import * as CFI from './epubcfi.js'
const NS = {
CONTAINER: 'urn:oasis:names:tc:opendocument:xmlns:container',
XHTML: 'http://www.w3.org/1999/xhtml',
OPF: 'http://www.idpf.org/2007/opf',
EPUB: 'http://www.idpf.org/2007/ops',
DC: 'http://purl.org/dc/elements/1.1/',
DCTERMS: 'http://purl.org/dc/terms/',
ENC: 'http://www.w3.org/2001/04/xmlenc#',
NCX: 'http://www.daisy.org/z3986/2005/ncx/',
XLINK: 'http://www.w3.org/1999/xlink',
SMIL: 'http://www.w3.org/ns/SMIL',
}
const MIME = {
XML: 'application/xml',
NCX: 'application/x-dtbncx+xml',
XHTML: 'application/xhtml+xml',
HTML: 'text/html',
CSS: 'text/css',
SVG: 'image/svg+xml',
JS: /\/(x-)?(javascript|ecmascript)/,
}
// convert to camel case
const camel = x => x.toLowerCase().replace(/[-:](.)/g, (_, g) => g.toUpperCase())
// strip and collapse ASCII whitespace
// https://infra.spec.whatwg.org/#strip-and-collapse-ascii-whitespace
const normalizeWhitespace = str => str ? str
.replace(/[\t\n\f\r ]+/g, ' ')
.replace(/^[\t\n\f\r ]+/, '')
.replace(/[\t\n\f\r ]+$/, '') : ''
const filterAttribute = (attr, value, isList) => isList
? el => el.getAttribute(attr)?.split(/\s/)?.includes(value)
: typeof value === 'function'
? el => value(el.getAttribute(attr))
: el => el.getAttribute(attr) === value
const getAttributes = (...xs) => el =>
el ? Object.fromEntries(xs.map(x => [camel(x), el.getAttribute(x)])) : null
const getElementText = el => normalizeWhitespace(el?.textContent)
const childGetter = (doc, ns) => {
// ignore the namespace if it doesn't appear in document at all
const useNS = doc.lookupNamespaceURI(null) === ns || doc.lookupPrefix(ns)
const f = useNS
? (el, name) => el => el.namespaceURI === ns && el.localName === name
: (el, name) => el => el.localName === name
return {
$: (el, name) => [...el.children].find(f(el, name)),
$$: (el, name) => [...el.children].filter(f(el, name)),
$$$: useNS
? (el, name) => [...el.getElementsByTagNameNS(ns, name)]
: (el, name) => [...el.getElementsByTagName(name)],
}
}
const resolveURL = (url, relativeTo) => {
try {
// some tools (e.g., calibre) percent-encode punctuation we expect to be raw
url = url.replace(/%2c/gi, ',').replace(/%3a/gi, ':')
if (relativeTo.includes(':') && !relativeTo.startsWith('OEBPS'))
return new URL(url, relativeTo)
// the base needs to be a valid URL, so set a base URL and then remove it
const root = 'https://invalid.invalid/'
const obj = new URL(url, root + relativeTo)
obj.search = ''
return decodeURI(obj.href.replace(root, ''))
} catch (e) {
console.warn(e)
return url
}
}
const isExternal = uri => /^(?!blob)\w+:/i.test(uri)
// like `path.relative()` in Node.js
const pathRelative = (from, to) => {
if (!from) return to
const as = from.replace(/\/$/, '').split('/')
const bs = to.replace(/\/$/, '').split('/')
const i = (as.length > bs.length ? as : bs).findIndex((_, i) => as[i] !== bs[i])
return i < 0 ? '' : Array(as.length - i).fill('..').concat(bs.slice(i)).join('/')
}
const pathDirname = str => str.slice(0, str.lastIndexOf('/') + 1)
// replace asynchronously and sequentially
// same techinque as https://stackoverflow.com/a/48032528
const replaceSeries = async (str, regex, f) => {
const matches = []
str.replace(regex, (...args) => (matches.push(args), null))
const results = []
for (const args of matches) results.push(await f(...args))
return str.replace(regex, () => results.shift())
}
const regexEscape = str => str.replace(/[-/\\^$*+?.()|[\]{}]/g, '\\$&')
const LANGS = { attrs: ['dir', 'xml:lang'] }
const ALTS = { name: 'alternate-script', many: true, ...LANGS, props: ['file-as'] }
const CONTRIB = {
many: true, ...LANGS,
props: [{ name: 'role', many: true, attrs: ['scheme'] }, 'file-as', ALTS],
setLegacyAttrs: (obj, el) => {
if (!obj.role?.length) {
const value = el.getAttributeNS(NS.OPF, 'role')
if (value) obj.role = [{ value }]
}
obj.fileAs ??= el.getAttributeNS(NS.OPF, 'file-as')
},
}
const METADATA = [
{
name: 'title', many: true, ...LANGS,
props: ['title-type', 'display-seq', 'file-as', ALTS],
},
{
name: 'identifier', many: true,
props: [{ name: 'identifier-type', attrs: ['scheme'] }],
setLegacyAttrs: (obj, el) => {
if (!obj.identifierType) {
const value = el.getAttributeNS(NS.OPF, 'scheme')
if (value) obj.identifierType = { value }
}
},
},
{ name: 'language', many: true },
{ name: 'creator', ...CONTRIB },
{ name: 'contributor', ...CONTRIB },
{ name: 'publisher', ...LANGS, props: ['file-as', ALTS] },
{ name: 'description', ...LANGS, props: [ALTS] },
{ name: 'rights', ...LANGS, props: [ALTS] },
{ name: 'date' },
{ name: 'dcterms:modified', type: 'meta' },
{
name: 'subject', many: true, ...LANGS, props: ['term', 'authority', ALTS],
setLegacyAttrs: (obj, el) => {
