Merge pull request #393 from IanShaw027/fix/gemini-thought-signature-preserve

fix(gemini): 修复 thoughtSignature 跨账号验证错误

backend/internal/service/gateway_service.go

@@ -305,6 +305,19 @@ func (s *GatewayService) BindStickySession(ctx context.Context, groupID *int64,
 	return s.cache.SetSessionAccountID(ctx, derefGroupID(groupID), sessionHash, accountID, stickySessionTTL)
 }
 
+// GetCachedSessionAccountID retrieves the account ID bound to a sticky session.
+// Returns 0 if no binding exists or on error.
+func (s *GatewayService) GetCachedSessionAccountID(ctx context.Context, groupID *int64, sessionHash string) (int64, error) {
+	if sessionHash == "" || s.cache == nil {
+		return 0, nil
+	}
+	accountID, err := s.cache.GetSessionAccountID(ctx, derefGroupID(groupID), sessionHash)
+	if err != nil {
+		return 0, err
+	}
+	return accountID, nil
+}
+
 func (s *GatewayService) extractCacheableContent(parsed *ParsedRequest) string {
 	if parsed == nil {
 		return ""

backend/internal/service/gemini_native_signature_cleaner.go

@@ -0,0 +1,72 @@
+package service
+
+import (
+	"encoding/json"
+)
+
+// CleanGeminiNativeThoughtSignatures 从 Gemini 原生 API 请求中移除 thoughtSignature 字段，
+// 以避免跨账号签名验证错误。
+//
+// 当粘性会话切换账号时（例如原账号异常、不可调度等），旧账号返回的 thoughtSignature
+// 会导致新账号的签名验证失败。通过移除这些签名，让新账号重新生成有效的签名。
+//
+// CleanGeminiNativeThoughtSignatures removes thoughtSignature fields from Gemini native API requests
+// to avoid cross-account signature validation errors.
+//
+// When sticky session switches accounts (e.g., original account becomes unavailable),
+// thoughtSignatures from the old account will cause validation failures on the new account.
+// By removing these signatures, we allow the new account to generate valid signatures.
+func CleanGeminiNativeThoughtSignatures(body []byte) []byte {
+	if len(body) == 0 {
+		return body
+	}
+
+	// 解析 JSON
+	var data any
+	if err := json.Unmarshal(body, &data); err != nil {
+		// 如果解析失败，返回原始 body（可能不是 JSON 或格式不正确）
+		return body
+	}
+
+	// 递归清理 thoughtSignature
+	cleaned := cleanThoughtSignaturesRecursive(data)
+
+	// 重新序列化
+	result, err := json.Marshal(cleaned)
+	if err != nil {
+		// 如果序列化失败，返回原始 body
+		return body
+	}
+
+	return result
+}
+
+// cleanThoughtSignaturesRecursive 递归遍历数据结构，移除所有 thoughtSignature 字段
+func cleanThoughtSignaturesRecursive(data any) any {
+	switch v := data.(type) {
+	case map[string]any:
+		// 创建新的 map，移除 thoughtSignature
+		result := make(map[string]any, len(v))
+		for key, value := range v {
+			// 跳过 thoughtSignature 字段
+			if key == "thoughtSignature" {
+				continue
+			}
+			// 递归处理嵌套结构
+			result[key] = cleanThoughtSignaturesRecursive(value)
+		}
+		return result
+
+	case []any:
+		// 递归处理数组中的每个元素
+		result := make([]any, len(v))
+		for i, item := range v {
+			result[i] = cleanThoughtSignaturesRecursive(item)
+		}
+		return result
+
+	default:
+		// 基本类型（string, number, bool, null）直接返回
+		return v
+	}
+}