TopicFile Sync with ActiveStorage

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

Start by locating TopicFileSync and the TopicFile model, then inspect the ActiveStorage setup and existing database migrations. Define the SyncProgress model and migration from the fields in the issue, connect progress updates to each file download, and verify that an interrupted sync can resume while recording completed and failed files.