feat(gateway): harden failover and payload handling

Retry pre-response transport failures across candidates with an explicit stop policy, and propagate end-to-end timing into usage records and UI diagnostics.

Remove legacy body, import, cookie, PII, and tunnel replay caps while preserving optional operator-configured gateway limits.

frontend/src/features/providers/components/FailoverRulesDialog.vue

@@ -8,6 +8,33 @@
     @update:model-value="handleClose"
   >
     <div class="space-y-5 max-h-[60vh] overflow-y-auto px-0.5 py-0.5 -mx-0.5">
+      <!-- 传输错误规则 -->
+      <div class="space-y-3">
+        <div>
+          <h3 class="text-sm font-medium">
+            传输错误
+          </h3>
+          <p class="text-xs text-muted-foreground mt-0.5">
+            这类错误没有可用于故障转移判断的上游 HTTP 状态码，因此不会命中下方的状态码规则
+          </p>
+        </div>
+
+        <div class="flex items-center justify-between gap-4 rounded-lg border bg-muted/50 p-3">
+          <div class="min-w-0 space-y-0.5">
+            <span class="text-sm font-medium">继续尝试下一候选</span>
+            <p class="text-xs leading-relaxed text-muted-foreground">
+              适用于 DNS 解析、TCP 连接、TLS 握手、代理/WARP 连接，以及响应提交前的连接重置或超时。默认开启；关闭后会立即返回网关错误。响应开始发送后无法切换候选。
+            </p>
+          </div>
+          <Switch
+            aria-label="传输错误时继续尝试下一候选"
+            class="shrink-0"
+            :model-value="continueOnTransportErrors"
+            @update:model-value="(value: boolean) => continueOnTransportErrors = value"
+          />
+        </div>
+      </div>
+
       <!-- 成功转移规则 -->
       <div class="space-y-3">
         <div class="flex items-start justify-between gap-3">
@@ -243,6 +270,7 @@ import {
   Dialog,
   Button,
   Input,
+  Switch,
   Textarea,
 } from '@/components/ui'
 import { AlignLeft, Code2, GitBranch, Plus, Trash2 } from 'lucide-vue-next'
@@ -263,6 +291,7 @@ const emit = defineEmits<{
 
 const { success, error: showError } = useToast()
 const saving = ref(false)
+const continueOnTransportErrors = ref(true)
 
 const successPatterns = ref<FailoverRuleItem[]>([])
 const errorPatterns = ref<FailoverRuleItem[]>([])
@@ -284,6 +313,7 @@ const TOP_LEVEL_STOP_STATUS_CODE_KEYS = [
 ] as const
 
 const MANAGED_FAILOVER_RULE_KEYS = [
+  'stop_on_transport_errors',
   'success_failover_patterns',
   'error_stop_patterns',
   ...TOP_LEVEL_STOP_STATUS_CODE_KEYS,
@@ -334,6 +364,9 @@ function buildNextFailoverRules(
   if (filteredError.length > 0) {
     nextRules.error_stop_patterns = filteredError
   }
+  if (!continueOnTransportErrors.value) {
+    nextRules.stop_on_transport_errors = true
+  }
 
   return Object.values(nextRules).some(hasPersistableFailoverValue)
     ? nextRules as FailoverRulesConfig
@@ -343,6 +376,7 @@ function buildNextFailoverRules(
 watch(() => [props.open, props.provider], () => {
   if (props.open && props.provider) {
     const rules = props.provider.failover_rules
+    continueOnTransportErrors.value = rules?.stop_on_transport_errors !== true
     successPatterns.value = (rules?.success_failover_patterns || []).map(r => ({
       ...r,
       pattern: r.pattern || '',

frontend/src/features/providers/components/ProviderDetailDrawer.vue

@@ -1188,6 +1188,7 @@ const hasFailoverRules = computed(() => {
   if (!rules) return false
   return FAILOVER_RULE_ARRAY_KEYS.some(key => (rules[key]?.length || 0) > 0)
     || typeof rules.max_retries === 'number'
+    || rules.stop_on_transport_errors === true
 })
 
 // Provider 级别代理配置状态

frontend/src/features/providers/components/ProviderFormDialog.vue

@@ -216,10 +216,11 @@
             </Label>
             <Input
               id="max-transfer-count"
-              :model-value="form.max_transfer_count"
+              :model-value="form.max_transfer_count === 0 ? '' : form.max_transfer_count"
               type="number"
               min="0"
               step="1"
+              :placeholder="legacyT('0 (不限制)')"
               @update:model-value="(v) => form.max_transfer_count = parseNumberInput(v, { min: 0 }) ?? 0"
             />
           </div>
@@ -233,10 +234,11 @@
             </Label>
             <Input
               id="max-transfer-timeout-seconds"
-              :model-value="form.max_transfer_timeout_seconds"
+              :model-value="form.max_transfer_timeout_seconds === 0 ? '' : form.max_transfer_timeout_seconds"
               type="number"
               min="0"
               step="1"
+              :placeholder="legacyT('0 (不限制)')"
               @update:model-value="(v) => form.max_transfer_timeout_seconds = parseNumberInput(v, { min: 0 }) ?? 0"
             />
           </div>

frontend/src/features/providers/components/__tests__/FailoverRulesDialog.transport-errors.spec.ts

