Merge pull request #6129 from alfadb/feature/openai-fast-service-tier

feat(openai): Fast 档位请求校验、响应透传与按上游实际档位计费

backend/internal/handler/openai_chat_completions.go

@@ -89,6 +89,10 @@ func (h *OpenAIGatewayHandler) ChatCompletions(c *gin.Context) {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", invalidStreamFieldTypeMessage)
 		return
 	}
+	if _, err := service.ValidateOpenAIServiceTierField(body); err != nil {
+		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", err.Error())
+		return
+	}
 	if service.IsGPTImageGenerationModel(reqModel) {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", "This model is not supported on the Chat Completions endpoint")
 		return

backend/internal/handler/openai_gateway_handler.go

@@ -392,6 +392,10 @@ func (h *OpenAIGatewayHandler) Responses(c *gin.Context) {
 		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", invalidStreamFieldTypeMessage)
 		return
 	}
+	if _, err := service.ValidateOpenAIServiceTierField(body); err != nil {
+		h.errorResponse(c, http.StatusBadRequest, "invalid_request_error", err.Error())
+		return
+	}
 	reqLog = reqLog.With(zap.String("model", reqModel), zap.Bool("stream", reqStream))
 	previousResponseID := strings.TrimSpace(gjson.GetBytes(body, "previous_response_id").String())
 	if previousResponseID != "" {

backend/internal/handler/openai_service_tier_validation_test.go

@@ -0,0 +1,94 @@
+package handler
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	middleware2 "github.com/Wei-Shaw/sub2api/internal/server/middleware"
+	"github.com/Wei-Shaw/sub2api/internal/service"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+)
+
+// 非法 service_tier 必须在两个 OpenAI 端点（/v1/responses、/v1/chat/completions）
+// 上以 OpenAI 兼容错误结构返回 HTTP 400。这些用例在 handler 的 service_tier
+// 校验处短路，不会进入账号选择/重试。
+//
+// 合法值（fast/priority/flex/auto/default/scale）与省略/null 的接受语义由
+// service 层纯校验函数 TestValidateOpenAIServiceTierField 覆盖，避免 handler
+// 测试走入真实账号选择/重试路径。
+
+func newServiceTierHandlerTest(t *testing.T) *OpenAIGatewayHandler {
+	t.Helper()
+	return &OpenAIGatewayHandler{
+		gatewayService:      &service.OpenAIGatewayService{},
+		billingCacheService: service.NewBillingCacheService(nil, nil, nil, nil, nil, nil, &config.Config{RunMode: config.RunModeSimple}, nil),
+		apiKeyService:       &service.APIKeyService{},
+		concurrencyHelper: &ConcurrencyHelper{concurrencyService: service.NewConcurrencyService(
+			&helperConcurrencyCacheStub{userSeq: []bool{true}},
+		)},
+		cfg:          &config.Config{},
+		imageLimiter: &imageConcurrencyLimiter{},
+	}
+}
+
+func runOpenAIHandlerServiceTierTest(t *testing.T, path, body string, handler func(h *OpenAIGatewayHandler, c *gin.Context)) *httptest.ResponseRecorder {
+	t.Helper()
+	gin.SetMode(gin.TestMode)
+	rec := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(rec)
+	c.Request = httptest.NewRequest(http.MethodPost, path, strings.NewReader(body))
+	c.Request.Header.Set("Content-Type", "application/json")
+
+	groupID := int64(6401)
+	userID := int64(6402)
+	c.Set(string(middleware2.ContextKeyAPIKey), &service.APIKey{
+		ID:      6403,
+		GroupID: &groupID,
+		Group: &service.Group{
+			ID:       groupID,
+			Platform: service.PlatformOpenAI,
+		},
+		User: &service.User{ID: userID, Status: service.StatusActive},
+	})
+	c.Set(string(middleware2.ContextKeyUser), middleware2.AuthSubject{UserID: userID, Concurrency: 1})
+
+	handler(newServiceTierHandlerTest(t), c)
+	return rec
+}
+
+func TestOpenAIGatewayHandlerResponses_InvalidServiceTierRejected400(t *testing.T) {
+	for _, body := range []string{
+		`{"model":"gpt-5.5","input":"hi","service_tier":"turbo"}`,
+		`{"model":"gpt-5.5","input":"hi","service_tier":"SPEED"}`,
+		`{"model":"gpt-5.5","input":"hi","service_tier":""}`,
+		`{"model":"gpt-5.5","input":"hi","service_tier":123}`,
+		`{"model":"gpt-5.5","input":"hi","service_tier":{}}`,
+	} {
+		rec := runOpenAIHandlerServiceTierTest(t, "/v1/responses", body, func(h *OpenAIGatewayHandler, c *gin.Context) {
+			h.Responses(c)
+		})
+		require.Equal(t, http.StatusBadRequest, rec.Code, "body=%s", body)
+		require.Contains(t, rec.Body.String(), "invalid_request_error", "body=%s", body)
+		require.Contains(t, rec.Body.String(), "invalid service_tier", "body=%s", body)
+	}
+}
+
+func TestOpenAIGatewayHandlerChatCompletions_InvalidServiceTierRejected400(t *testing.T) {
+	for _, body := range []string{
+		`{"model":"gpt-5.5","messages":[{"role":"user","content":"hi"}],"service_tier":"turbo"}`,
+		`{"model":"gpt-5.5","messages":[{"role":"user","content":"hi"}],"service_tier":"ultra"}`,
+		`{"model":"gpt-5.5","messages":[{"role":"user","content":"hi"}],"service_tier":""}`,
+		`{"model":"gpt-5.5","messages":[{"role":"user","content":"hi"}],"service_tier":["priority"]}`,
+	} {
+		rec := runOpenAIHandlerServiceTierTest(t, "/v1/chat/completions", body, func(h *OpenAIGatewayHandler, c *gin.Context) {
+			h.ChatCompletions(c)
+		})
+		require.Equal(t, http.StatusBadRequest, rec.Code, "body=%s", body)
+		require.Contains(t, rec.Body.String(), "invalid_request_error", "body=%s", body)
+		require.Contains(t, rec.Body.String(), "invalid service_tier", "body=%s", body)
+	}
+}