gotosocial/internal/media/metadata.go

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// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package media
import (
"context"
"os"
"strings"
terminator "codeberg.org/superseriousbusiness/exif-terminator"
"github.com/superseriousbusiness/gotosocial/internal/gtserror"
"github.com/superseriousbusiness/gotosocial/internal/log"
)
// clearMetadata performs our best-attempt at cleaning metadata from
// input file. Depending on file type this may perform a full EXIF clean,
// or just a clean of global container level metadata records.
func clearMetadata(ctx context.Context, filepath string) error {
var ext, outpath string
// Generate cleaned output path MAINTAINING extension.
if i := strings.IndexByte(filepath, '.'); i != -1 {
outpath = filepath[:i] + "_cleaned" + filepath[i:]
ext = filepath[i+1:]
} else {
return gtserror.New("input file missing extension")
}
switch ext {
case "jpeg", "png", "webp":
// For these few file types, we actually support
// cleaning exif data using a native Go library.
log.Debug(ctx, "cleaning with exif-terminator")
err := terminateExif(outpath, filepath, ext)
if err == nil {
// No problem.
break
}
log.Warnf(ctx, "error cleaning with exif-terminator, falling back to ffmpeg: %v", err)
fallthrough
default:
// For all other types, best-effort clean with ffmpeg.
log.Debug(ctx, "cleaning with ffmpeg -map_metadata -1")
err := ffmpegClearMetadata(ctx, outpath, filepath)
if err != nil {
return err
}
}
// Move the new output file path to original location.
if err := os.Rename(outpath, filepath); err != nil {
return gtserror.Newf("error renaming %s -> %s: %w", outpath, filepath, err)
}
return nil
}
// terminateExif cleans exif data from file at input path, into file
// at output path, exusing given file extension to determine cleaning.
func terminateExif(outpath, inpath string, ext string) error {
// Open input file at given path.
inFile, err := os.Open(inpath)
if err != nil {
return gtserror.Newf("error opening input file %s: %w", inpath, err)
}
defer inFile.Close()
// Open output file at given path.
outFile, err := os.Create(outpath)
if err != nil {
return gtserror.Newf("error opening output file %s: %w", outpath, err)
}
defer outFile.Close()
// Terminate EXIF data from 'inFile' -> 'outFile'.
err = terminator.TerminateInto(outFile, inFile, ext)
if err != nil {
return gtserror.Newf("error terminating exif data: %w", err)
}
return nil
}