go-epub

README

gopub

Go library for reading EPUB 2.0 and 3.0 files.

Install

go get github.com/LapisApple/go-epub

import "github.com/LapisApple/go-epub/gopub"

Quick Start

From a file path:

r, err := gopub.OpenReader("book.epub")
if err != nil {
    log.Fatal(err)
}
defer r.Close()

rf := r.Container.DefaultRendition()
fmt.Println(rf.Metadata.MainTitle().Name)
fmt.Println(rf.Metadata.Creator[0].Name)

From an io.ReaderAt (e.g. an *os.File):

f, _ := os.Open("book.epub")
defer f.Close()
fi, _ := f.Stat()

r, err := gopub.NewReader(f, fi.Size())

Iterate reading order:

for _, item := range rf.Spine.Itemrefs {
    if !item.IsLinear() {
        continue
    }
    rc, _ := item.Open()
    data, _ := io.ReadAll(rc)
    rc.Close()
    _ = data
}

Navigation:

// EPUB 3.0
if toc := rf.TOCNav(); toc != nil {
    for _, entry := range toc.Items {
        fmt.Println(entry.Link.Text, entry.Link.Href)
    }
}

// EPUB 2.0 fallback
for _, point := range rf.NCX.NavPoints {
    fmt.Println(point.NavLabel.Text, point.Content.Src)
}

Cover image:

cover, err := r.GetCover()
if err != nil {
    log.Fatal(err)
}
rc, _ := cover.Open()
defer rc.Close()

Guard against ZIP bombs:

opts := gopub.ReaderOptions{MaxFileSize: 50 << 20} // 50 MB
r, err := gopub.OpenReader("untrusted.epub", opts)

Features

• EPUB 2.0 and 3.0
• Rich metadata: refinements, file-as, role, title-type, series, series index, modified, writing mode
• EPUB 3.0 NavDoc + EPUB 2.0 NCX navigation
• Cover extraction — unwraps SVG and XHTML wrappers, falls back to EPUB 2.0 guide
• Malformed XML tolerance: invalid &, non-ASCII tag names, UTF-8 BOM
• MaxFileSize option to reject oversized files

API

Entry point	Returns	Description
OpenReader(path, ...opts)	*ReadCloser, error	Open EPUB from disk
NewReader(ra, size, ...opts)	*Reader, error	Open from io.ReaderAt

Type	Key fields / methods
Container	Rootfiles, DefaultRendition()
Rootfile	Metadata, Manifest, Spine, NCX, NavDoc, TOCNav(), ItemName(href)
Manifest	Items, Stylesheets(), Images(), Fonts()
ManifestItem	ID, HREF, MediaType, Open()
Spine	Itemrefs (SpineItem resolves to *ManifestItem)
Metadata	MainTitle(), Creator, Language, Identifier, Series, …

Legal

MIT License — Copyright © 2026 LapisApple.

Forked from github.com/taylorskalyo/goreader (epub package).
Feature inspiration from the Rust crate epub.