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

backend/internal/service/openai_compaction_context.go

@@ -0,0 +1,32 @@
+package service
+
+import "context"
+
+type openAIForwardModelContextKey struct{}
+
+type openAIForwardModel struct {
+	model                  string
+	useCompactModelMapping bool
+}
+
+// WithOpenAIForwardModel records the model present in the forwarded request
+// body after channel mapping and whether the legacy /responses/compact-only
+// model mapping applies. Native remote compaction v2 keeps this false, so
+// channel restriction checks follow the same model chain used by Forward.
+func WithOpenAIForwardModel(ctx context.Context, forwardModel string, useCompactModelMapping bool) context.Context {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+	return context.WithValue(ctx, openAIForwardModelContextKey{}, openAIForwardModel{
+		model:                  forwardModel,
+		useCompactModelMapping: useCompactModelMapping,
+	})
+}
+
+func openAIForwardModelFromContext(ctx context.Context) (openAIForwardModel, bool) {
+	if ctx == nil {
+		return openAIForwardModel{}, false
+	}
+	forwardModel, ok := ctx.Value(openAIForwardModelContextKey{}).(openAIForwardModel)
+	return forwardModel, ok
+}