Class: UploaderImageDimensionsValidator

Inherits:
ActiveModel::Validations::FileContentTypeValidator show all
Defined in:
app/validators/uploader_image_dimensions_validator.rb

Instance Method Summary collapse

Methods inherited from ActiveModel::Validations::FileContentTypeValidator

#mark_invalid_original

Instance Method Details

#check_validity! ⇒ Object 



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# File 'app/validators/uploader_image_dimensions_validator.rb', line 62

def check_validity!; end

#extract_image(file) ⇒ Object 



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# File 'app/validators/uploader_image_dimensions_validator.rb', line 48

def extract_image(file)
  return unless file.try(:content_type).to_s.start_with?("image")

  if uploaded_file?(file)
    Vips::Image.new_from_file(file.path)
  elsif file.is_a?(ActiveStorage::Attached) && file.blob.persisted?
    Vips::Image.new_from_buffer(file.blob.download, "")
  end
rescue ActiveStorage::FileNotFoundError, Vips::Error
  # Although the blob is persisted, the file is not available to download and analyze
  # after committing the record
  nil
end

#validate_each(record, attribute, value) ⇒ Object 



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# File 'app/validators/uploader_image_dimensions_validator.rb', line 9

def validate_each(record, attribute, value)
  begin
    values = parse_values(value)
  rescue JSON::ParserError
    record.errors.add attribute, :invalid
    return
  end

  return if values.empty?

  uploader = record.attached_uploader(attribute) || record.send(attribute)
  return unless uploader.is_a?(Decidim::ApplicationUploader)

  values.each do |val|
    validate_image_size(record, attribute, val, uploader)
  end
end

#validate_image_size(record, attribute, file, uploader) ⇒ Object 



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# File 'app/validators/uploader_image_dimensions_validator.rb', line 27

def validate_image_size(record, attribute, file, uploader)
  return unless uploader.validable_dimensions
  return if (image = extract_image(file)).blank?

  # A simple check to avoid DoS with maliciously crafted images, or just to
  # avoid reckless users that upload images with too many pixels.
  #
  # See https://hackerone.com/reports/390
  max_dimension = [image.width, image.height].max
  record.errors.add attribute, I18n.t("decidim.errors.files.file_resolution_too_large") if max_dimension > uploader.max_image_height_or_width
rescue Vips::Error
  # The error may happen because of many reasons but most commonly the image
  # exceeds the default maximum dimensions set for libvips when the image
  # fails to load.
  #
  # Note that the error can also happen because of other reasons than only
  # the image dimensions being too large. But as we do not really know the
  # reason every time, we default to that error.
  record.errors.add attribute, I18n.t("decidim.errors.files.file_cannot_be_processed")
end