feat(media-supply): integrate object storage for media supply service and enhance image upload handling

server/internal/shared/publicasset/token.go

@@ -0,0 +1,45 @@
+package publicasset
+
+import (
+	"crypto/hmac"
+	"crypto/sha256"
+	"encoding/base64"
+	"fmt"
+	"strings"
+)
+
+func SignObjectKey(objectKey string, secret string) string {
+	encodedKey := base64.RawURLEncoding.EncodeToString([]byte(objectKey))
+	mac := hmac.New(sha256.New, []byte(strings.TrimSpace(secret)))
+	_, _ = mac.Write([]byte(objectKey))
+	signature := base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
+	return fmt.Sprintf("%s.%s", encodedKey, signature)
+}
+
+func ParseObjectKeyToken(token string, secret string) (string, bool) {
+	objectKey, ok := ObjectKeyFromToken(token)
+	if !ok {
+		return "", false
+	}
+	expected := SignObjectKey(objectKey, secret)
+	if !hmac.Equal([]byte(expected), []byte(strings.TrimSpace(token))) {
+		return "", false
+	}
+	return objectKey, true
+}
+
+func ObjectKeyFromToken(token string) (string, bool) {
+	parts := strings.Split(strings.TrimSpace(token), ".")
+	if len(parts) != 2 {
+		return "", false
+	}
+	objectKeyBytes, err := base64.RawURLEncoding.DecodeString(parts[0])
+	if err != nil {
+		return "", false
+	}
+	objectKey := strings.TrimSpace(string(objectKeyBytes))
+	if objectKey == "" {
+		return "", false
+	}
+	return objectKey, true
+}