Parsing and Rebuilding EPUB Files in Python: Lessons Learned from Building an AI Book Translator

Описание и применение

Построена система перевода EPUB‑книг с сохранением форматирования, используя ebooklib и lxml для парсинга и безопасной замены текста, а также пакетную обработку с LLM.

Задача

Translating EPUB books while preserving formatting, fonts, images, and structure.

Результат

The pipeline successfully translates EPUBs while maintaining formatting and structure, enabling a functional AI book translation service.

Рабочий процесс

• Load EPUB with ebooklib.read_epub
• Iterate over spine items and parse XHTML with lxml
• Handle namespaces for XPath queries
• Extract block-level text while preserving order
• Batch paragraphs for LLM translation
• Replace text in original elements without removing attributes
• Rebuild EPUB with updated content and metadata

Доказательства

We started building LectuLibre, an AI-powered book translation service, with a simple premise: users upload an EPUB or PDF, we translate it using large language models (Claude, DeepSeek), and they download a translated copy.

Источник

We settled on ebooklib for the container-level work and lxml for parsing and modifying the XHTML content.

Источник

To replace text while preserving the block-level structure, we used lxml to set the text content of each block element.

Источник