feat(site): 站点拨测支持接口返回内容监控（文本 + JSON 字段）

需求：监控接口返回的数据本身是否变化（如 Cloudflare ips-v4 的 IP 段清单），
而不是只看服务是否可用。两者是不同的问题：服务 200 OK 但内容变了，拨测发现不了。

后端
- SiteTask 新增 content_check_mode(off/text/json)、content_paths(JSONPath)、
  content_ignore_rules、content_min_length、content_confirm_times、content_sort_lines
- 新增 monitor_site_baselines（基线多版本）与 monitor_site_content_changes（变更记录）
- pkg/siteprobe/content.go：零依赖 JSONPath（$.a.b[0]、$.a[*].b）、文本/JSON 规范化、
  sha256 哈希、LCS 行级 diff、字段级 diff
- 核心判定区分「采集异常」与「内容变更」：状态码非 2xx、空响应、短于最小长度、
  非合法 JSON 均不算变更，避免 CDN 拦截页造成误报
- 连续 N 次（默认 2）不一致才落变更记录，抑制抖动
- 基线首次自动建立（用户选择自动接受），之后变更需人工「接受为新基线」并留审计
- 补齐历史遗留死字段：expected_content（正则断言）与 expected_length 此前
  只有表结构、执行器从未校验，现已实现
- 告警引擎新增 content_changed 指标，人工处理后自动恢复
- 迁移 0006 用 AutoMigrate 实现幂等（空库 0000 已建表，静态 ALTER 会重复列）

前端
- 任务表单新增内容监控配置区（模式/JSONPath/忽略规则/最小长度/确认次数/排序）
- 详情页新增内容监控面板：当前基线、待确认变更、并排 diff、版本历史、
  接受/忽略操作

验证
- 9 项单元测试（JSONPath、时间戳忽略、顺序无关、采集异常、字段级监控、diff）
- 端到端：Cloudflare ips-v4 建基线 v1 → 模拟变更 → 第 2 轮告警 → 接受为 v2
- JSON 模式实测快照仅含指定字段：{"$.db_driver":"mysql","$.version":"v1.0.2"}

// Logan.Li

frontend/src/api/monitor/site.ts

@@ -2,6 +2,16 @@
 
 import { http } from '@/utils/request';
 
+// 内容监控配置（随任务一起提交） // Logan.Li
+export interface ContentCheckPayload {
+  content_check_mode?: 'off' | 'text' | 'json';
+  content_paths?: string;
+  content_ignore_rules?: string;
+  content_min_length?: number;
+  content_confirm_times?: number;
+  content_sort_lines?: boolean;
+}
+
 export const siteApi = {
   getStats: async () => http.get('/site/stats'),
   getTasks: async () => http.get<{ list: unknown[]; total: number }>('/site/tasks'),
@@ -9,12 +19,12 @@ export const siteApi = {
     name: string; url: string; type: string;
     frequency_sec?: number; timeout_sec?: number; expected_status_code?: number;
     enabled?: boolean;
-  }) => http.post('/site/tasks', data),
+  } & ContentCheckPayload) => http.post('/site/tasks', data),
   updateTask: async (id: number | string, data: {
     name?: string; url?: string; type?: string;
     frequency_sec?: number; timeout_sec?: number; expected_status_code?: number;
     enabled?: boolean;
-  }) => http.put(`/site/tasks/${id}`, data),
+  } & ContentCheckPayload) => http.put(`/site/tasks/${id}`, data),
   deleteTask: async (id: number | string) => http.delete(`/site/tasks/${id}`),
   toggleTask: async (id: number | string, enabled: boolean) =>
     http.put(`/site/tasks/${id}`, { enabled }),
@@ -27,4 +37,19 @@ export const siteApi = {
     limit: opts?.limit ?? 500,
     ...(opts?.hours ? { hours: opts.hours } : {}),
   }),
-};
+
+  // ── 内容监控 ──────────────────────────────────────────────
+  /** 当前基线 + 待确认变更 + 配置，一次拿全供详情页渲染 */
+  getTaskContent: async (id: number | string) => http.get(`/site/tasks/${id}/content`),
+  /** 基线版本历史 */
+  getBaselines: async (id: number | string) => http.get(`/site/tasks/${id}/baselines`),
+  /** 变更记录，可按 status 过滤 */
+  getContentChanges: async (id: number | string, status?: string) =>
+    http.get(`/site/tasks/${id}/changes`, status ? { status } : undefined),
+  /** 接受为新基线（人工确认） */
+  acceptChange: async (changeId: number | string, note?: string) =>
+    http.post(`/site/changes/${changeId}/accept`, { note: note ?? '' }),
+  /** 标记为误报忽略 */
+  ignoreChange: async (changeId: number | string) =>
+    http.post(`/site/changes/${changeId}/ignore`),
+};

