ファイル
btrc-hub/backend/app/services/material_thumbnail_generator.rb
T
2026-06-26 00:21:33 +09:00

127 行
3.3 KiB
Ruby

# frozen_string_literal: true
require 'mini_magick'
require 'open3'
require 'tempfile'
class MaterialThumbnailGenerator
SIZE = '180x180'
class << self
def generate! material
new(material).generate!
end
end
def initialize material
@material = material
@ffmpeg_stderr = []
end
def generate!
return log_result(:no_file) unless @material.file.attached?
return log_result(:unsupported_content_type) unless image? || video?
@material.file.blob.open do |file|
thumbnail = image? ? image_thumbnail(file.path) : video_thumbnail(file.path)
return log_result(:generation_failed) unless thumbnail
return attach_thumbnail(thumbnail)
end
rescue ActiveStorage::FileNotFoundError => e
log_result(:file_not_found, error: e)
rescue MiniMagick::Error => e
log_result(:mini_magick_error, error: e)
rescue ArgumentError, StandardError => e
log_result(:generation_failed, error: e)
end
private
def image? = content_type.start_with?('image/')
def video? = content_type.start_with?('video/')
def content_type
return nil unless @material.file.attached?
@material.file.blob.content_type.to_s
end
def image_thumbnail path
image = MiniMagick::Image.open(path)
image.resize(SIZE)
image.format('jpg')
image
end
def video_thumbnail path
[1, 0].each do |seconds|
tempfile = Tempfile.new(['material-thumbnail', '.jpg'])
tempfile.close
ok = extract_video_frame(path, tempfile.path, seconds)
next unless ok && File.size?(tempfile.path)
return image_thumbnail(tempfile.path)
ensure
tempfile&.unlink
end
nil
end
def extract_video_frame input_path, output_path, seconds
_stdout, stderr, status =
Open3.capture3('ffmpeg',
'-y',
'-ss', seconds.to_s,
'-i', input_path,
'-frames:v', '1',
'-f', 'image2',
output_path)
@ffmpeg_stderr << stderr if stderr.present?
status.success?
rescue Errno::ENOENT => e
@ffmpeg_stderr << "ffmpeg unavailable: #{ e.message }"
false
end
def attach_thumbnail image
blob = nil
File.open(image.path) do |io|
blob = ActiveStorage::Blob.create_and_upload!(
io:,
filename: 'material-thumbnail.jpg',
content_type: 'image/jpeg')
end
@material.thumbnail.attach(blob)
log_result(:attached)
rescue StandardError => e
blob&.purge_later
log_result(:attach_failed, error: e)
end
def log_result result, error: nil
log_payload = { material_id: @material.id,
file_blob_id: file_blob_id,
content_type:,
result:,
error_class: error&.class&.name,
error_message: error&.message,
ffmpeg_stderr: @ffmpeg_stderr.join("\n").presence }
if [:attached, :no_file, :unsupported_content_type].include?(result)
Rails.logger.info("Material thumbnail generation: #{ log_payload.to_json }")
else
Rails.logger.warn("Material thumbnail generation: #{ log_payload.to_json }")
end
result
end
def file_blob_id
return nil unless @material.file.attached?
@material.file.blob.id
end
end