暂存

pkg/storage/s3.go

@@ -59,11 +59,17 @@ func NewS3Provider(cfg *config.StorageConfig) (*S3Provider, error) {
 }
 
 func (p *S3Provider) Upload(ctx context.Context, key string, reader io.Reader, contentType string) error {
+	return p.UploadWithMetadata(ctx, key, reader, contentType, nil)
+}
+
+// UploadWithMetadata 上传对象并保存用于完整性复核的 metadata。
+func (p *S3Provider) UploadWithMetadata(ctx context.Context, key string, reader io.Reader, contentType string, metadata map[string]string) error {
 	input := &s3manager.UploadInput{
 		Bucket:      aws.String(p.bucket),
 		Key:         aws.String(key),
 		Body:        reader,
 		ContentType: aws.String(contentType),
+		Metadata:    aws.StringMap(metadata),
 	}
 
 	_, err := p.uploader.UploadWithContext(ctx, input)
@@ -73,6 +79,26 @@ func (p *S3Provider) Upload(ctx context.Context, key string, reader io.Reader, c
 	return nil
 }
 
+// Stat 读取对象大小、内容类型和 metadata。
+func (p *S3Provider) Stat(ctx context.Context, key string) (*ObjectMetadata, error) {
+	result, err := p.client.HeadObjectWithContext(ctx, &s3.HeadObjectInput{
+		Bucket: aws.String(p.bucket),
+		Key:    aws.String(key),
+	})
+	if err != nil {
+		return nil, fmt.Errorf("读取对象 metadata 失败: %w", err)
+	}
+	metadata := make(map[string]string, len(result.Metadata))
+	for name, value := range result.Metadata {
+		metadata[strings.ToLower(name)] = aws.StringValue(value)
+	}
+	return &ObjectMetadata{
+		Size:        aws.Int64Value(result.ContentLength),
+		ContentType: aws.StringValue(result.ContentType),
+		Metadata:    metadata,
+	}, nil
+}
+
 func (p *S3Provider) Download(ctx context.Context, key string) (io.ReadCloser, error) {
 	input := &s3.GetObjectInput{
 		Bucket: aws.String(p.bucket),