frontend/src/pages/monitor/SiteMonitor.tsx

@@ -33,11 +33,24 @@ import {
 interface CreateTaskForm {
   name: string; url: string; type: ProbeType;
   frequency_sec: number; timeout_sec: number; expected_status_code: number;
+  // 内容监控 // Logan.Li
+  content_check_mode: 'off' | 'text' | 'json';
+  content_paths: string;
+  content_ignore_rules: string;
+  content_min_length: number;
+  content_confirm_times: number;
+  content_sort_lines: boolean;
 }
 
 const emptyForm: CreateTaskForm = {
   name: '', url: '', type: 'HTTP',
   frequency_sec: defaultProbeFrequency('HTTP'), timeout_sec: 10, expected_status_code: 200,
+  content_check_mode: 'off',
+  content_paths: '',
+  content_ignore_rules: '',
+  content_min_length: 0,
+  content_confirm_times: 2,
+  content_sort_lines: false,
 };
 
 const FILTER_TYPES: Array<ProbeType | 'ALL'> = ['ALL', ...PROBE_TYPE_OPTIONS];
@@ -124,6 +137,13 @@ export function SiteMonitor() {
       frequency_sec: task.frequency_sec || 60,
       timeout_sec: task.timeout_sec || 10,
       expected_status_code: task.expected_status_code || 200,
+      // 回填内容监控配置，否则编辑保存会把已配好的规则清空 // Logan.Li
+      content_check_mode: (task.content_check_mode as CreateTaskForm['content_check_mode']) || 'off',
+      content_paths: task.content_paths || '',
+      content_ignore_rules: task.content_ignore_rules || '',
+      content_min_length: task.content_min_length || 0,
+      content_confirm_times: task.content_confirm_times || 2,
+      content_sort_lines: Boolean(task.content_sort_lines),
     });
     setFormOpen(true);
   };
@@ -144,6 +164,13 @@ export function SiteMonitor() {
       frequency_sec: Number(form.frequency_sec) || 60,
       timeout_sec: Number(form.timeout_sec) || 10,
       expected_status_code: Number(form.expected_status_code) || 200,
+      // 内容监控：off 时后端会忽略其余字段并清空基线 // Logan.Li
+      content_check_mode: form.content_check_mode,
+      content_paths: form.content_paths,
+      content_ignore_rules: form.content_ignore_rules,
+      content_min_length: Number(form.content_min_length) || 0,
+      content_confirm_times: Number(form.content_confirm_times) || 2,
+      content_sort_lines: form.content_sort_lines,
     };
     try {
       if (editingTaskId) { await siteApi.updateTask(editingTaskId, payload); toast.success(i18n.t('monitor.sitemonitortsx.se01498ee')); }
@@ -388,6 +415,76 @@ export function SiteMonitor() {
                   onChange={(e) => setForm({ ...form, expected_status_code: Number(e.target.value) || 200 })} />
               </div>
             )}
+            {form.type === 'HTTP' && (
+              <>
+                <div className="grid gap-1.5">
+                  <Label>内容变化监控</Label>
+                  <Select
+                    value={form.content_check_mode}
+                    onValueChange={(v) => setForm({ ...form, content_check_mode: v as CreateTaskForm['content_check_mode'] })}
+                  >
+                    <SelectTrigger><SelectValue /></SelectTrigger>
+                    <SelectContent>
+                      <SelectItem value="off">关闭（只检查可用性）</SelectItem>
+                      <SelectItem value="text">文本内容（如 IP 段清单）</SelectItem>
+                      <SelectItem value="json">JSON 字段（如 $.data.status）</SelectItem>
+                    </SelectContent>
+                  </Select>
+                  <p className="text-[10px] text-[var(--dg-text-muted)]">
