TopicFile Sync with ActiveStorage

[dmitrytrager]

Sync files and attach using ActiveStorage

  class TopicFileSync
    def sync(file_data, topic)
      topic_file = TopicFile.find_or_initialize_by(external_id: file_data["id"])

      # Skip if checksum unchanged (file hasn't changed on server)
      return topic_file if topic_file.external_checksum == file_data["checksum"]

      # Download and verify
      downloaded_path = downloader.download(file_data["id"], expected_checksum: file_data["checksum"])
      verifier.verify!(downloaded_path, file_data["checksum"])

      # Attach via ActiveStorage
      File.open(downloaded_path, "rb") do |io|
        topic_file.file.attach(
          io: io,
          filename: file_data["filename"],
          content_type: file_data["content_type"]
        )
      end

      topic_file.update!(
        topic: topic,
        filename: file_data["filename"],
        file_type: extract_file_type(file_data["content_type"]),
        file_size: file_data["size_bytes"],
        external_checksum: file_data["checksum"]
      )

      topic_file
    ensure
      FileUtils.rm_f(downloaded_path) if downloaded_path
    end
  end

Track and persist download progress for resume

• Create SyncProgress model:

create_table :sync_progress do |t|
  t.string :manifest_version
  t.string :status  # pending, downloading, completed, failed
  t.integer :total_files
  t.integer :completed_files
  t.integer :total_bytes
  t.integer :downloaded_bytes
  t.json :pending_file_ids  # files remaining to download
  t.json :failed_file_ids   # files that failed
  t.timestamps
end

• Update progress after each file download
• Use for resume after interruption/restart