init: 提交 files 服务初始代码

Co-authored-by: Cursor <cursoragent@cursor.com>

internal/storage/object.go

@@ -0,0 +1,76 @@
+package storage
+
+import (
+	"context"
+	"fmt"
+	"strings"
+	"time"
+
+	"github.com/aliyun/alibabacloud-oss-go-sdk-v2/oss"
+)
+
+type ObjectInfo struct {
+	Size         int64
+	ETag         string
+	LastModified time.Time
+}
+
+func (c *Client) Stat(ctx context.Context, objectKey string) (ObjectInfo, error) {
+	if strings.TrimSpace(objectKey) == "" {
+		return ObjectInfo{}, fmt.Errorf("对象键不能为空")
+	}
+
+	result, err := c.client.GetObjectMeta(ctx, &oss.GetObjectMetaRequest{
+		Bucket: oss.Ptr(c.bucket),
+		Key:    oss.Ptr(objectKey),
+	})
+	if err != nil {
+		return ObjectInfo{}, fmt.Errorf("查询对象元数据: %w", err)
+	}
+	if result == nil {
+		return ObjectInfo{}, fmt.Errorf("对象元数据为空")
+	}
+	if result.ContentLength < 0 {
+		return ObjectInfo{}, fmt.Errorf("对象大小无效: %d", result.ContentLength)
+	}
+	if result.ETag == nil {
+		return ObjectInfo{}, fmt.Errorf("对象 ETag 缺失")
+	}
+	etag := strings.TrimSpace(strings.Trim(strings.TrimSpace(*result.ETag), "\""))
+	if etag == "" {
+		return ObjectInfo{}, fmt.Errorf("对象 ETag 无效")
+	}
+	if result.LastModified == nil || result.LastModified.IsZero() {
+		return ObjectInfo{}, fmt.Errorf("对象最后修改时间缺失")
+	}
+
+	return ObjectInfo{
+		Size:         result.ContentLength,
+		ETag:         etag,
+		LastModified: *result.LastModified,
+	}, nil
+}
+
+func (c *Client) Delete(ctx context.Context, objectKey string) error {
+	if strings.TrimSpace(objectKey) == "" {
+		return fmt.Errorf("对象键不能为空")
+	}
+
+	_, err := c.client.DeleteObject(ctx, &oss.DeleteObjectRequest{
+		Bucket: oss.Ptr(c.bucket),
+		Key:    oss.Ptr(objectKey),
+	})
+	if err != nil {
+		return fmt.Errorf("删除对象: %w", err)
+	}
+
+	return nil
+}
+
+func (c *Client) PublicURL(objectKey string) string {
+	return strings.TrimRight(c.publicBaseURL, "/") + "/" + strings.TrimLeft(objectKey, "/")
+}
+
+func (c *Client) Bucket() string {
+	return c.bucket
+}