+                    开启后，返回内容与基线不同时告警。只有拨测成功才参与比对，避免错误页被误报成"内容变更"。
+                  </p>
+                </div>
+
+                {form.content_check_mode === 'json' && (
+                  <div className="grid gap-1.5">
+                    <Label>监控字段（JSONPath，每行一个）</Label>
+                    <textarea
+                      className="w-full min-h-[64px] bg-[var(--dg-bg-secondary)] border border-[var(--dg-border)] rounded px-2 py-1.5 text-xs text-[var(--dg-text-primary)] font-mono"
+                      value={form.content_paths}
+                      onChange={(e) => setForm({ ...form, content_paths: e.target.value })}
+                      placeholder={'$.data.status\n$.data.ips[*].ip'}
+                    />
+                    <p className="text-[10px] text-[var(--dg-text-muted)]">只有列出的字段参与比对，其余字段变化不会告警。</p>
+                  </div>
+                )}
+
+                {form.content_check_mode !== 'off' && (
+                  <>
+                    <div className="grid gap-1.5">
+                      <Label>忽略规则（正则，每行一条）</Label>
+                      <textarea
+                        className="w-full min-h-[52px] bg-[var(--dg-bg-secondary)] border border-[var(--dg-border)] rounded px-2 py-1.5 text-xs text-[var(--dg-text-primary)] font-mono"
+                        value={form.content_ignore_rules}
+                        onChange={(e) => setForm({ ...form, content_ignore_rules: e.target.value })}
+                        placeholder={'"updated_at":\\s*"[^"]*"'}
+                      />
+                      <p className="text-[10px] text-[var(--dg-text-muted)]">用于剔除时间戳、nonce、trace_id 等每次都变的字段。</p>
+                    </div>
+                    <div className="grid grid-cols-2 gap-3">
+                      <div className="grid gap-1.5">
+                        <Label>最小有效长度</Label>
+                        <Input type="number" min={0} value={form.content_min_length}
+                          onChange={(e) => setForm({ ...form, content_min_length: Number(e.target.value) || 0 })} />
+                        <p className="text-[10px] text-[var(--dg-text-muted)]">低于此值判为采集异常。</p>
+                      </div>
+                      <div className="grid gap-1.5">
+                        <Label>连续确认次数</Label>
+                        <Input type="number" min={1} max={10} value={form.content_confirm_times}
+                          onChange={(e) => setForm({ ...form, content_confirm_times: Number(e.target.value) || 2 })} />
+                        <p className="text-[10px] text-[var(--dg-text-muted)]">连续 N 次不同才告警。</p>
+                      </div>
+                    </div>
+                    {form.content_check_mode === 'text' && (
+                      <div className="flex items-center gap-2">
+                        <Switch checked={form.content_sort_lines}
+                          onCheckedChange={(v) => setForm({ ...form, content_sort_lines: v })} />
+                        <Label>忽略行顺序（清单类接口建议开启）</Label>
+                      </div>
+                    )}
+                  </>
+                )}
+              </>
+            )}
           </div>
           <DialogFooter>
             <Button variant="outline" onClick={() => { setFormOpen(false); setEditingTaskId(null); }} disabled={saving}> {i18n.t('rbac.jobRole.cancel')} </Button>