obj.term ??= el.getAttributeNS(NS.OPF, 'term')
obj.authority ??= el.getAttributeNS(NS.OPF, 'authority')
},
},
{ name: 'source', many: true },
{
name: 'belongs-to-collection', type: 'meta', many: true, ...LANGS,
props: [
'collection-type', 'group-position', 'dcterms:identifier', 'file-as',
ALTS, { name: 'belongs-to-collection', recursive: true },
],
},
]
const getMetadata = opf => {
const { $, $$ } = childGetter(opf, NS.OPF)
const $metadata = $(opf.documentElement, 'metadata')
const els = Array.from($metadata.children)
const getValue = (obj, el) => {
if (!el) return null
const { props = [], attrs = [] } = obj
const value = getElementText(el)
if (!props.length && !attrs.length) return value
const id = el.getAttribute('id')
const refines = id ? els.filter(filterAttribute('refines', '#' + id)) : []
const result = Object.fromEntries([['value', value]]
.concat(props.map(prop => {
const { many, recursive } = prop
const name = typeof prop === 'string' ? prop : prop.name
const filter = filterAttribute('property', name)
const subobj = recursive ? obj : prop
return [camel(name), many
? refines.filter(filter).map(el => getValue(subobj, el))
: getValue(subobj, refines.find(filter))]
}))
.concat(attrs.map(attr => [camel(attr), el.getAttribute(attr)])))
obj.setLegacyAttrs?.(result, el)
return result
}
const arr = els.filter(filterAttribute('refines', null))
const metadata = Object.fromEntries(METADATA.map(obj => {
const { type, name, many } = obj
const filter = type === 'meta'
? el => el.namespaceURI === NS.OPF && el.getAttribute('property') === name
: el => el.namespaceURI === NS.DC && el.localName === name
return [camel(name), many ? arr.filter(filter).map(el => getValue(obj, el))
: getValue(obj, arr.find(filter))]
}))
const $$meta = $$($metadata, 'meta')
const getMetasByPrefix = prefix => $$meta
.filter(filterAttribute('property', x => x?.startsWith(prefix)))
.map(el => [el.getAttribute('property').replace(prefix, ''), el])
const rendition = Object.fromEntries(getMetasByPrefix('rendition:')
.map(([k, el]) => [k, getElementText(el)]))
const media = { narrator: [], duration: {} }
for (const [k, el] of getMetasByPrefix('media:')) {
const v = getElementText(el)
if (k === 'duration') media.duration[
el.getAttribute('refines')?.split('#')?.[1] ?? ''] = parseClock(v)
else if (k === 'active-class') media.activeClass = v
else if (k === 'narrator') media.narrator.push(v)
else if (k === 'playback-active-class') media.playbackActiveClass = v
}
return { metadata, rendition, media }
}
const parseNav = (doc, resolve = f => f) => {
const { $, $$, $$$ } = childGetter(doc, NS.XHTML)
const resolveHref = href => href ? decodeURI(resolve(href)) : null
const parseLI = getType => $li => {
const $a = $($li, 'a') ?? $($li, 'span')
const $ol = $($li, 'ol')
const href = resolveHref($a?.getAttribute('href'))
const label = getElementText($a) || $a?.getAttribute('title')
// TODO: get and concat alt/title texts in content
const result = { label, href, subitems: parseOL($ol) }
if (getType) result.type = $a?.getAttributeNS(NS.EPUB, 'type')?.split(/\s/)
return result
}
const parseOL = ($ol, getType) => $ol ? $$($ol, 'li').map(parseLI(getType)) : null
const parseNav = ($nav, getType) => parseOL($($nav, 'ol'), getType)
const $$nav = $$$(doc, 'nav')
let toc = null, pageList = null, landmarks = null, others = []
for (const $nav of $$nav) {
const type = $nav.getAttributeNS(NS.EPUB, 'type')?.split(/\s/) ?? []
if (type.includes('toc')) toc ??= parseNav($nav)
else if (type.includes('page-list')) pageList ??= parseNav($nav)
else if (type.includes('landmarks')) landmarks ??= parseNav($nav, true)
else others.push({
label: getElementText($nav.firstElementChild), type,
list: parseNav($nav),
})
}
return { toc, pageList, landmarks, others }
}
const parseNCX = (doc, resolve = f => f) => {
const { $, $$ } = childGetter(doc, NS.NCX)
const resolveHref = href => href ? decodeURI(resolve(href)) : null
const parseItem = el => {
const $label = $(el, 'navLabel')
const $content = $(el, 'content')
const label = getElementText($label)
const href = resolveHref($content.getAttribute('src'))
if (el.localName === 'navPoint') {
const els = $$(el, 'navPoint')
return { label, href, subitems: els.length ? els.map(parseItem) : null }
}
return { label, href }
}
const parseList = (el, itemName) => $$(el, itemName).map(parseItem)
const getSingle = (container, itemName) => {
const $container = $(doc.documentElement, container)
return $container ? parseList($container, itemName) : null
}
return {
toc: getSingle('navMap', 'navPoint'),
pageList: getSingle('pageList', 'pageTarget'),
others: $$(doc.documentElement, 'navList').map(el => ({
