rails4，carrierwave上传文件名太长

Question

I'm uploading image using carrierwave remote_url.

info.remote_image_url = "IMG_URL_HOST/IMG_PAHT/IMG_NAME"

Return error message is

Errno::ENAMETOOLONG: File name too long @ rb_sysopen
- /Users/kai/rails/rails_pjt/public/uploads/tmp/1421373782-65124-7719/D-__E1_84_8B_E1_85_A1_E1_86_AB_E1_84_8C_E1_85_B5_E1_84_8B_E1_85_A7_E1_86_AB__E1_84_82_E1_85_A1_E1_86_AF_E1_84_8D_E1_85_A1_E1_84_87_E1_85_A7_E1_86_AF_E1_84_8B_E1_85_A5_E1_86_B8_E1_84_86_E1_85_AE_0423__E1_84_8B_E1_85_A9_E1_84_85_E1_85_B3_E1_84_89_E1_85_A5_E1_86_BC_E1_84_92_E1_85_A7_E1_86_BC_E1_84_8B_E1_85_AC_E1_84_80_E1_85_AA-_E1_84_80_E1_85_AE_E1_86_BA_E1_84_83_E1_85_A1_E1_86_A8__E1_84_87_E1_85_A9_E1_86_AF_E1_84_85_E1_85_B2_E1_86_B7_E1_84_8C_E1_85_B5_E1_84_87_E1_85_A1_E1_86_BC_E1_84_8B_E1_85_B5_E1_84_89_E1_85_B5_E1_86_A8__E1_84_86_E1_85_A1_E1_86_AF_E1_84_84_E1_85_A9_E1_86_BC_E1_84_80_E1_85_A1_E1_84_85_E1_85_B5_orps3_landing_05.jpg from /Users/kai/.rvm/rubies/ruby-2.1.2/lib/ruby/2.1.0/fileutils.rb:1396:in `initialize'

Image file's length is 101

but after encoding UTF-8 length is 637

and them I found this solution.

http://stackoverflow.com/questions/16472894/modify-filename-before-saving-with-carrierwave

But it is different version image path

ex) file_name     : D-__E1_84_8B_E1_85_A1_E1_86_AB_E1_84.png
android_version   : android_D-__E1_84_8B_E1_85_A1_E1_86_.png
thumbnail_version : thumbnail_D-__E1_84_8B_E1_85_A1_E1_8.png

How to fix extend file name limit.

Answer 1

According to this (rejected) pull request, you can put this code into an initializer and have the issue fixed

# Monkey patch for long filenames
# @see https://github.com/carrierwaveuploader/carrierwave/pull/539/files
module CWRemoteFix

  # 255 characters is the max size of a filename in modern filesystems
  # and 100 characters are allocated for versions
  MAX_FILENAME_LENGTH = 255 - 100

  def original_filename
    filename = super
    if filename.size > MAX_FILENAME_LENGTH
      extension = (filename =~ /\./) ? filename.split(/\./).last : false
      # 32 for MD5 and 2 for the __ separator
      split_position = MAX_FILENAME_LENGTH - 32 - 2
      # +1 for the . in the extension
      split_position -= (extension.size + 1) if extension
      # Generate an hash from original filename
      hex = Digest::MD5.hexdigest(filename[split_position, filename.size])
      # Create a new name within given limits
      filename = filename[0, split_position] + '__' + hex
      filename << '.' + extension if extension
    end
    # Return original or patched filename
    filename
  end

end

# Monkeypatch downloader class using prepend
CarrierWave::Uploader::Download::RemoteFile.prepend CWRemoteFix

This patch will rename the file as <prefix-from-original-filename>__<md5-of-original-filename>.<extension-if-present>