tech/tanabata
1
1
Fork 0
Code Pull Requests Actions Releases Activity

feat(backend): extract rich numeric metadata via exiftool

Browse Source 
The previous goexif reader only understood EXIF in JPEG/TIFF, so videos,
PNGs and any image without an EXIF block were stored with no metadata at
all. Shell out to exiftool instead (the same tool the prior version used),
which covers images, video and audio in one pass.

Run it with `-n` so every tag comes back as a raw numeric/machine value
(FileSize in bytes, Duration in seconds, AvgBitrate as a number) rather
than human-readable strings — the metadata is the basis for analytics, not
decoration. Temp-file artifacts (SourceFile/Directory/permissions/inode
dates) are stripped and FileName is set to the original.

content_datetime now resolves from the first real capture date in the
metadata (DateTimeOriginal, then the video CreateDate atoms), still falling
back to the import mtime. When exiftool isn't on PATH the pure-Go EXIF
reader remains as a graceful fallback.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
Masahiko AMANO
2026-06-11 20:55:23 +03:00
parent 0b0f797fae
commit 52c62b5c8d
3 changed files with 306 additions and 24 deletions
Download Patch File Download Diff File Expand all files Collapse all files
backend/internal/service/file_service.go
+13 -24
View File
@@ -13,7 +13,6 @@ import (
"github.com/gabriel-vasile/mimetype"
"github.com/google/uuid"
"github.com/rwcarlsen/goexif/exif"
"tanabata/backend/internal/domain"
"tanabata/backend/internal/port"
@@ -112,7 +111,7 @@ func NewFileService(
// Upload validates the MIME type, saves the file to storage, creates the DB
// record, and applies any initial tags — all within a single transaction.
// If ContentDatetime is nil and EXIF DateTimeOriginal is present, it is used.
// If ContentDatetime is nil and the metadata carries a capture date, it is used.
func (s *FileService) Upload(ctx context.Context, p UploadParams) (*domain.File, error) {
userID, _, _ := domain.UserFromContext(ctx)
@@ -129,10 +128,14 @@ func (s *FileService) Upload(ctx context.Context, p UploadParams) (*domain.File,
}
data := buf.Bytes()
// Extract EXIF metadata (best-effort; non-image files will error silently).
exifData, exifDatetime := extractEXIFWithDatetime(data)
// Extract rich metadata (best-effort; covers images, video and audio).
var origName string
if p.OriginalName != nil {
origName = *p.OriginalName
}
exifData, exifDatetime := extractMetadata(data, origName, p.ContentDatetimeFallback)
// Resolve content datetime: explicit > EXIF > fallback (e.g. import mtime) > zero.
// Resolve content datetime: explicit > metadata date > fallback (e.g. import mtime) > zero.
var contentDatetime time.Time
if p.ContentDatetime != nil {
contentDatetime = *p.ContentDatetime
@@ -405,7 +408,11 @@ func (s *FileService) Replace(ctx context.Context, id uuid.UUID, p UploadParams)
return nil, fmt.Errorf("FileService.Replace: read body: %w", err)
}
data := buf.Bytes()
exifData, _ := extractEXIFWithDatetime(data)
var origName string
if p.OriginalName != nil {
origName = *p.OriginalName
}
exifData, _ := extractMetadata(data, origName, nil)
if _, err := s.storage.Save(ctx, id, bytes.NewReader(data)); err != nil {
return nil, fmt.Errorf("FileService.Replace: save to storage: %w", err)
@@ -656,21 +663,3 @@ func confineToBase(base, target string) (string, error) {
}
return absTarget, nil
}
// extractEXIFWithDatetime parses EXIF from raw bytes, returning both the JSON
// representation and the DateTimeOriginal (if present). Both may be nil.
func extractEXIFWithDatetime(data []byte) (json.RawMessage, *time.Time) {
x, err := exif.Decode(bytes.NewReader(data))
if err != nil {
return nil, nil
}
b, err := x.MarshalJSON()
if err != nil {
return nil, nil
}
var dt *time.Time
if t, err := x.DateTime(); err == nil {
dt = &t
}
return json.RawMessage(b), dt
}