filebrowser/http/preview.go
2020-06-06 18:55:01 +08:00

127 lines
2.7 KiB
Go

package http
import (
"bytes"
"errors"
"fmt"
"github.com/filebrowser/filebrowser/v2/files"
"github.com/nfnt/resize"
"image"
"image/gif"
"image/jpeg"
"image/png"
"io"
"mime"
"net/http"
"net/url"
)
var compressHandler = withUser(func(w http.ResponseWriter, r *http.Request, d *data) (int, error) {
if !d.user.Perm.Download {
return http.StatusAccepted, nil
}
file, err := files.NewFileInfo(files.FileOptions{
Fs: d.user.Fs,
Path: r.URL.Path,
Modify: d.user.Perm.Modify,
Expand: true,
Checker: d,
})
if err != nil {
return errToStatus(err), err
}
if file.IsDir || file.Type != "image" {
return http.StatusNotFound, nil
}
return compressFileHandler(w, r, file)
})
func compressFileHandler(w http.ResponseWriter, r *http.Request, file *files.FileInfo) (int, error) {
fd, err := file.Fs.Open(file.Path)
if err != nil {
return http.StatusInternalServerError, err
}
defer fd.Close()
if r.URL.Query().Get("inline") == "true" {
w.Header().Set("Content-Disposition", "inline")
} else {
// As per RFC6266 section 4.3
w.Header().Set("Content-Disposition", "attachment; filename*=utf-8''"+url.PathEscape(file.Name))
}
buf, err := compressImageHandler(file, fd)
if err != nil {
return errToStatus(err), err
}
w.Header().Add("Content-Length", fmt.Sprintf("%d", buf.Len()))
w.Header().Add("Content-Type", mime.TypeByExtension(file.Extension))
io.Copy(w, buf)
return 0, nil
}
func compressImageHandler(file *files.FileInfo, fd io.Reader) (*bytes.Buffer, error) {
var (
buf *bytes.Buffer
m image.Image
err error
)
switch file.Extension {
case ".jpg", ".jpeg":
buf, m, err = compressImage(jpeg.Decode, fd)
if err != nil {
return nil, err
}
err = jpeg.Encode(buf, m, nil)
break
case ".png":
buf, m, err = compressImage(png.Decode, fd)
if err != nil {
return nil, err
}
err = png.Encode(buf, m)
break
case ".gif":
buf, m, err = compressImage(gif.Decode, fd)
if err != nil {
return nil, err
}
err = gif.Encode(buf, m, nil)
break
default:
return nil, errors.New("extension is not supported")
}
if err != nil {
return nil, err
}
return buf, nil
}
const maxSize = 1080
func compressImage(decode func(r io.Reader) (image.Image, error), fd io.Reader) (*bytes.Buffer, image.Image, error) {
img, err := decode(fd)
if err != nil {
return nil, nil, err
}
buf := bytes.NewBuffer([]byte{})
width := img.Bounds().Dx()
height := img.Bounds().Dy()
if width > maxSize && width > height {
width = maxSize
height = 0
} else if height > maxSize && height > width {
width = 0
height = maxSize
} else {
width = 0
height = 0
}
m := resize.Resize(uint(width), uint(height), img, resize.Lanczos3)
return buf, m, nil
}