frontend/src/pages/monitor/site-monitor/SiteContentPanel.tsx

@@ -0,0 +1,248 @@
+// 站点拨测 — 内容监控面板：当前基线 / 待确认变更 / 并排 diff / 版本历史。 // Logan.Li
+import { useCallback, useEffect, useState } from 'react';
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card';
+import { Button } from '@/components/ui/button';
+import { Badge } from '@/components/ui/badge';
+import {
+  Table, TableBody, TableCell, TableHead, TableHeader, TableRow,
+} from '@/components/ui/table';
+import { Loader2, GitCompare, Check, EyeOff, History, RefreshCw } from 'lucide-react';
+import { toast } from 'sonner';
+import { siteApi } from '@/api';
+import type { JsonData } from '@/types/common';
+
+interface TextDiffLine { type: 'same' | 'add' | 'del'; old?: string; new?: string }
+interface FieldDiff { path: string; old: string; new: string; kind: 'changed' | 'added' | 'removed' }
+
+interface Baseline {
+  id: number; version: number; content_hash: string;
+  source: string; accepted_by?: string; note?: string; created_at: string;
+}
+interface ContentChange {
+  id: number; from_version: number; diff_type: string;
+  diff_payload: string; status: string; detected_at: string;
+}
+
+interface ContentView {
+  enabled: boolean;
+  mode: string;
+  baseline?: Baseline;
+  pending?: ContentChange;
+  baseline_count: number;
+  pending_change_count: number;
+  has_baseline: boolean;
+  has_pending: boolean;
+}
+
+const fmtTime = (iso?: string) => {
+  if (!iso) return '--';
+  const d = new Date(iso);
+  const p = (n: number) => String(n).padStart(2, '0');
+  return `${d.getFullYear()}-${p(d.getMonth() + 1)}-${p(d.getDate())} ${p(d.getHours())}:${p(d.getMinutes())}`;
+};
+
+export function SiteContentPanel({ taskId }: { taskId: number }) {
+  const [data, setData] = useState<ContentView | null>(null);
+  const [baselines, setBaselines] = useState<Baseline[]>([]);
+  const [loading, setLoading] = useState(true);
+  const [acting, setActing] = useState(false);
+  const [showHistory, setShowHistory] = useState(false);
+
+  const load = useCallback(async () => {
+    try {
+      const view = (await siteApi.getTaskContent(taskId)) as ContentView;
+      setData(view);
+      if (view?.enabled) {
+        const list = (await siteApi.getBaselines(taskId)) as Baseline[];
+        setBaselines(Array.isArray(list) ? list : []);
+      }
+    } catch {
+      /* 面板为增强信息，失败时不打断详情页 */
+    } finally {
+      setLoading(false);
+    }
+  }, [taskId]);
+
+  useEffect(() => { load(); }, [load]);
+
+  const act = async (fn: () => Promise<unknown>, okMsg: string) => {
+    setActing(true);
+    try {
+      await fn();
+      toast.success(okMsg);
+      await load();
+    } catch (e) {
+      toast.error((e as JsonData)?.message as string || '操作失败');
+    } finally {
+      setActing(false);
+    }
+  };
+
+  if (loading) {
+    return (
+      <Card className="bg-[var(--dg-bg-secondary)] border-[var(--dg-border)]">
+        <CardContent className="py-6 text-center text-[var(--dg-text-muted)]">
+          <Loader2 className="h-4 w-4 animate-spin mx-auto" />
+        </CardContent>
+      </Card>
+    );
+  }
+
+  // 未启用内容监控时整块隐藏，避免干扰普通拨测任务的详情页。
+  if (!data?.enabled) return null;
+
+  const diffLines: TextDiffLine[] = (() => {
+    if (data.pending?.diff_type !== 'text_line' || !data.pending?.diff_payload) return [];
+    try { return JSON.parse(data.pending.diff_payload) as TextDiffLine[]; } catch { return []; }
+  })();
+  const fieldDiffs: FieldDiff[] = (() => {
+    if (data.pending?.diff_type !== 'json_field' || !data.pending?.diff_payload) return [];
+    try { return JSON.parse(data.pending.diff_payload) as FieldDiff[]; } catch { return []; }
+  })();
+
+  return (
+    <Card className="bg-[var(--dg-bg-secondary)] border-[var(--dg-border)]">
+      <CardHeader className="pb-3 flex flex-row items-center justify-between">
+        <CardTitle className="text-sm flex items-center gap-2">
+          <GitCompare className="h-4 w-4" />
+          内容监控
+          <Badge variant="outline" className="text-[10px]">{data.mode === 'json' ? 'JSON 字段' : '文本'}</Badge>
+        </CardTitle>
+        <div className="flex items-center gap-2">
+          <Button variant="ghost" size="sm" className="h-7" onClick={() => setShowHistory((v) => !v)}>
+            <History className="h-3.5 w-3.5 mr-1" />
+            基线 v{data.baseline?.version ?? '-'}（{data.baseline_count} 版）
+          </Button>
+          <Button variant="ghost" size="sm" className="h-7" onClick={load}>
+            <RefreshCw className="h-3.5 w-3.5" />
+          </Button>
+        </div>
+      </CardHeader>
+      <CardContent className="space-y-3">
+        {!data.has_baseline && (
+          <p className="text-xs text-[var(--dg-text-muted)]">
+            尚未采集到基线，下一轮拨测完成后会自动建立 v1。
+          </p>
+        )}
+
+        {data.has_baseline && !data.has_pending && (
+          <p className="text-xs text-[var(--dg-text-muted)]">
+            内容与基线一致（v{data.baseline?.version}，采集于 {fmtTime(data.baseline?.created_at)}）。
+          </p>
+        )}
+
+        {data.has_pending && data.pending && (
+          <>
+            <div className="flex items-center justify-between flex-wrap gap-2">
+              <div className="text-xs">