label: getElementText($(el, 'navLabel')),
list: parseList(el, 'navTarget'),
})),
}
}
const parseClock = str => {
if (!str) return
const parts = str.split(':').map(x => parseFloat(x))
if (parts.length === 3) {
const [h, m, s] = parts
return h * 60 * 60 + m * 60 + s
}
if (parts.length === 2) {
const [m, s] = parts
return m * 60 + s
}
const [x, unit] = str.split(/(?=[^\d.])/)
const n = parseFloat(x)
const f = unit === 'h' ? 60 * 60
: unit === 'min' ? 60
: unit === 'ms' ? .001
: 1
return n * f
}
class MediaOverlay extends EventTarget {
#entries
#lastMediaOverlayItem
#sectionIndex
#audioIndex
#itemIndex
#audio
#volume = 1
#rate = 1
constructor(book, loadXML) {
super()
this.book = book
this.loadXML = loadXML
}
async #loadSMIL(item) {
if (this.#lastMediaOverlayItem === item) return
const doc = await this.loadXML(item.href)
const resolve = href => href ? resolveURL(href, item.href) : null
const { $, $$$ } = childGetter(doc, NS.SMIL)
this.#audioIndex = -1
this.#itemIndex = -1
this.#entries = $$$(doc, 'par').reduce((arr, $par) => {
const text = resolve($($par, 'text')?.getAttribute('src'))
const $audio = $($par, 'audio')
if (!text || !$audio) return arr
const src = resolve($audio.getAttribute('src'))
const begin = parseClock($audio.getAttribute('clipBegin'))
const end = parseClock($audio.getAttribute('clipEnd'))
const last = arr.at(-1)
if (last?.src === src) last.items.push({ text, begin, end })
else arr.push({ src, items: [{ text, begin, end }] })
return arr
}, [])
this.#lastMediaOverlayItem = item
}
get #activeAudio() {
return this.#entries[this.#audioIndex]
}
get #activeItem() {
return this.#activeAudio?.items?.[this.#itemIndex]
}
#error(e) {
console.error(e)
this.dispatchEvent(new CustomEvent('error', { detail: e }))
}
#highlight() {
this.dispatchEvent(new CustomEvent('highlight', { detail: this.#activeItem }))
}
#unhighlight() {
this.dispatchEvent(new CustomEvent('unhighlight', { detail: this.#activeItem }))
}
async #play(audioIndex, itemIndex) {
if (this.#audio) {
this.#audio.pause()
URL.revokeObjectURL(this.#audio.src)
this.#audio = null
}
this.#audioIndex = audioIndex
this.#itemIndex = itemIndex
const src = this.#activeAudio?.src
if (!src || !this.#activeItem) return this.start(this.#sectionIndex + 1)
const url = URL.createObjectURL(await this.book.loadBlob(src))
const audio = new Audio(url)
this.#audio = audio
audio.addEventListener('timeupdate', () => {
if (audio.paused) return
const t = audio.currentTime
const { items } = this.#activeAudio
if (t > this.#activeItem?.end) {
this.#unhighlight()
if (this.#itemIndex === items.length - 1) {
this.#play(this.#audioIndex + 1, 0).catch(e => this.#error(e))
return
}
}
const oldIndex = this.#itemIndex
while (items[this.#itemIndex + 1]?.begin <= t) this.#itemIndex++
if (this.#itemIndex !== oldIndex) this.#highlight()
})
audio.addEventListener('error', () =>
this.#error(new Error(`Failed to load ${src}`)))
audio.addEventListener('playing', () => this.#highlight())
audio.addEventListener('pause', () => this.#unhighlight())
audio.addEventListener('ended', () => {
this.#unhighlight()
URL.revokeObjectURL(url)
this.#audio = null
this.#play(audioIndex + 1, 0).catch(e => this.#error(e))
})
audio.addEventListener('canplaythrough', () => {
audio.currentTime = this.#activeItem.begin ?? 0
audio.volume = this.#volume
audio.playbackRate = this.#rate
audio.play().catch(e => this.#error(e))
})
}
async start(sectionIndex, filter = () => true) {
this.#audio?.pause()
const section = this.book.sections[sectionIndex]
const href = section?.id
if (!href) return
const { mediaOverlay } = section
if (!mediaOverlay) return this.start(sectionIndex + 1)
this.#sectionIndex = sectionIndex
await this.#loadSMIL(mediaOverlay)
for (let i = 0; i < this.#entries.length; i++) {
const { items } = this.#entries[i]
for (let j = 0; j < items.length; j++) {
if (items[j].text.split('#')[0] === href && filter(items[j], j, items))
return this.#play(i, j).catch(e => this.#error(e))
}
}
}
pause() {
this.#audio?.pause()
}
resume() {
this.#audio?.play().catch(e => this.#error(e))
}
prev() {
if (this.#itemIndex > 0) this.#play(this.#audioIndex, this.#itemIndex - 1)
else if (this.#audioIndex > 0) this.#play(this.#audioIndex - 1,
this.#entries[this.#audioIndex - 1].items.length - 1)
else if (this.#sectionIndex > 0)
this.start(this.#sectionIndex - 1, (_, i, items) => i === items.length - 1)
}
next() {
this.#play(this.#audioIndex, this.#itemIndex + 1)
}
setVolume(volume) {
this.#volume = volume
if (this.#audio) this.#audio.volume = volume
}
setRate(rate) {
this.#rate = rate
if (this.#audio) this.#audio.playbackRate = rate
}
}
