ruby-on-rails - 使用 Carrierwave 保存前修改文件名

Question

我有一个 uploader ，我在其中实现了#filename 方法来获取自定义且唯一的文件名，但看起来在保存文件之前忽略了此方法(我正在使用 fog gem 上传到 rackspace)

这是上传者:

class MyImageUploader < CarrierWave::Uploader::Base
  include CarrierWave::RMagick

  ...

  def filename
    if original_filename.present?
      "#{secure_token}.#{file.path.split('.').last.downcase}"
    else
      super
    end
  end

  ...

  private

  def secure_token
    var = :"@#{mounted_as}_secure_token"
    model.instance_variable_get(var) or model.instance_variable_set(var, SecureRandom.uuid)
  end
end

这里是控制台中的一个测试(我正在测试一个大文件名的问题，我认为可以使用自定义 #filename 方法解决):

1.9.3-p392 :002 > f = File.open('/Users/myuser/Desktop/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.png')
 => #<File:/Users/myuser/Desktop/aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa.png>
1.9.3-p392 :003 > my_model_instance.image = f
Errno::ENAMETOOLONG: File name too long - /Users/myuser/app/tmp/uploads/20130509-1723-16769-8458/thumb_lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat4lolcat.png
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:1371:in `initialize'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:1371:in `open'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:1371:in `block in copy_file'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:1370:in `open'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:1370:in `copy_file'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:477:in `copy_file'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:396:in `block in cp'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:1515:in `block in fu_each_src_dest'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:1531:in `fu_each_src_dest0'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:1513:in `fu_each_src_dest'
  from /Users/myuser/.rvm/rubies/ruby-1.9.3-p392/lib/ruby/1.9.1/fileutils.rb:395:in `cp'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/sanitized_file.rb:205:in `copy_to'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/cache.rb:121:in `block in cache!'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/callbacks.rb:17:in `with_callbacks'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/cache.rb:112:in `cache!'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/versions.rb:231:in `block in cache_versions!'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/versions.rb:216:in `each'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/versions.rb:216:in `cache_versions!'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/callbacks.rb:18:in `block in with_callbacks'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/callbacks.rb:18:in `each'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/callbacks.rb:18:in `with_callbacks'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/uploader/cache.rb:112:in `cache!'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/mount.rb:315:in `cache'
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/gems/carrierwave-0.6.2/lib/carrierwave/mount.rb:173:in `image='
  from /Users/myuser/.rvm/gems/ruby-1.9.3-p392@app/bundler/gems/carrierwave-mongoid-28a9b718d42b/lib/carrierwave/mongoid.rb:39:in `image='

所以我认为我需要在保存之前修改文件名以使自定义文件名完全起作用，因为实际上文件仅在上传到 Rackspace 后才重命名(仅当文件名不是那么大时)

Answer 1

上传在缓存步骤(在本地发生)而不是在保存步骤(在雾中发生)期间爆炸。读书the source ，看起来 carrierwave 有一个你可以覆盖的方法来做到这一点:full_original_filename

如果您要解决的问题是缩短缓存的文件名，则以下方法可能有效。如果您想稍后更改该文件名，则需要使用 official solution for that此外。

MAX_FILENAME_LENGTH = 64 # arbitrary limit, your milage may vary

def full_original_filename
  filename = super

  return filename if !filename.present?

  extension = File.extname(filename)
  basename = File.basename(filename, extension)[0...MAX_FILENAME_LENGTH]
  basename + extension
end