@@ -0,0 +1,130 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest'
+import { createApp, nextTick, type App } from 'vue'
+
+import type { FailoverRulesConfig, ProviderWithEndpointsSummary } from '@/api/endpoints/types'
+import FailoverRulesDialog from '../FailoverRulesDialog.vue'
+
+const endpointMocks = vi.hoisted(() => ({
+  updateProvider: vi.fn(),
+}))
+
+vi.mock('@/api/endpoints', () => ({
+  updateProvider: endpointMocks.updateProvider,
+}))
+
+vi.mock('@/composables/useToast', () => ({
+  useToast: () => ({
+    success: vi.fn(),
+    error: vi.fn(),
+  }),
+}))
+
+const mountedApps: Array<{ app: App, root: HTMLElement }> = []
+
+function makeProvider(failoverRules: FailoverRulesConfig | null): ProviderWithEndpointsSummary {
+  return {
+    id: 'provider-1',
+    failover_rules: failoverRules,
+  } as ProviderWithEndpointsSummary
+}
+
+function mountDialog(failoverRules: FailoverRulesConfig | null = null) {
+  const root = document.createElement('div')
+  document.body.appendChild(root)
+  const app = createApp(FailoverRulesDialog, {
+    open: true,
+    provider: makeProvider(failoverRules),
+    'onUpdate:open': vi.fn(),
+  })
+  app.mount(root)
+  mountedApps.push({ app, root })
+}
+
+async function settle() {
+  for (let index = 0; index < 4; index += 1) {
+    await Promise.resolve()
+    await nextTick()
+  }
+}
+
+function transportErrorSwitch(): HTMLButtonElement {
+  const control = document.body.querySelector<HTMLButtonElement>(
+    '[role="switch"][aria-label="传输错误时继续尝试下一候选"]',
+  )
+  if (!control) throw new Error('Missing transport-error failover switch')
+  return control
+}
+
+function clickSave() {
+  const button = [...document.body.querySelectorAll<HTMLButtonElement>('button')]
+    .find(candidate => candidate.textContent?.trim() === '保存')
+  if (!button) throw new Error('Missing save button')
+  button.click()
+}
+
+beforeEach(() => {
+  endpointMocks.updateProvider.mockReset()
+  endpointMocks.updateProvider.mockResolvedValue(makeProvider(null))
+})
+
+afterEach(() => {
+  for (const { app, root } of mountedApps.splice(0)) {
+    app.unmount()
+    root.remove()
+  }
+  document.body.innerHTML = ''
+})
+
+describe('FailoverRulesDialog transport errors', () => {
+  it('continues failover by default and explains why HTTP status rules do not apply', async () => {
+    mountDialog()
+    await settle()
+
+    expect(transportErrorSwitch().getAttribute('aria-checked')).toBe('true')
+    expect(document.body.textContent).toContain('没有可用于故障转移判断的上游 HTTP 状态码')
+    expect(document.body.textContent).toContain('DNS 解析')
+    expect(document.body.textContent).toContain('TCP 连接')
+    expect(document.body.textContent).toContain('TLS 握手')
+    expect(document.body.textContent).toContain('响应提交前的连接重置或超时')
+    expect(document.body.textContent).toContain('响应开始发送后无法切换候选')
+  })
+
+  it('persists stop_on_transport_errors when continuing is disabled', async () => {
+    mountDialog()
+    await settle()
+
+    transportErrorSwitch().click()
+    await nextTick()
+    expect(transportErrorSwitch().getAttribute('aria-checked')).toBe('false')
+
+    clickSave()
+    await settle()
+
+    expect(endpointMocks.updateProvider).toHaveBeenCalledWith('provider-1', {
+      failover_rules: {
+        stop_on_transport_errors: true,
+      },
+    })
+  })
+
+  it('loads a stop rule and removes only that rule when continuing is enabled', async () => {
+    mountDialog({
+      max_retries: 2,
+      stop_on_transport_errors: true,
+    })
+    await settle()
+
+    expect(transportErrorSwitch().getAttribute('aria-checked')).toBe('false')
+    transportErrorSwitch().click()
+    await nextTick()
+
+    clickSave()
+    await settle()
+
+    expect(endpointMocks.updateProvider).toHaveBeenCalledWith('provider-1', {
+      failover_rules: {
+        max_retries: 2,
+      },
+    })
+  })
+})

frontend/src/features/providers/components/__tests__/ProviderDetailDrawer.loading.spec.ts

@@ -54,4 +54,8 @@ describe('ProviderDetailDrawer loading priorities', () => {
     expect(source).toContain('v-if="open && batchAssignDialogOpen && provider"')
     expect(source).toContain('v-if="open && failoverRulesDialogOpen"')
   })
+
+  it('marks a transport-error stop policy as a configured failover rule', () => {
+    expect(source).toContain('rules.stop_on_transport_errors === true')
+  })
 })

frontend/src/features/providers/components/__tests__/ProviderFormDialog.transfer-limits.spec.ts

@@ -177,15 +177,20 @@ describe('ProviderFormDialog transfer limits', () => {
     )
   })
 
-  it('defaults missing legacy values to explicit zero', async () => {
+  it('shows zero limits as unlimited placeholders while submitting explicit zero', async () => {
     mountDialog(makeProvider({
       max_transfer_count: undefined,
       max_transfer_timeout_seconds: undefined,
     }))
     await settle()
 
-    expect(document.body.querySelector<HTMLInputElement>('#max-transfer-count')?.value).toBe('0')
-    expect(document.body.querySelector<HTMLInputElement>('#max-transfer-timeout-seconds')?.value).toBe('0')
+    const countInput = document.body.querySelector<HTMLInputElement>('#max-transfer-count')
+    const timeoutInput = document.body.querySelector<HTMLInputElement>('#max-transfer-timeout-seconds')
+
+    expect(countInput?.value).toBe('')
+    expect(countInput?.placeholder).toBe('0 (不限制)')
+    expect(timeoutInput?.value).toBe('')
+    expect(timeoutInput?.placeholder).toBe('0 (不限制)')
 
     clickButton('保存')
     await settle()