+                <span className="text-[var(--dg-text-primary)] font-medium">
+                  检测到内容变更
+                </span>
+                <span className="text-[var(--dg-text-muted)] ml-2">
+                  v{data.pending.from_version} → 当前 · {fmtTime(data.pending.detected_at)}
+                </span>
+              </div>
+              <div className="flex gap-2">
+                <Button size="sm" className="h-7" disabled={acting}
+                  onClick={() => act(() => siteApi.acceptChange(data.pending!.id), '已接受为新基线')}>
+                  <Check className="h-3.5 w-3.5 mr-1" />接受为新基线
+                </Button>
+                <Button size="sm" variant="outline" className="h-7" disabled={acting}
+                  onClick={() => act(() => siteApi.ignoreChange(data.pending!.id), '已忽略该变更')}>
+                  <EyeOff className="h-3.5 w-3.5 mr-1" />忽略
+                </Button>
+              </div>
+            </div>
+
+            {fieldDiffs.length > 0 && (
+              <div className="rounded border border-[var(--dg-border)] overflow-hidden">
+                <Table>
+                  <TableHeader>
+                    <TableRow>
+                      <TableHead className="h-8 text-xs">字段</TableHead>
+                      <TableHead className="h-8 text-xs">变更前</TableHead>
+                      <TableHead className="h-8 text-xs">变更后</TableHead>
+                    </TableRow>
+                  </TableHeader>
+                  <TableBody>
+                    {fieldDiffs.map((f, i) => (
+                      <TableRow key={i}>
+                        <TableCell className="py-1 text-xs font-mono">{f.path}</TableCell>
+                        <TableCell className="py-1 text-xs font-mono text-[var(--dg-text-muted)] break-all">
+                          {f.old || <span className="italic">（无）</span>}
+                        </TableCell>
+                        <TableCell className="py-1 text-xs font-mono dg-text-yellow break-all">
+                          {f.new || <span className="italic">（已删除）</span>}
+                        </TableCell>
+                      </TableRow>
+                    ))}
+                  </TableBody>
+                </Table>
+              </div>
+            )}
+
+            {diffLines.length > 0 && (
+              <div className="rounded border border-[var(--dg-border)] overflow-x-auto max-h-[380px] overflow-y-auto">
+                <table className="w-full text-xs font-mono">
+                  <tbody>
+                    {diffLines.map((d, i) => {
+                      const isAdd = d.type === 'add';
+                      const isDel = d.type === 'del';
+                      return (
+                        <tr key={i}
+                          className={isAdd ? 'bg-[var(--dg-green)]/10' : isDel ? 'bg-[var(--dg-red)]/10' : ''}>
+                          <td className="w-6 text-center select-none text-[var(--dg-text-muted)]">
+                            {isAdd ? '+' : isDel ? '−' : ''}
+                          </td>
+                          <td className={`px-2 py-0.5 whitespace-pre-wrap break-all ${isDel ? 'dg-text-red line-through' : ''}`}>
+                            {isDel ? d.old : d.new}
+                          </td>
+                        </tr>
+                      );
+                    })}
+                  </tbody>
+                </table>
+              </div>
+            )}
+          </>
+        )}
+
+        {showHistory && (
+          <div className="rounded border border-[var(--dg-border)] overflow-hidden">
+            <Table>
+              <TableHeader>
+                <TableRow>
+                  <TableHead className="h-8 text-xs">版本</TableHead>
+                  <TableHead className="h-8 text-xs">来源</TableHead>
+                  <TableHead className="h-8 text-xs">确认人</TableHead>
+                  <TableHead className="h-8 text-xs">时间</TableHead>
+                  <TableHead className="h-8 text-xs">备注</TableHead>
+                </TableRow>
+              </TableHeader>
+              <TableBody>
+                {baselines.length === 0 ? (
+                  <TableRow>
+                    <TableCell colSpan={5} className="py-3 text-center text-xs text-[var(--dg-text-muted)]">暂无基线</TableCell>
+                  </TableRow>
+                ) : baselines.map((b) => (
+                  <TableRow key={b.id}>
+                    <TableCell className="py-1 text-xs">
+                      v{b.version}
+                      {b.id === data.baseline?.id && (
+                        <Badge variant="outline" className="ml-1 text-[9px]">当前</Badge>
+                      )}
+                    </TableCell>
+                    <TableCell className="py-1 text-xs">{b.source === 'manual' ? '人工接受' : '自动建立'}</TableCell>
+                    <TableCell className="py-1 text-xs">{b.accepted_by || '-'}</TableCell>
+                    <TableCell className="py-1 text-xs">{fmtTime(b.created_at)}</TableCell>
+                    <TableCell className="py-1 text-xs text-[var(--dg-text-muted)]">{b.note || '-'}</TableCell>
+                  </TableRow>
+                ))}
+              </TableBody>
+            </Table>
+          </div>
+        )}
+      </CardContent>
+    </Card>
+  );
+}

