weiro/providers/uploadfiles/exif.go

package uploadfiles

import (
	"os"
	"path/filepath"
	"strings"

	"emperror.dev/errors"
	"github.com/disintegration/imaging"
	"lmika.dev/lmika/weiro/models"
)

const (
	applicationOctetStream = "application/octet-stream"
)

var supportedRencodableImageTypes = map[string]bool{
	"image/jpeg":           true,
	"image/png":            true,
	applicationOctetStream: true,
}
var supportedReencoableExtensions = map[string]bool{
	".jpg":  true,
	".jpeg": true,
	".png":  true,
}

func (p *Provider) StripeEXIFData(site models.Site, up models.Upload) error {
	uploadFilename := p.uploadFileName(site, up)

	if !supportedRencodableImageTypes[up.MIMEType] {
		return errors.New("unsupported image format: " + up.MIMEType)
	}
	if up.MIMEType == applicationOctetStream && !supportedReencoableExtensions[filepath.Ext(uploadFilename)] {
		return errors.New("unsupported image format")
	}

	img, err := imaging.Open(uploadFilename)
	if err != nil {
		return errors.Wrap(err, "failed to open image file")
	}

	tmpName := strings.TrimSuffix(uploadFilename, filepath.Ext(uploadFilename)) + ".tmp." + filepath.Ext(uploadFilename)
	if err := imaging.Save(img, tmpName); err != nil {
		return errors.Wrap(err, "failed to save image file")
	}

	if err := os.Remove(uploadFilename); err != nil {
		_ = os.Remove(tmpName)
		return errors.Wrap(err, "failed to remove image file")
	}

	if err := os.Rename(tmpName, uploadFilename); err != nil {
		return errors.Wrap(err, "failed to rename image file")
	}

	return nil
}