1/gems/carrierwave-0.9.0/lib/carrierwave/uploader/proxy.rb:57:in `size'
/usr/lib64/ruby/gems/1.9.1/gems/carrierwave-0.9.0/lib/carrierwave/sanitized_file.rb:95:in `size'
/usr/lib64/ruby/gems/1.9.1/gems/carrierwave-0.9.0/lib/carrierwave/sanitized_file.rb:135:in `empty?'
/usr/lib64/ruby/gems/1.9.1/gems/carrierwave-0.9.0/lib/carrierwave/uploader/cache.rb:119:in `cache!'
/usr/lib64/ruby/gems/1.9.1/gems/carrierwave-0.9.0/lib/carrierwave/mount.rb:327:in `cache'
/usr/lib64/ruby/gems/1.9.1/gems/carrierwave-0.9.0/lib/carrierwave/mount.rb:179:in `avatar='
/usr/lib64/ruby/gems/1.9.1/gems/carrierwave-0.9.0/lib/carrierwave/orm/activerecord.rb:38:in `avatar='
/usr/share/nginx/cranberrychic/releases/20140213171925/app/services/brand_into_user_converter.rb:42:in `copy_avatar'
/usr/share/nginx/cranberrychic/releases/20140213171925/app/services/brand_into_user_converter.rb:13:in `convert'
(irb):64:in `block (2 levels) in irb_binding'
/usr/lib64/ruby/gems/1.9.1/gems/activerecord-3.2.13/lib/active_record/connection_adapters/abstract/database_statements.rb:192:in `transaction'
/usr/lib64/ruby/gems/1.9.1/gems/activerecord-3.2.13/lib/active_record/transactions.rb:208:in `transaction'
/usr/lib64/ruby/gems/1.9.1/gems/newrelic_rpm-3.6.0.78/lib/new_relic/agent/method_tracer.rb:486:in `block in transaction_with_trace_ActiveRecord_self_name_transaction'
/usr/lib64/ruby/gems/1.9.1/gems/newrelic_rpm-3.6.0.78/lib/new_relic/agent/method_tracer.rb:235:in `trace_execution_scoped'
/usr/lib64/ruby/gems/1.9.1/gems/newrelic_rpm-3.6.0.78/lib/new_relic/agent/method_tracer.rb:481:in `transaction_with_trace_ActiveRecord_self_name_transaction'
(irb):62:in `block in irb_binding'
/usr/lib64/ruby/gems/1.9.1/gems/activerecord-3.2.13/lib/active_record/relation/delegation.rb:6:in `each'
/usr/lib64/ruby/gems/1.9.1/gems/activerecord-3.2.13/lib/active_record/relation/delegation.rb:6:in `each'
(irb):59:in `irb_binding'
/usr/lib64/ruby/1.9.1/irb/workspace.rb:80:in `eval'
/usr/lib64/ruby/1.9.1/irb/workspace.rb:80:in `evaluate'
/usr/lib64/ruby/1.9.1/irb/context.rb:254:in `evaluate'
/usr/lib64/ruby/1.9.1/irb.rb:159:in `block (2 levels) in eval_input'
/usr/lib64/ruby/1.9.1/irb.rb:273:in `signal_status'
/usr/lib64/ruby/1.9.1/irb.rb:156:in `block in eval_input'
/usr/lib64/ruby/1.9.1/irb/ruby-lex.rb:243:in `block (2 levels) in each_top_level_statement'
/usr/lib64/ruby/1.9.1/irb/ruby-lex.rb:229:in `loop'
/usr/lib64/ruby/1.9.1/irb/ruby-lex.rb:229:in `block in each_top_level_statement'
/usr/lib64/ruby/1.9.1/irb/ruby-lex.rb:228:in `catch'
/usr/lib64/ruby/1.9.1/irb/ruby-lex.rb:228:in `each_top_level_statement'
/usr/lib64/ruby/1.9.1/irb.rb:155:in `eval_input'
/usr/lib64/ruby/1.9.1/irb.rb:70:in `block in start'
/usr/lib64/ruby/1.9.1/irb.rb:69:in `catch'
/usr/lib64/ruby/1.9.1/irb.rb:69:in `start'
/usr/lib64/ruby/gems/1.9.1/gems/railties-3.2.13/lib/rails/commands/console.rb:47:in `start'
/usr/lib64/ruby/gems/1.9.1/gems/railties-3.2.13/lib/rails/commands/console.rb:8:in `start'
/usr/lib64/ruby/gems/1.9.1/gems/railties-3.2.13/lib/rails/commands.rb:41:in `<top (required)>'
script/rails:6:in `require'
script/rails:6:in `<main>'
对我来说是带有雾存储的载波的错误，因为在使用文件存储的开发中，一切都按预期工作。当我尝试使用载波以任何可能的方式将图像从模型复制到另一个模型时，它会失败并出现相同的错误
我的carrierwave版本是0.9.0
rails 版本是 3.2.13 和 ruby 1.9.3-p327
【问题讨论】：