Feat: cos policy upload/download in server-side

pkg/filesystem/driver/oss/handller.go

@@ -236,10 +236,21 @@ func (handler Driver) Source(
 }
 
 func (handler Driver) signSourceURL(ctx context.Context, path string, ttl int64, options []oss.Option) (string, error) {
-	// 是否带有 Version ID
-	if _, ok := ctx.Value(VersionID).(int64); ok {
-
+	cdnURL, err := url.Parse(handler.Policy.BaseURL)
+	if err != nil {
+		return "", err
 	}
+
+	// 公有空间不需要签名
+	if !handler.Policy.IsPrivate {
+		file, err := url.Parse(path)
+		if err != nil {
+			return "", err
+		}
+		sourceURL := cdnURL.ResolveReference(file)
+		return sourceURL.String(), nil
+	}
+
 	signedURL, err := handler.bucket.SignURL(path, oss.HTTPGet, ttl, options...)
 	if err != nil {
 		return "", err
@@ -250,10 +261,6 @@ func (handler Driver) signSourceURL(ctx context.Context, path string, ttl int64,
 	if err != nil {
 		return "", err
 	}
-	cdnURL, err := url.Parse(handler.Policy.BaseURL)
-	if err != nil {
-		return "", err
-	}
 	finalURL.Host = cdnURL.Host
 	finalURL.Scheme = cdnURL.Scheme