A cheap knock off of the default validates_length_of validator, but checks the filesize of a Carrierwave attachment

README.md

Note that this validation runs both after the file is uploaded and after CarrierWave has processed the image. If your base uploader includes a filter to resize the image then the validation will be run against the resized image, not the original one that was uploaded. If this causes a problem for you, then you should avoid using a resizing filter on the base uploader and put any specific size requirements in a version instead.

So instead of this:

require 'carrierwave/processing/mini_magick'

class LogoUploader < CarrierWave::Uploader::Base
  include CarrierWave::MiniMagick

  process :quality => 80
  process :resize_to_limit => [800, 800]
  process :convert => 'png'
  
  # ...
end

Do this:

require 'carrierwave/processing/mini_magick'

class LogoUploader < CarrierWave::Uploader::Base
  include CarrierWave::MiniMagick

  process :convert => 'png'

  version :medium do
    process :quality => 80
    process :resize_to_limit => [800, 800]
  end

  # ...

end

en.yml

# config/locales/en.yml
en:
  errors:
    messages:
      wrong_size: "is the wrong size (should be %{file_size})"
      size_too_small: "is too small (should be at least %{file_size})"
      size_too_big: "is too big (should be at most %{file_size})"

file_size_validator.rb

# lib/file_size_validator.rb
# Based on: https://gist.github.com/795665

class FileSizeValidator < ActiveModel::EachValidator
  MESSAGES  = { :is => :wrong_size, :minimum => :size_too_small, :maximum => :size_too_big }.freeze
  CHECKS    = { :is => :==, :minimum => :>=, :maximum => :<= }.freeze

  DEFAULT_TOKENIZER = lambda { |value| value.split(//) }
  RESERVED_OPTIONS  = [:minimum, :maximum, :within, :is, :tokenizer, :too_short, :too_long]

  def initialize(options)
    if range = (options.delete(:in) || options.delete(:within))
      raise ArgumentError, ":in and :within must be a Range" unless range.is_a?(Range)
      options[:minimum], options[:maximum] = range.begin, range.end
      options[:maximum] -= 1 if range.exclude_end?
    end

    super
  end

  def check_validity!
    keys = CHECKS.keys & options.keys

    if keys.empty?
      raise ArgumentError, 'Range unspecified. Specify the :within, :maximum, :minimum, or :is option.'
    end

    keys.each do |key|
      value = options[key]

      unless value.is_a?(Integer) && value >= 0
        raise ArgumentError, ":#{key} must be a nonnegative Integer"
      end
    end
  end

  def validate_each(record, attribute, value)
    raise(ArgumentError, "A CarrierWave::Uploader::Base object was expected") unless value.kind_of? CarrierWave::Uploader::Base
    
    value = (options[:tokenizer] || DEFAULT_TOKENIZER).call(value) if value.kind_of?(String)

    CHECKS.each do |key, validity_check|
      next unless check_value = options[key]

      value ||= [] if key == :maximum

      value_size = value.size
      next if value_size.send(validity_check, check_value)

      errors_options = options.except(*RESERVED_OPTIONS)
      errors_options[:file_size] = help.number_to_human_size check_value

      default_message = options[MESSAGES[key]]
      errors_options[:message] ||= default_message if default_message

      record.errors.add(attribute, MESSAGES[key], errors_options)
    end
  end
  
  def help
    Helper.instance
  end

  class Helper
    include Singleton
    include ActionView::Helpers::NumberHelper
  end
end

I'm debugging the code because it's giving me undefined method '<=' for nil:NilClass), that's on the line next if value_size.send(validity_check, check_value).
The options I'm passing: validates :profile_img, file_size: {maximum: 2.megabytes.to_i}.

The following 2 lines don't make sense for me:

raise(ArgumentError, "A CarrierWave::Uploader::Base object was expected") unless value.kind_of? CarrierWave::Uploader::Base
value = (options[:tokenizer] || DEFAULT_TOKENIZER).call(value) if value.kind_of?(String)

Maybe I'm missing something, but value cannot be of type Uploader and String at the same time:

>   CarrierWave::Uploader::Base.new.kind_of? String
=> false 
> "abc".kind_of? CarrierWave::Uploader::Base
=> false 

I discovered this was caused by some coincidence: I was migrating from paperclip and some records already had uploads, so carrierwave was thinking they are valid. I'm hosting on Azure, so I used carrierwave-azure which makes an HTTP request to get the file size and returns nil, instead of 0, if the file is unavailable. The solution was to just clear the outdated values in the upload column. Maybe this helps someone in a similar situation.

Anyway, this validator is almost useless(besides making a human readable file size in the error message), as you can just use the standard Rails length validator.

Works for me the only problem is if the file is too big it ends up saving the file in my application's /uploads/tmp/ directory. Any ideas of how to avoid this from happening and delete the file?

What is the right way to set maximum file size amount for test env?
I did something like this:

file_size: { maximum: (Rails.env.test? ? 1.megabytes.to_i : 5.megabytes.to_i }

but I don't feel it's right.

@saeedSarpas: I'm thinking about this, too. Is there a way to stub the validation within the test itself?

At least, I prettified your code a little:

validates :avatar, file_size: {maximum: (Rails.env.test? ? 5 : 100).kilobytes.to_i}

Hi! I'm using carrierwave and file_size_validator
and I'm using sidekiq
and when I run "bundle exec sidekiq " in console
i see this errors
.../lib/file_size_validator.rb:5: warning: already initialized constant FileSizeValidator::MESSAGES
and the same about
FileSizeValidator::CHECKS
and ::DEFAULT_TOKENIZER
and ::RESERVED_OPTIONS

file validators gem does file validations more elegantly. It also supports validations both before and after uploads.

File geometry validator: https://gist.github.com/pioz/6b38e26c311d525fb48a

Can anyone help me resolve this error that comes up while using this validator? For some reason the value.size calls .content_length on a nil.

lib/file_size_validator.rb:47:in `block in validate_each'
NoMethodError (undefined method `content_length' for nil:NilClass):
lib/file_size_validator.rb:42:in `each'
lib/file_size_validator.rb:42:in `validate_each'

Anyone using this with multiple files upload from Carrierwave? :)

Im getting the same error as @vinayvinay

It seems that the asset was removed out of app and file_size_validator try to validate an nonexistent file.

@osnysantos I was experiencing the same error because the asset was not present (the url was broken). I added the the line next if value.present? && !(value.file.exists?) inside the validate_each loop so I don't get an exception when the file url is broken. It seems to work fine so far. If the url is broken I don't need to validate the file size.

checks.each do |key, validity_check|
      next unless check_value = options[key]

      value ||= [] if key == :maximum
      next if value.present? && !(value.file.exists?)

      value_size = value.size
      next if value_size.send(validity_check, check_value)

Hello @chrisbloom7
As we would like to use your source code present on this page, is there any chance that we can get a license for the code written by you into the following file file_size_validator.rb ? We couldn't find any.
Thank you!

Hey @pinty,

it's possible to replace it with file_validators gem mentioned above by it's author which has the MIT license.
Besides from that it's properly packaged, has specs and a dedicated issue tracker.

PS: I'm pretty sure I'm reading a document you (co-)authored 😉