forked from pgaskin/BookBrowser
/
epub.go
188 lines (157 loc) · 3.94 KB
/
epub.go
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package epub
import (
"archive/zip"
"crypto/sha1"
"fmt"
"image"
_ "image/gif"
_ "image/png"
"io"
"os"
"path/filepath"
"strconv"
"github.com/geek1011/BookBrowser/booklist"
"github.com/geek1011/BookBrowser/formats"
"github.com/beevik/etree"
"github.com/pkg/errors"
"golang.org/x/tools/godoc/vfs/zipfs"
)
type epub struct {
hascover bool
book *booklist.Book
coverpath *string
}
func (e *epub) Book() *booklist.Book {
return e.book
}
func (e *epub) HasCover() bool {
return e.coverpath != nil
}
func (e *epub) GetCover() (i image.Image, err error) {
defer func() {
if r := recover(); r != nil {
err = errors.New("panic while decoding cover image")
}
}()
zr, err := zip.OpenReader(e.book.FilePath)
if err != nil {
return nil, errors.Wrap(err, "error opening epub as zip")
}
defer zr.Close()
zfs := zipfs.New(zr, "epub")
cr, err := zfs.Open(*e.coverpath)
if err != nil {
return nil, errors.Wrapf(err, "could not open cover '%s'", *e.coverpath)
}
defer cr.Close()
i, _, err = image.Decode(cr)
if err != nil {
return nil, errors.Wrap(err, "error decoding image")
}
return i, nil
}
func load(filename string) (formats.BookInfo, error) {
e := &epub{book: &booklist.Book{}, hascover: false}
f, err := os.Open(filename)
if err != nil {
return nil, err
}
fi, err := f.Stat()
if err != nil {
f.Close()
return nil, errors.Wrapf(err, "could not stat book")
}
e.book.FilePath = filename
e.book.FileSize = fi.Size()
e.book.ModTime = fi.ModTime()
s := sha1.New()
i, err := io.Copy(s, f)
if err == nil && i != fi.Size() {
err = errors.New("could not read whole file")
}
if err != nil {
f.Close()
return nil, errors.Wrap(err, "could not hash book")
}
e.book.Hash = fmt.Sprintf("%x", s.Sum(nil))
f.Close()
zr, err := zip.OpenReader(filename)
if err != nil {
return nil, errors.Wrap(err, "error opening epub as zip")
}
defer zr.Close()
zfs := zipfs.New(zr, "epub")
rsk, err := zfs.Open("/META-INF/container.xml")
if err != nil {
return nil, errors.Wrap(err, "error reading container.xml")
}
defer rsk.Close()
container := etree.NewDocument()
_, err = container.ReadFrom(rsk)
if err != nil {
return nil, errors.Wrap(err, "error parsing container.xml")
}
rootfile := ""
for _, e := range container.FindElements("//rootfiles/rootfile[@full-path]") {
rootfile = e.SelectAttrValue("full-path", "")
}
if rootfile == "" {
return nil, errors.Wrap(err, "could not find rootfile in container.xml")
}
opfdir := filepath.Dir(rootfile)
rrsk, err := zfs.Open("/" + rootfile)
if err != nil {
return nil, errors.Wrap(err, "error reading rootfile")
}
defer rrsk.Close()
opf := etree.NewDocument()
_, err = opf.ReadFrom(rrsk)
if err != nil {
return nil, errors.Wrap(err, "error parsing rootfile")
}
e.book.Title = filepath.Base(e.book.FilePath)
for _, el := range opf.FindElements("//title") {
e.book.Title = el.Text()
break
}
for _, el := range opf.FindElements("//creator") {
e.book.Author = el.Text()
break
}
for _, el := range opf.FindElements("//publisher") {
e.book.Publisher = el.Text()
break
}
for _, el := range opf.FindElements("//description") {
e.book.Description = el.Text()
break
}
for _, el := range opf.FindElements("//meta[@name='calibre:series']") {
s := el.SelectAttrValue("content", "")
e.book.Series = s
}
if e.book.Series != "" {
for _, el := range opf.FindElements("//meta[@name='calibre:series_index']") {
i, _ := strconv.ParseFloat(el.SelectAttrValue("content", "0"), 64)
e.book.SeriesIndex = i
break
}
}
for _, el := range opf.FindElements("//meta[@name='cover']") {
coverid := el.SelectAttrValue("content", "")
if coverid != "" {
for _, f := range opf.FindElements("//[@id='" + coverid + "']") {
coverPath := f.SelectAttrValue("href", "")
if coverPath != "" {
coverPath = "/" + opfdir + "/" + coverPath
e.coverpath = &coverPath
}
}
break
}
}
return e, nil
}
func init() {
formats.Register("epub", load)
}