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

backend/internal/handler/openai_gateway_reasoning_failover.go

@@ -0,0 +1,62 @@
+package handler
+
+import (
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"go.uber.org/zap"
+)
+
+// openAIPassthroughFailoverState tracks whether this forwarding loop has attempted
+// an OpenAI passthrough account. Once it has, every subsequent non-passthrough
+// attempt must use a sanitized body because the immutable canonical body can carry
+// provider-specific encrypted reasoning produced by that passthrough upstream.
+type openAIPassthroughFailoverState struct {
+	passthroughSeen bool
+}
+
+// deriveOpenAIForwardAttemptBody returns the request body for the upcoming forward
+// attempt against account. It always derives from the immutable canonical body and
+// only removes encrypted reasoning input item(s) when the loop has already attempted
+// a passthrough account and the upcoming account is non-passthrough. This remains
+// sticky across retries and additional non-passthrough accounts. Attempts before
+// any passthrough account, and all passthrough attempts, forward the canonical body
+// unchanged. The canonical slice is never mutated.
+//
+// This method is invoked exactly once per forward attempt, immediately before the
+// Forward call, and advances the failover state as a side effect.
+func (h *OpenAIGatewayHandler) deriveOpenAIForwardAttemptBody(
+	reqLog *zap.Logger,
+	canonicalBody []byte,
+	account *service.Account,
+	state *openAIPassthroughFailoverState,
+) []byte {
+	currentPassthrough := account.IsOpenAIPassthroughEnabled()
+	if currentPassthrough {
+		state.passthroughSeen = true
+		return canonicalBody
+	}
+	if !state.passthroughSeen {
+		return canonicalBody
+	}
+
+	sanitized, changed, err := service.SanitizeOpenAICrossModeFailoverReasoning(canonicalBody)
+	if err != nil {
+		if reqLog != nil {
+			reqLog.Warn("openai.failover_cross_mode_reasoning_sanitize_failed",
+				zap.Int64("account_id", account.ID),
+				zap.Error(err),
+			)
+		}
+		return canonicalBody
+	}
+	if !changed {
+		return canonicalBody
+	}
+	if reqLog != nil {
+		reqLog.Info("openai.failover_cross_mode_reasoning_stripped",
+			zap.Int64("account_id", account.ID),
+			zap.Bool("account_passthrough", currentPassthrough),
+			zap.Bool("passthrough_seen", true),
+		)
+	}
+	return sanitized
+}