const isUUID = /([0-9a-f]{8})-([0-9a-f]{4})-([0-9a-f]{4})-([0-9a-f]{4})-([0-9a-f]{12})/
const getUUID = opf => {
for (const el of opf.getElementsByTagNameNS(NS.DC, 'identifier')) {
const [id] = getElementText(el).split(':').slice(-1)
if (isUUID.test(id)) return id
}
return ''
}
const getIdentifier = opf => getElementText(
opf.getElementById(opf.documentElement.getAttribute('unique-identifier'))
?? opf.getElementsByTagNameNS(NS.DC, 'identifier')[0])
// https://www.w3.org/publishing/epub32/epub-ocf.html#sec-resource-obfuscation
const deobfuscate = async (key, length, blob) => {
const array = new Uint8Array(await blob.slice(0, length).arrayBuffer())
length = Math.min(length, array.length)
for (var i = 0; i < length; i++) array[i] = array[i] ^ key[i % key.length]
return new Blob([array, blob.slice(length)], { type: blob.type })
}
const WebCryptoSHA1 = async str => {
const data = new TextEncoder().encode(str)
const buffer = await globalThis.crypto.subtle.digest('SHA-1', data)
return new Uint8Array(buffer)
}
const deobfuscators = (sha1 = WebCryptoSHA1) => ({
'http://www.idpf.org/2008/embedding': {
key: opf => sha1(getIdentifier(opf)
// eslint-disable-next-line no-control-regex
.replaceAll(/[\u0020\u0009\u000d\u000a]/g, '')),
decode: (key, blob) => deobfuscate(key, 1040, blob),
},
'http://ns.adobe.com/pdf/enc#RC': {
key: opf => {
const uuid = getUUID(opf).replaceAll('-', '')
return Uint8Array.from({ length: 16 }, (_, i) =>
parseInt(uuid.slice(i * 2, i * 2 + 2), 16))
},
decode: (key, blob) => deobfuscate(key, 1024, blob),
},
})
class Encryption {
#uris = new Map()
#decoders = new Map()
#algorithms
constructor(algorithms) {
this.#algorithms = algorithms
}
async init(encryption, opf) {
if (!encryption) return
const data = Array.from(
encryption.getElementsByTagNameNS(NS.ENC, 'EncryptedData'), el => ({
algorithm: el.getElementsByTagNameNS(NS.ENC, 'EncryptionMethod')[0]
?.getAttribute('Algorithm'),
uri: el.getElementsByTagNameNS(NS.ENC, 'CipherReference')[0]
?.getAttribute('URI'),
}))
for (const { algorithm, uri } of data) {
if (!this.#decoders.has(algorithm)) {
const algo = this.#algorithms[algorithm]
if (!algo) {
console.warn('Unknown encryption algorithm')
continue
}
const key = await algo.key(opf)
this.#decoders.set(algorithm, blob => algo.decode(key, blob))
}
this.#uris.set(uri, algorithm)
}
}
getDecoder(uri) {
return this.#decoders.get(this.#uris.get(uri)) ?? (x => x)
}
}
class Resources {
constructor({ opf, resolveHref }) {
this.opf = opf
const { $, $$, $$$ } = childGetter(opf, NS.OPF)
const $manifest = $(opf.documentElement, 'manifest')
const $spine = $(opf.documentElement, 'spine')
const $$itemref = $$($spine, 'itemref')
this.manifest = $$($manifest, 'item')
.map(getAttributes('href', 'id', 'media-type', 'properties', 'media-overlay'))
.map(item => {
item.href = resolveHref(item.href)
item.properties = item.properties?.split(/\s/)
return item
})
this.spine = $$itemref
.map(getAttributes('idref', 'id', 'linear', 'properties'))
.map(item => (item.properties = item.properties?.split(/\s/), item))
this.pageProgressionDirection = $spine
.getAttribute('page-progression-direction')
this.navPath = this.getItemByProperty('nav')?.href
this.ncxPath = (this.getItemByID($spine.getAttribute('toc'))
?? this.manifest.find(item => item.mediaType === MIME.NCX))?.href
const $guide = $(opf.documentElement, 'guide')
if ($guide) this.guide = $$($guide, 'reference')
.map(getAttributes('type', 'title', 'href'))
.map(({ type, title, href }) => ({
label: title,
type: type.split(/\s/),
href: resolveHref(href),
}))
// Try to find cover image, store XHTML cover page separately
const coverCandidate = this.getItemByProperty('cover-image')
// EPUB 2 compat
?? this.getItemByID($$$(opf, 'meta')
.find(filterAttribute('name', 'cover'))
?.getAttribute('content'))
// Guide reference
?? this.getItemByHref(this.guide
?.find(ref => ref.type.includes('cover'))?.href)
// Common cover ID patterns (case-insensitive)
?? this.manifest.find(item =>
['cover', 'cover-image', 'coverimage'].includes(item.id?.toLowerCase())
&& item.mediaType?.startsWith('image/'))
// Cover in href (check multiple common patterns)
?? this.manifest.find(item => {
const href = item.href?.toLowerCase()
return href && item.mediaType?.startsWith('image/')
&& (href.includes('/cover.') || href.includes('/cover_')
|| href.endsWith('cover.jpg') || href.endsWith('cover.png')
|| href.endsWith('cover.jpeg') || href.endsWith('cover.gif'))
})
// Titlepage image (often contains cover)
?? this.manifest.find(item =>
item.id?.toLowerCase().includes('titlepage')
&& item.mediaType?.startsWith('image/'))
// Last resort: first image in manifest