frontend/src/pages/monitor/site-monitor/SiteTaskDetailPage.tsx

@@ -6,6 +6,7 @@ import { Badge } from '@/components/ui/badge';
 import type { SiteTask } from './helpers';
 import { fmtFrequency, normalizeProbeType } from './helpers';
 import { SiteResultsPanel } from './SiteResultsPanel';
+import { SiteContentPanel } from './SiteContentPanel';
 
 interface Props {
   task: SiteTask;
@@ -33,6 +34,9 @@ export function SiteTaskDetailPage({ task, onBack, onProbed }: Props) {
         </div>
       </div>
 
+      {/* 内容监控：仅在任务启用时渲染，未启用时组件内部返回 null // Logan.Li */}
+      <SiteContentPanel taskId={task.id} />
+
       <SiteResultsPanel task={task} onProbed={onProbed} fullPage />
     </div>
   );

frontend/src/pages/monitor/site-monitor/helpers.ts

@@ -21,6 +21,15 @@ export interface SiteTask {
   created_at: string;
   ssl_days_remaining?: number;
   ssl_cert_expiry?: string;
+  // 内容监控 // Logan.Li
+  content_check_mode?: string;
+  content_paths?: string;
+  content_ignore_rules?: string;
+  content_min_length?: number;
+  content_confirm_times?: number;
+  content_sort_lines?: boolean;
+  current_baseline_id?: number;
+  pending_change_count?: number;
 }
 
 export interface SiteResult {