1 files changed, 96 insertions, 0 deletions
diff --git a/internal/media/metadata.go b/internal/media/metadata.go
new file mode 100644
index 000000000..3816b2826
--- /dev/null
+++ b/internal/media/metadata.go
@@ -0,0 +1,96 @@
+// 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 {
+			return err
+		}
+	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)
+	}
+
+	// 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)
+	}
+
+	// Terminate EXIF data from 'inFile' -> 'outFile'.
+	err = terminator.TerminateInto(outFile, inFile, ext)
+	if err != nil {
+		return gtserror.Newf("error terminating exif data: %w", err)
+	}
+
+	// Done with files.
+	_ = inFile.Close()
+	_ = outFile.Close()
+
+	return nil
+}