Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

backend/internal/service/openai_gateway_usage_integrity.go

@@ -0,0 +1,81 @@
+package service
+
+import (
+	"encoding/json"
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+)
+
+const (
+	grokMissingUsageErrorCode = "grok_missing_usage"
+	grokMissingUsageMessage   = "xAI upstream returned a successful chat completion without billable usage"
+)
+
+// hasBillableGrokChatUsage stays aligned with the aggregate token buckets used
+// to account for chat completions. Detail fields alone do not prove that the
+// successful response can be settled safely.
+func hasBillableGrokChatUsage(usage OpenAIUsage) bool {
+	return usage.InputTokens > 0 ||
+		usage.OutputTokens > 0 ||
+		usage.CacheCreationInputTokens > 0 ||
+		usage.CacheReadInputTokens > 0
+}
+
+// requiresBillableGrokChatUsage identifies Grok traffic by both account
+// platform and model identity. Grok models may be served through generic
+// OpenAI-compatible accounts, so account.Platform alone is not a safe billing
+// boundary.
+func requiresBillableGrokChatUsage(account *Account, models ...string) bool {
+	if account != nil && account.Platform == PlatformGrok {
+		return true
+	}
+	for _, model := range models {
+		normalized := strings.ToLower(strings.TrimSpace(model))
+		if separator := strings.LastIndex(normalized, "/"); separator >= 0 {
+			normalized = strings.TrimSpace(normalized[separator+1:])
+		}
+		if normalized == "grok" || strings.HasPrefix(normalized, "grok-") {
+			return true
+		}
+	}
+	return false
+}
+
+func newGrokMissingUsageFailoverError(c *gin.Context, account *Account, upstreamRequestID string) *UpstreamFailoverError {
+	accountID := int64(0)
+	accountName := ""
+	if account != nil {
+		accountID = account.ID
+		accountName = account.Name
+	}
+
+	setOpsUpstreamError(c, http.StatusBadGateway, grokMissingUsageMessage, "")
+	appendOpsUpstreamError(c, OpsUpstreamErrorEvent{
+		Platform:           PlatformGrok,
+		AccountID:          accountID,
+		AccountName:        accountName,
+		UpstreamStatusCode: http.StatusBadGateway,
+		UpstreamRequestID:  strings.TrimSpace(upstreamRequestID),
+		Kind:               "failover",
+		Message:            grokMissingUsageMessage,
+	})
+
+	body, _ := json.Marshal(gin.H{
+		"error": gin.H{
+			"type":    "upstream_error",
+			"code":    grokMissingUsageErrorCode,
+			"message": grokMissingUsageMessage,
+		},
+	})
+	headers := http.Header{}
+	if requestID := strings.TrimSpace(upstreamRequestID); requestID != "" {
+		headers.Set("x-request-id", requestID)
+	}
+	return &UpstreamFailoverError{
+		StatusCode:      http.StatusBadGateway,
+		ResponseBody:    body,
+		ResponseHeaders: headers,
+	}
+}