?? this.manifest.find(item => item.mediaType?.startsWith('image/'))
// If cover is XHTML/HTML, store it separately for later parsing
if (coverCandidate?.mediaType?.includes('html')) {
this.coverPage = coverCandidate
this.cover = null
} else {
this.cover = coverCandidate
this.coverPage = null
}
this.cfis = CFI.fromElements($$itemref)
}
getItemByID(id) {
return this.manifest.find(item => item.id === id)
}
getItemByHref(href) {
return this.manifest.find(item => item.href === href)
}
getItemByProperty(prop) {
return this.manifest.find(item => item.properties?.includes(prop))
}
resolveCFI(cfi) {
const parts = CFI.parse(cfi)
const top = (parts.parent ?? parts).shift()
let $itemref = CFI.toElement(this.opf, top)
// make sure it's an idref; if not, try again without the ID assertion
// mainly because Epub.js used to generate wrong ID assertions
// https://github.com/futurepress/epub.js/issues/1236
if ($itemref && $itemref.nodeName !== 'idref') {
// top.at(-1).id = null
top[top.length - 1].id = null
$itemref = CFI.toElement(this.opf, top)
}
const idref = $itemref?.getAttribute('idref')
const index = this.spine.findIndex(item => item.idref === idref)
const anchor = doc => CFI.toRange(doc, parts)
return { index, anchor }
}
}
class Loader {
#cache = new Map()
#children = new Map()
#refCount = new Map()
eventTarget = new EventTarget()
allowScript = false
constructor({ loadText, loadBlob, resources }) {
this.loadText = loadText
this.loadBlob = loadBlob
this.manifest = resources.manifest
this.assets = resources.manifest
var urlParams = new URLSearchParams(window.location.search)
this.allowScript = JSON.parse(urlParams.get('style')).allowScript
// needed only when replacing in (X)HTML w/o parsing (see below)
//.filter(({ mediaType }) => ![MIME.XHTML, MIME.HTML].includes(mediaType))
}
async createURL(href, data, type, parent) {
if (!data) return ''
const detail = { name: href, data, type }
this.eventTarget.dispatchEvent(new CustomEvent('data', { detail }))
const resolvedData = await detail.data
const resolvedType = detail.type ?? type
const blob = resolvedData instanceof Blob
? resolvedData
: new Blob([resolvedData], { type: resolvedType })
detail.type = blob.type || resolvedType
detail.data = blob
const url = URL.createObjectURL(blob)
this.#cache.set(href, url)
this.#refCount.set(href, 1)
if (parent) {
const childList = this.#children.get(parent)
if (childList) childList.push(href)
else this.#children.set(parent, [href])
}
return url
}
ref(href, parent) {
const childList = this.#children.get(parent)
if (!childList?.includes(href)) {
this.#refCount.set(href, this.#refCount.get(href) + 1)
//console.log(`referencing ${href}, now ${this.#refCount.get(href)}`)
if (childList) childList.push(href)
else this.#children.set(parent, [href])
}
return this.#cache.get(href)
}
unref(href) {
if (!this.#refCount.has(href)) return
const count = this.#refCount.get(href) - 1
//console.log(`unreferencing ${href}, now ${count}`)
if (count < 1) {
//console.log(`unloading ${href}`)
URL.revokeObjectURL(this.#cache.get(href))
this.#cache.delete(href)
this.#refCount.delete(href)
// unref children
const childList = this.#children.get(href)
if (childList) while (childList.length) this.unref(childList.pop())
this.#children.delete(href)
} else this.#refCount.set(href, count)
}
// load manifest item, recursively loading all resources as needed
async loadItem(item, parents = []) {
if (!item) return null
const { href } = item
let mediaType = item.mediaType
let isScript = MIME.JS.test(mediaType)
let allow = !(isScript && !this.allowScript)
const detail = { name: href, type: mediaType, isScript, allow }
this.eventTarget.dispatchEvent(new CustomEvent('load', { detail }))
mediaType = detail.type ?? mediaType
isScript = detail.isScript ?? MIME.JS.test(mediaType)
allow = detail.allow ?? allow
if (!allow) return null
const parent = parents[parents.length - 1]
if (this.#cache.has(href)) return this.ref(href, parent)
const targetItem = mediaType === item.mediaType ? item : { ...item, mediaType }
const shouldReplace =
(isScript || [MIME.XHTML, MIME.HTML, MIME.CSS, MIME.SVG].includes(mediaType))
// prevent circular references
&& parents.every(p => p !== href)
if (shouldReplace) return this.loadReplaced(targetItem, parents)
const dataSource = detail.data ?? Promise.resolve().then(() => this.loadBlob(href))
return this.createURL(href, dataSource, mediaType, parent)
}
async loadHref(href, base, parents = []) {
if (isExternal(href)) return href
const path = resolveURL(href, base)
const item = this.manifest.find(item => item.href === path)
if (!item) {
// Fallback for non-standard EPUBs with missing manifest entries
