audiobookshelf/server/utils/parsers/parseEpubMetadata.js

110 lines
3.5 KiB
JavaScript

const Path = require('path')
const Logger = require('../../Logger')
const StreamZip = require('../../libs/nodeStreamZip')
const parseOpfMetadata = require('./parseOpfMetadata')
const { xmlToJSON } = require('../index')
/**
* Extract file from epub and return string content
*
* @param {string} epubPath
* @param {string} filepath
* @returns {Promise<string>}
*/
async function extractFileFromEpub(epubPath, filepath) {
const zip = new StreamZip.async({ file: epubPath })
const data = await zip.entryData(filepath).catch((error) => {
Logger.error(`[parseEpubMetadata] Failed to extract ${filepath} from epub at "${epubPath}"`, error)
})
const filedata = data?.toString('utf8')
await zip.close()
return filedata
}
/**
* Extract an XML file from epub and return JSON
*
* @param {string} epubPath
* @param {string} xmlFilepath
* @returns {Promise<Object>}
*/
async function extractXmlToJson(epubPath, xmlFilepath) {
const filedata = await extractFileFromEpub(epubPath, xmlFilepath)
if (!filedata) return null
return xmlToJSON(filedata)
}
/**
* Extract cover image from epub return true if success
*
* @param {string} epubPath
* @param {string} epubImageFilepath
* @param {string} outputCoverPath
* @returns {Promise<boolean>}
*/
async function extractCoverImage(epubPath, epubImageFilepath, outputCoverPath) {
const zip = new StreamZip.async({ file: epubPath })
const success = await zip.extract(epubImageFilepath, outputCoverPath).then(() => true).catch((error) => {
Logger.error(`[parseEpubMetadata] Failed to extract image ${epubImageFilepath} from epub at "${epubPath}"`, error)
return false
})
await zip.close()
return success
}
module.exports.extractCoverImage = extractCoverImage
/**
* Parse metadata from epub
*
* @param {import('../../models/Book').EBookFileObject} ebookFile
* @returns {Promise<import('./parseEbookMetadata').EBookFileScanData>}
*/
async function parse(ebookFile) {
const epubPath = ebookFile.metadata.path
Logger.debug(`Parsing metadata from epub at "${epubPath}"`)
// Entrypoint of the epub that contains the filepath to the package document (opf file)
const containerJson = await extractXmlToJson(epubPath, 'META-INF/container.xml')
// Get package document opf filepath from container.xml
const packageDocPath = containerJson.container?.rootfiles?.[0]?.rootfile?.[0]?.$?.['full-path']
if (!packageDocPath) {
Logger.error(`Failed to get package doc path in Container.xml`, JSON.stringify(containerJson, null, 2))
return null
}
// Extract package document to JSON
const packageJson = await extractXmlToJson(epubPath, packageDocPath)
if (!packageJson) {
return null
}
// Parse metadata from package document opf file
const opfMetadata = parseOpfMetadata.parseOpfMetadataJson(packageJson)
if (!opfMetadata) {
Logger.error(`Unable to parse metadata in package doc with json`, JSON.stringify(packageJson, null, 2))
return null
}
const payload = {
path: epubPath,
ebookFormat: 'epub',
metadata: opfMetadata
}
// Attempt to find filepath to cover image
const manifestFirstImage = packageJson.package?.manifest?.[0]?.item?.find(item => item.$?.['media-type']?.startsWith('image/'))
let coverImagePath = manifestFirstImage?.$?.href
if (coverImagePath) {
const packageDirname = Path.dirname(packageDocPath)
payload.ebookCoverPath = Path.posix.join(packageDirname, coverImagePath)
} else {
Logger.warn(`Cover image not found in manifest for epub at "${epubPath}"`)
}
return payload
}
module.exports.parse = parse