class TitreIdentiteWatermarkJob < ApplicationJob class FileNotScannedYetError < StandardError end # If by the time the job runs the blob has been deleted, ignore the error discard_on ActiveRecord::RecordNotFound # If the file is deleted during the scan, ignore the error discard_on ActiveStorage::FileNotFoundError # If the file is not analyzed or scanned for viruses yet, retry later # (to avoid modifying the file while it is being scanned). retry_on FileNotScannedYetError, wait: :exponentially_longer, attempts: 10 MAX_IMAGE_SIZE = 1500 SCALE = 0.9 WATERMARK = URI.parse(WATERMARK_FILE).is_a?(URI::HTTP) ? WATERMARK_FILE : Rails.root.join("app/assets/images/#{WATERMARK_FILE}") def perform(blob) if blob.virus_scanner.pending? then raise FileNotScannedYetError end if blob.watermark_done? then return end blob.open do |file| watermark = resize_watermark(file) if watermark.present? processed = watermark_image(file, watermark) blob.metadata[:watermark] = true blob.upload(processed) blob.save else blob.metadata[:watermark_invalid] = true blob.save end end end private def watermark_image(file, watermark) ImageProcessing::MiniMagick .source(file) .convert("png") .resize_to_limit(MAX_IMAGE_SIZE, MAX_IMAGE_SIZE) .composite(watermark, mode: "over", gravity: "center") .call end def resize_watermark(file) metadata = image_metadata(file) if metadata[:width].present? && metadata[:height].present? width = [metadata[:width], MAX_IMAGE_SIZE].min * SCALE height = [metadata[:height], MAX_IMAGE_SIZE].min * SCALE diagonal = Math.sqrt(height**2 + width**2) angle = Math.asin(height / diagonal) * 180 / Math::PI ImageProcessing::MiniMagick .source(WATERMARK) .resize_to_limit(diagonal, diagonal / 2) .rotate(-angle, background: :transparent) .call end end def image_metadata(file) read_image(file) do |image| if rotated_image?(image) { width: image.height, height: image.width } else { width: image.width, height: image.height } end end end def read_image(file) require "mini_magick" image = MiniMagick::Image.new(file.path) if image.valid? yield image else logger.info "Skipping image analysis because ImageMagick doesn't support the file" {} end end def rotated_image?(image) ['RightTop', 'LeftBottom'].include?(image["%[orientation]"]) end end