// Try to load the resource directly if it exists
const parent = parents[parents.length - 1]
if (this.#cache.has(path)) return this.ref(path, parent)
try {
const blob = await this.loadBlob(path)
if (blob) {
// Infer media type from file extension
const ext = path.split('.').pop()?.toLowerCase()
const mediaType = ext === 'jpg' || ext === 'jpeg' ? 'image/jpeg'
: ext === 'png' ? 'image/png'
: ext === 'gif' ? 'image/gif'
: ext === 'svg' ? 'image/svg+xml'
: ext === 'webp' ? 'image/webp'
: ext === 'css' ? 'text/css'
: 'application/octet-stream'
return this.createURL(path, blob, mediaType, parent)
}
} catch (e) {
console.warn(`Failed to load resource not in manifest: ${path}`, e)
}
return href
}
return this.loadItem(item, parents.concat(base))
}
async loadReplaced(item, parents = []) {
const { href, mediaType } = item
// const parent = parents.at(-1)
const parent = parents[parents.length - 1]
const str = await this.loadText(href)
if (!str) return null
// note that one can also just use `replaceString` for everything:
// ```
// const replaced = await this.replaceString(str, href, parents)
// return this.createURL(href, replaced, mediaType, parent)
// ```
// which is basically what Epub.js does, which is simpler, but will
// break things like iframes (because you don't want to replace links)
// or text that just happen to be paths
// parse and replace in HTML
if ([MIME.XHTML, MIME.HTML, MIME.SVG].includes(mediaType)) {
let doc = new DOMParser().parseFromString(str, mediaType)
// change to HTML if it's not valid XHTML
if (mediaType === MIME.XHTML && (doc.querySelector('parsererror')
|| !doc.documentElement?.namespaceURI)) {
console.warn(doc.querySelector('parsererror')?.innerText ?? 'Invalid XHTML')
item.mediaType = MIME.HTML
doc = new DOMParser().parseFromString(str, item.mediaType)
}
// replace hrefs in XML processing instructions
// this is mainly for SVGs that use xml-stylesheet
if ([MIME.XHTML, MIME.SVG].includes(item.mediaType)) {
let child = doc.firstChild
while (child instanceof ProcessingInstruction) {
if (child.data) {
const replacedData = await replaceSeries(child.data,
/(?:^|\s*)(href\s*=\s*['"])([^'"]*)(['"])/i,
(_, p1, p2, p3) => this.loadHref(p2, href, parents)
.then(p2 => `${p1}${p2}${p3}`))
child.replaceWith(doc.createProcessingInstruction(
child.target, replacedData))
}
child = child.nextSibling
}
}
// replace hrefs (excluding anchors)
// TODO: srcset?
const replace = async (el, attr) => el.setAttribute(attr,
await this.loadHref(el.getAttribute(attr), href, parents))
for (const el of doc.querySelectorAll('link[href]')) await replace(el, 'href')
for (const el of doc.querySelectorAll('[src]')) await replace(el, 'src')
for (const el of doc.querySelectorAll('[poster]')) await replace(el, 'poster')
for (const el of doc.querySelectorAll('object[data]')) await replace(el, 'data')
for (const el of doc.querySelectorAll('[*|href]:not([href])'))
el.setAttributeNS(NS.XLINK, 'href', await this.loadHref(
el.getAttributeNS(NS.XLINK, 'href'), href, parents))
// replace inline styles
for (const el of doc.querySelectorAll('style'))
if (el.textContent) el.textContent =
await this.replaceCSS(el.textContent, href, parents)
for (const el of doc.querySelectorAll('[style]'))
el.setAttribute('style',
await this.replaceCSS(el.getAttribute('style'), href, parents))
// TODO: replace inline scripts? probably not worth the trouble
const result = new XMLSerializer().serializeToString(doc)
return this.createURL(href, result, item.mediaType, parent)
}
const result = mediaType === MIME.CSS
? await this.replaceCSS(str, href, parents)
: await this.replaceString(str, href, parents)
return this.createURL(href, result, mediaType, parent)
}
async replaceCSS(str, href, parents = []) {
const replacedUrls = await replaceSeries(str,
/url\(\s*["']?([^'"\n]*?)\s*["']?\s*\)/gi,
(_, url) => this.loadHref(url, href, parents)
.then(url => `url("${url}")`))
// apart from `url()`, strings can be used for `@import` (but why?!)
const replacedImports = await replaceSeries(replacedUrls,
/@import\s*["']([^"'\n]*?)["']/gi,
(_, url) => this.loadHref(url, href, parents)
.then(url => `@import "${url}"`))
const w = window?.innerWidth ?? 800
const h = window?.innerHeight ?? 600
return replacedImports
// unprefix as most of the props are (only) supported unprefixed
.replace(/([{\s;])-epub-/gi, '$1')
// replace vw and vh as they cause problems with layout
.replace(/(\d*\.?\d+)vw/gi, (_, d) => parseFloat(d) * w / 100 + 'px')
.replace(/(\d*\.?\d+)vh/gi, (_, d) => parseFloat(d) * h / 100 + 'px')
// This cause a bug on Safari, element with box-shadow inside a column
// get incorrectly clipped. So for now, we just remove it.
