/
preview.go
314 lines (292 loc) · 7.03 KB
/
preview.go
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// Copyright 2017 Łukasz Pankowski <lukpank at o2 dot pl>. All rights
// reserved. This source code is licensed under the terms of the MIT
// license. See LICENSE file for details.
package main
import (
"database/sql"
"errors"
"image"
"image/jpeg"
"io"
"io/ioutil"
"log"
"net/http"
"os"
"path/filepath"
"github.com/anthonynsimon/bild/transform"
"github.com/nfnt/resize"
"github.com/rwcarlsen/goexif/exif"
)
func (s *server) ServeImage(w http.ResponseWriter, r *http.Request) {
id, err := idFromPath(r.URL.Path, "/image/")
if err != nil {
http.Error(w, s.tr("Page not found"), http.StatusNotFound)
return
}
if filename, ok := s.ensurePreview(w, r, id, ".1"); ok {
http.ServeFile(w, r, filename)
}
}
func (s *server) ServeAPIImage(w http.ResponseWriter, r *http.Request) {
id, err := idFromPath(r.URL.Path, "/api/image/")
if err != nil {
http.Error(w, s.tr("Page not found"), http.StatusNotFound)
return
}
if _, ok := s.ensurePreview(w, r, id, ".1"); ok {
w.WriteHeader(http.StatusOK)
}
}
func (s *server) ServePreview(w http.ResponseWriter, r *http.Request) {
id, err := idFromPath(r.URL.Path, "/preview/")
if err != nil {
http.Error(w, s.tr("Page not found"), http.StatusNotFound)
return
}
if filename, ok := s.ensurePreview(w, r, id, ".2"); ok {
http.ServeFile(w, r, filename)
}
}
func (s *server) ensurePreview(w http.ResponseWriter, r *http.Request, id int64, ext string) (string, bool) {
var sha256sum string
err := s.db.db.QueryRow("SELECT sha256sum FROM images where iid=?", id).Scan(&sha256sum)
if err != nil {
if err == sql.ErrNoRows {
http.Error(w, s.tr("Page not found"), http.StatusNotFound)
return "", false
}
http.Error(w, s.tr("Internal server error"), http.StatusInternalServerError)
log.Println(err)
return "", false
}
filename := filepath.Join(s.db.previewDir, sha256sum[:3], sha256sum[3:]+ext)
if _, err := os.Stat(filename); err != nil {
if !os.IsNotExist(err) {
http.Error(w, s.tr("Internal server error"), http.StatusInternalServerError)
log.Println(err)
return "", false
}
result := make(chan error)
s.preview <- previewRequest{id, sha256sum, result}
if err = <-result; err != nil {
http.Error(w, s.tr("Internal server error"), http.StatusInternalServerError)
log.Println(err)
return "", false
}
}
return filename, true
}
type previewRequest struct {
id int64
sha256sum string
result chan<- error
}
type previewJob struct {
id int64
sha256sum string
}
type previewResult struct {
sha256sum string
err error
}
func (s *server) preparePreviews(jobs []previewJob) {
result := make(chan error)
for _, job := range jobs {
s.preview <- previewRequest{job.id, job.sha256sum, result}
if err := <-result; err != nil {
log.Printf("preview %d (%s): %v", job.id, job.sha256sum[:7], err)
}
}
}
var ErrQuit = errors.New("quit")
func (s *server) previewMaster(workersCnt int) {
m := make(map[string][]previewRequest)
q := []previewJob{}
requests := make(chan previewJob)
results := make(chan previewResult)
working := 0
for i := 0; i < workersCnt; i++ {
go s.previewWorker(results, requests)
}
addReq := func(req previewRequest) {
s := m[req.sha256sum]
if len(s) == 0 {
q = append(q, previewJob{req.id, req.sha256sum})
}
m[req.sha256sum] = append(s, req)
if len(q) > 0 && working < workersCnt {
requests <- q[0]
q = q[1:]
working++
}
}
handleResult := func(result previewResult) {
working--
