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

backend/internal/service/openai_request_body_limit_failover_test.go

@@ -0,0 +1,135 @@
+package service
+
+import (
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/Wei-Shaw/sub2api/internal/config"
+	"github.com/gin-gonic/gin"
+	"github.com/stretchr/testify/require"
+	"github.com/tidwall/gjson"
+)
+
+func TestOpenAIRequestBodyLimitFailover_HTTP413SwitchesAccountsBeforeWrite(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	requestBody := []byte(`{"model":"gpt-5.2","stream":false,"input":"hello"}`)
+
+	for _, passthrough := range []bool{false, true} {
+		name := "native_responses"
+		if passthrough {
+			name = "api_key_passthrough"
+		}
+		t.Run(name, func(t *testing.T) {
+			rec := httptest.NewRecorder()
+			c, _ := gin.CreateTestContext(rec)
+			c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses", bytes.NewReader(nil))
+
+			const upstreamBody = `{"error":{"message":"request body exceeds this account's 16MB proxy limit; secret=must-not-leak","type":"invalid_request_error"}}`
+			body := &passthroughCloseTrackingReadCloser{Reader: strings.NewReader(upstreamBody)}
+			upstream := &httpUpstreamRecorder{resp: &http.Response{
+				StatusCode: http.StatusRequestEntityTooLarge,
+				Header: http.Header{
+					"Content-Type": []string{"application/json"},
+					"X-Request-Id": []string{"rid-body-limit"},
+				},
+				Body: body,
+			}}
+			svc := &OpenAIGatewayService{
+				cfg:          &config.Config{Gateway: config.GatewayConfig{ForceCodexCLI: false}},
+				httpUpstream: upstream,
+			}
+			account := &Account{
+				ID:          161,
+				Name:        name,
+				Platform:    PlatformOpenAI,
+				Type:        AccountTypeAPIKey,
+				Concurrency: 1,
+				Credentials: map[string]any{
+					"api_key":   "sk-test",
+					"base_url":  "https://api.example.test",
+					"pool_mode": true,
+					"pool_mode_retry_status_codes": []any{
+						float64(http.StatusRequestEntityTooLarge),
+					},
+				},
+				Extra: map[string]any{
+					"openai_passthrough":         passthrough,
+					"openai_responses_supported": true,
+				},
+				Status:      StatusActive,
+				Schedulable: true,
+			}
+
+			result, err := svc.Forward(context.Background(), c, account, requestBody)
+
+			require.Nil(t, result)
+			var failoverErr *UpstreamFailoverError
+			require.ErrorAs(t, err, &failoverErr)
+			require.Equal(t, http.StatusRequestEntityTooLarge, failoverErr.StatusCode)
+			require.Equal(t, GatewayFailureScopeAccount, failoverErr.Scope)
+			require.Equal(t, GatewayFailureReason("openai_request_body_too_large"), failoverErr.Reason)
+			require.Equal(t, NextAccountRetry, failoverErr.NextAccountAction)
+			require.Equal(t, http.StatusRequestEntityTooLarge, failoverErr.ClientStatusCode)
+			require.Equal(t, "Request payload is too large", failoverErr.ClientMessage)
+			require.False(t, failoverErr.RetryableOnSameAccount, "a body limit requires another account, not another attempt on the same account")
+			require.False(t, c.Writer.Written(), "account failover must happen before downstream output is committed")
+			require.Empty(t, rec.Body.String())
+			require.True(t, body.closed)
+			if passthrough {
+				require.Equal(t, requestBody, upstream.lastBody)
+			} else {
+				require.Equal(t, "gpt-5.2", gjson.GetBytes(upstream.lastBody, "model").String())
+				require.Equal(t, "hello", gjson.GetBytes(upstream.lastBody, "input").String())
+			}
+		})
+	}
+}
+
+func TestOpenAIRequestBodyLimitFailover_ContextWindow413DoesNotSwitchAccounts(t *testing.T) {
+	gin.SetMode(gin.TestMode)
+	requestBody := []byte(`{"model":"gpt-5.2","stream":false,"input":"hello"}`)
+
+	for _, passthrough := range []bool{false, true} {
+		t.Run(fmt.Sprintf("passthrough_%t", passthrough), func(t *testing.T) {
+			rec := httptest.NewRecorder()
+			c, _ := gin.CreateTestContext(rec)
+			c.Request = httptest.NewRequest(http.MethodPost, "/v1/responses", bytes.NewReader(nil))
+
+			const upstreamBody = `{"error":{"message":"Your input exceeds the context window of this model. Please adjust your input and try again.","type":"invalid_request_error"}}`
+			body := &passthroughCloseTrackingReadCloser{Reader: strings.NewReader(upstreamBody)}
+			svc := &OpenAIGatewayService{
+				cfg: &config.Config{Gateway: config.GatewayConfig{ForceCodexCLI: false}},
+				httpUpstream: &httpUpstreamRecorder{resp: &http.Response{
+					StatusCode: http.StatusRequestEntityTooLarge,
+					Header:     http.Header{"Content-Type": []string{"application/json"}},
+					Body:       body,
+				}},
+			}
+			account := &Account{
+				ID: 162, Platform: PlatformOpenAI, Type: AccountTypeAPIKey, Concurrency: 1,
+				Credentials: map[string]any{"api_key": "sk-test", "base_url": "https://api.example.test"},
+				Extra: map[string]any{
+					"openai_passthrough":         passthrough,
+					"openai_responses_supported": true,
+				},
+				Status: StatusActive, Schedulable: true,
+			}
+
+			result, err := svc.Forward(context.Background(), c, account, requestBody)
+
+			require.Nil(t, result)
+			require.Error(t, err)
+			var failoverErr *UpstreamFailoverError
+			require.False(t, errors.As(err, &failoverErr), "context-window failures are deterministic request errors")
+			require.True(t, c.Writer.Written())
+			require.Contains(t, rec.Body.String(), "exceeds the context window")
+			require.True(t, body.closed)
+		})
+	}
+}