// // `page-break-*` unsupported in columns; replace with `column-break-*`
// .replace(/page-break-(after|before|inside)\s*:/gi, (_, x) =>
// `-webkit-column-break-${x}:`)
// .replace(/break-(after|before|inside)\s*:\s*(avoid-)?page/gi, (_, x, y) =>
// `break-${x}: ${y ?? ''}column`)
// Replace font-size keyword values with pixel values so they can be calculated
.replace(/font-size\s*:\s*(xx-small|x-small|small|medium|large|x-large|xx-large|xxx-large|smaller|larger)\s*([;!])/gi, (match, keyword, ending) => {
const keywordMap = {
'xx-small': '9px',
'x-small': '10px',
'small': '13px',
'medium': '16px',
'large': '18px',
'x-large': '24px',
'xx-large': '32px',
'xxx-large': '48px',
'smaller': '13px', // approximate relative value
'larger': '18px' // approximate relative value
}
return `font-size: ${keywordMap[keyword.toLowerCase()]}${ending}`
})
// If px is used as the unit of font-size, it should be converted to em and the
// number should be divided by 16
.replace(/(\d*\.?\d+)px/gi, (_, d) => `${parseFloat(d) / 16}em`)
}
// find & replace all possible relative paths for all assets without parsing
replaceString(str, href, parents = []) {
const assetMap = new Map()
const urls = this.assets.map(asset => {
// do not replace references to the file itself
if (asset.href === href) return
// href was decoded and resolved when parsing the manifest
const relative = pathRelative(pathDirname(href), asset.href)
const relativeEnc = encodeURI(relative)
const rootRelative = '/' + asset.href
const rootRelativeEnc = encodeURI(rootRelative)
const set = new Set([relative, relativeEnc, rootRelative, rootRelativeEnc])
for (const url of set) assetMap.set(url, asset)
return Array.from(set)
}).flat().filter(x => x)
if (!urls.length) return str
const regex = new RegExp(urls.map(regexEscape).join('|'), 'g')
return replaceSeries(str, regex, async match =>
this.loadItem(assetMap.get(match.replace(/^\//, '')),
parents.concat(href)))
}
unloadItem(item) {
this.unref(item?.href)
}
destroy() {
for (const url of this.#cache.values()) URL.revokeObjectURL(url)
}
}
const getHTMLFragment = (doc, id) => doc.getElementById(id)
?? doc.querySelector(`[name="${CSS.escape(id)}"]`)
const getPageSpread = properties => {
for (const p of properties) {
if (p === 'page-spread-left' || p === 'rendition:page-spread-left')
return 'left'
if (p === 'page-spread-right' || p === 'rendition:page-spread-right')
return 'right'
if (p === 'rendition:page-spread-center') return 'center'
}
}
const getDisplayOptions = doc => {
if (!doc) return null
return {
fixedLayout: getElementText(doc.querySelector('option[name="fixed-layout"]')),
openToSpread: getElementText(doc.querySelector('option[name="open-to-spread"]')),
}
}
export class EPUB {
parser = new DOMParser()
#loader
#encryption
constructor({ loadText, loadBlob, getSize, sha1 }) {
this.loadText = loadText
this.loadBlob = loadBlob
this.getSize = getSize
this.#encryption = new Encryption(deobfuscators(sha1))
}
async #loadXML(uri) {
const str = await this.loadText(uri)
if (!str) return null
const doc = this.parser.parseFromString(str, MIME.XML)
if (doc.querySelector('parsererror'))
throw new Error(`XML parsing error: ${uri}
${doc.querySelector('parsererror').innerText}`)
return doc
}
async init() {
const $container = await this.#loadXML('META-INF/container.xml')
if (!$container) throw new Error('Failed to load container file')
const opfs = Array.from(
$container.getElementsByTagNameNS(NS.CONTAINER, 'rootfile'),
getAttributes('full-path', 'media-type'))
.filter(file => file.mediaType === 'application/oebps-package+xml')
if (!opfs.length) throw new Error('No package document defined in container')
const opfPath = opfs[0].fullPath
const opf = await this.#loadXML(opfPath)
if (!opf) throw new Error('Failed to load package document')
const $encryption = await this.#loadXML('META-INF/encryption.xml')
await this.#encryption.init($encryption, opf)
this.resources = new Resources({
opf,
resolveHref: url => resolveURL(url, opfPath),
})
this.#loader = new Loader({
loadText: this.loadText,
loadBlob: uri => Promise.resolve(this.loadBlob(uri))
.then(this.#encryption.getDecoder(uri)),
resources: this.resources,
})
this.transformTarget = this.#loader.eventTarget
this.sections = this.resources.spine.map((spineItem, index) => {
const { idref, linear, properties = [] } = spineItem
const item = this.resources.getItemByID(idref)
if (!item) {
console.warn(`Could not find item with ID "${idref}" in manifest`)
return null
}
return {
id: item.href,
load: () => this.#loader.loadItem(item),
unload: () => this.#loader.unloadItem(item),
createDocument: () => this.loadDocument(item),
size: this.getSize(item.href),
cfi: this.resources.cfis[index],
linear,
pageSpread: getPageSpread(properties),
resolveHref: href => resolveURL(href, item.href),
mediaOverlay: item.mediaOverlay
? this.resources.getItemByID(item.mediaOverlay) : null,
}
}).filter(s => s)
const { navPath, ncxPath } = this.resources
if (navPath) try {
const resolve = url => resolveURL(url, navPath)
const nav = parseNav(await this.#loadXML(navPath), resolve)
this.toc = nav.toc
this.pageList = nav.pageList
this.landmarks = nav.landmarks
} catch (e) {
console.warn(e)
}
if (!this.toc && ncxPath) try {