for _, req := range m[result.sha256sum] {
req.result <- result.err
}
delete(m, result.sha256sum)
}
For:
for {
c := s.preview
if len(q) > 4096 {
c = nil
}
select {
case req, ok := <-c:
if !ok {
break For
}
addReq(req)
case r := <-results:
handleResult(r)
if len(q) > 0 && working < workersCnt {
requests <- q[0]
q = q[1:]
working++
}
}
}
close(requests)
for working > 0 {
handleResult(<-results)
}
for _, s := range m {
for _, req := range s {
req.result <- ErrQuit
}
}
}
func (s *server) previewWorker(results chan<- previewResult, requests <-chan previewJob) {
for req := range requests {
log.Printf("creating preview for image %d (%s)\n", req.id, req.sha256sum[:7])
results <- previewResult{req.sha256sum, s.createPreviews(req.sha256sum)}
}
}
func (s *server) createPreviews(sha256sum string) error {
dirName := filepath.Join(s.db.previewDir, sha256sum[:3])
filename := filepath.Join(dirName, sha256sum[3:])
filename1 := filename + ".1"
filename2 := filename + ".2"
exists := 0
if _, err := os.Stat(filename1); err != nil {
if !os.IsNotExist(err) {
return err
}
} else {
exists++
}
if _, err := os.Stat(filename2); err != nil {
if !os.IsNotExist(err) {
return err
}
} else {
exists++
}
if exists == 2 {
return nil
}
img, orientation, err := s.readImage(sha256sum)
if err != nil {
return err
}
if err := ensureDirExists(dirName, 0755); err != nil {
if !os.IsExist(err) {
return err
}
}
if err := s.createPreview(filename1, img, 1280, orientation); err != nil {
return err
}
return s.createPreview(filename2, img, 320, orientation)
}
func (s *server) readImage(sha256sum string) (image.Image, int, error) {
filename := filepath.Join(s.db.imagesDir, sha256sum[:3], sha256sum[3:])
f, err := os.Open(filename)
if err != nil {
return nil, 0, err
}
defer f.Close()
orientation, _ := exifOrientation(f)
if _, err := f.Seek(0, os.SEEK_SET); err != nil {
return nil, 0, err
}
img, _, err := image.Decode(f)
if err != nil {
return nil, 0, err
}
return img, orientation, f.Close()
}
func (s *server) createPreview(filename string, img image.Image, maxSize uint, orientation int) error {
var pw, ph uint
size := img.Bounds().Size()
if size.Y > size.X {
pw = 0
ph = maxSize
} else {
pw = maxSize
ph = 0
}
img = applyOrientation(resize.Resize(pw, ph, img, resize.Lanczos3), orientation)
f, err := ioutil.TempFile(s.db.uploadDir, "tmp")
if err != nil {
return err
}
tmpFileName := f.Name()
defer func() {
if tmpFileName != "" {
_ = os.Remove(tmpFileName)
}
}()
defer f.Close()
if err := jpeg.Encode(f, img, nil); err != nil {
return err
}
if err := f.Close(); err != nil {
return err
}
if err := os.Rename(tmpFileName, filename); err != nil {
return err
}
tmpFileName = ""
return nil
}
func exifOrientation(r io.Reader) (int, error) {
x, err := exif.Decode(r)
if err != nil {
return 1, err
}
o, err := x.Get("Orientation")
if err != nil {
return 1, err
}
i, err := o.Int(0)
if err != nil {
return 1, err
}
return i, nil
}
func applyOrientation(img image.Image, orientation int) image.Image {
o := &transform.RotationOptions{ResizeBounds: true, Pivot: &image.Point{0, 0}}
switch orientation {
default:
return img
case 1:
return img
case 2:
return transform.FlipH(img)
case 3:
return transform.Rotate(img, 180, o)
case 4:
return transform.FlipV(img)
case 5:
return transform.FlipH(transform.Rotate(img, 90, o))
case 6:
return transform.Rotate(img, 90, o)
case 7:
return transform.FlipH(transform.Rotate(img, -90, o))
case 8:
return transform.Rotate(img, -90, o)
}
}