const resolve = url => resolveURL(url, ncxPath)
const ncx = parseNCX(await this.#loadXML(ncxPath), resolve)
this.toc = ncx.toc
this.pageList = ncx.pageList
} catch (e) {
console.warn(e)
}
this.landmarks ??= this.resources.guide
const { metadata, rendition, media } = getMetadata(opf)
this.rendition = rendition
this.media = media
this.dir = this.resources.pageProgressionDirection
const displayOptions = getDisplayOptions(
await this.#loadXML('META-INF/com.apple.ibooks.display-options.xml')
?? await this.#loadXML('META-INF/com.kobobooks.display-options.xml'))
if (displayOptions) {
if (displayOptions.fixedLayout === 'true')
this.rendition.layout ??= 'pre-paginated'
if (displayOptions.openToSpread === 'false') this.sections
.find(section => section.linear !== 'no').pageSpread ??=
this.dir === 'rtl' ? 'left' : 'right'
}
this.parsedMetadata = metadata // for debugging or advanced use cases
const title = metadata?.title?.[0]
this.metadata = {
title: title?.value,
subtitle: metadata?.title?.find(x => x.titleType === 'subtitle')?.value,
sortAs: title?.fileAs,
language: metadata?.language,
identifier: getIdentifier(opf),
description: metadata?.description?.value,
publisher: metadata?.publisher?.value,
published: metadata?.date,
modified: metadata?.dctermsModified,
subject: metadata?.subject
?.filter(({ value, term }) => value || term)
?.map(({ value, term, authority }) =>
({ name: value, code: term, scheme: authority })),
rights: metadata?.rights?.value,
}
const relators = {
art: 'artist',
aut: 'author',
bkp: 'producer',
clr: 'colorist',
edt: 'editor',
ill: 'illustrator',
nrt: 'narrator',
trl: 'translator',
pbl: 'publisher',
}
const mapContributor = defaultKey => obj => {
const keys = [...new Set(obj.role?.map(({ value, scheme }) =>
(!scheme || scheme === 'marc:relators' ? relators[value] : null)
?? defaultKey))]
const value = { name: obj.value, sortAs: obj.fileAs }
return [keys?.length ? keys : [defaultKey], value]
}
metadata?.creator?.map(mapContributor('author'))
?.concat(metadata?.contributor?.map?.(mapContributor('contributor')))
?.forEach(([keys, value]) => keys.forEach(key => {
if (this.metadata[key]) this.metadata[key].push(value)
else this.metadata[key] = [value]
}))
return this
}
async loadDocument(item) {
const str = await this.loadText(item.href)
return this.parser.parseFromString(str, item.mediaType)
}
getMediaOverlay() {
return new MediaOverlay(this, this.#loadXML.bind(this))
}
resolveCFI(cfi) {
return this.resources.resolveCFI(cfi)
}
resolveHref(href) {
const [path, hash] = href.split('#')
const item = this.resources.getItemByHref(decodeURI(path))
if (!item) return null
const index = this.resources.spine.findIndex(({ idref }) => idref === item.id)
const anchor = hash ? doc => getHTMLFragment(doc, hash) : () => 0
return { index, anchor }
}
splitTOCHref(href) {
return href?.split('#') ?? []
}
getTOCFragment(doc, id) {
return doc.getElementById(id)
?? doc.querySelector(`[name="${CSS.escape(id)}"]`)
}
isExternal(uri) {
return isExternal(uri)
}
async getCover() {
const cover = this.resources?.cover
if (cover?.href) {
return new Blob([await this.loadBlob(cover.href)], { type: cover.mediaType })
}
// If cover is an XHTML/HTML page, try to extract image from it
const coverPage = this.resources?.coverPage
if (coverPage?.href) {
try {
const text = await this.loadText(coverPage.href)
const parser = new DOMParser()
const doc = parser.parseFromString(text, 'application/xhtml+xml')
// Try to find image in various ways
// 1. Look for ![]()
tags
const img = doc.querySelector('img')
if (img) {
const src = img.getAttribute('src')
if (src) {
const imgHref = resolveURL(src, coverPage.href)
const imgItem = this.resources.getItemByHref(imgHref)
if (imgItem) {
return new Blob([await this.loadBlob(imgItem.href)], { type: imgItem.mediaType })
}
}
}
// 2. Look for tags in SVG
const svgImage = doc.querySelector('image')
if (svgImage) {
const href = svgImage.getAttribute('href') || svgImage.getAttributeNS('http://www.w3.org/1999/xlink', 'href')
if (href) {
const imgHref = resolveURL(href, coverPage.href)
const imgItem = this.resources.getItemByHref(imgHref)
if (imgItem) {
return new Blob([await this.loadBlob(imgItem.href)], { type: imgItem.mediaType })
}
}
}
} catch (e) {
console.warn('Failed to extract cover from XHTML page:', e)
}
}
// Last resort: try common cover file locations outside manifest
// This handles cases like Apple Books' iTunesArtwork
const fallbackPaths = [
'iTunesArtwork', // Apple Books cover (JPEG without extension)
'cover.jpg',
'cover.jpeg',
'cover.png',
'cover.gif',
]
for (const path of fallbackPaths) {
try {
const blob = await this.loadBlob(path)
if (blob && blob.size > 0) {
// Try to detect media type from content
const type = path === 'iTunesArtwork' ? 'image/jpeg'
: path.endsWith('.png') ? 'image/png'
: path.endsWith('.gif') ? 'image/gif'
: 'image/jpeg'
return new Blob([blob], { type })
}
} catch (e) {
// File doesn't exist, continue to next fallback
}
}
return null
}
async getCalibreBookmarks() {
const txt = await this.loadText('META-INF/calibre_bookmarks.txt')
const magic = 'encoding=json+base64:'
if (txt?.startsWith(magic)) {
const json = atob(txt.slice(magic.length))
return JSON.parse(json)
}
}
destroy() {
this.#loader?.destroy()
}
}