feat: 内置 HTML 预览器 + 沙箱浏览器 tab（v0.5.0）

- html viewer：.html/.htm 沙箱 iframe 预览（相对资源经 /sidebar/html 路径编码路由加载，CSP sandbox + 信任围栏 + cwd 边界），预览/编辑切换 - browser tab：+ 菜单多开（browser:<n>），地址栏后退/前进/刷新/在浏览器中打开（15px 图标），URL 与标题按会话持久化（patchTab + nextBrowser） - 安全：iframe 一律不透明源沙箱（无 allow-same-origin/top-navigation、no-referrer、权限策略全禁、禁 srcdoc）；地址栏仅 http(s)、拒绝 localhost 等本机地址；界面实时沙箱状态（关闭红色警示）+ 临时解锁/恢复 - 设置：htmlViewerNoSandbox / htmlViewerDefaultUnsafe / browserNoSandbox / browserInterceptLinks 四个声明式二级设置（默认安全） - 外链拦截：聊天/界面 http(s) 外链默认在侧边栏打开（openTab seed.url），Ctrl/Cmd 点击放行 - 嵌入拒绝面板：browser.probe 路由探测 X-Frame-Options/frame-ancestors，被拒站点显示原因 + 在浏览器中打开/仍然加载 - 设置页可滚动；内置 7 tab + 9 viewer；新增设计文档；268 个测试全绿
2026-08-11 19:28:48 +08:00
parent 35cde82eb2
commit 302c20109f
36 changed files with 2084 additions and 58 deletions
@@ -0,0 +1,119 @@
+/**
+ * Pure URL policy for the built-in browser tab: normalize user input into
+ * an http(s) URL, and refuse destinations that would be dangerous to embed
+ * in the sidebar iframe. Kept dependency-free so it is unit-testable.
+ *
+ * The iframe sandbox (opaque origin, no allow-same-origin / top-navigation)
+ * is the primary security boundary; this module is the address-bar gate on
+ * top of it: only http/https may be navigated, and loopback addresses are
+ * refused so a browsed page cannot probe local services by user action.
+ * The GUI's OWN origin is explicitly ALLOWED — the user may open the GUI
+ * itself in the sidebar (debugging, mirroring); the sandbox still renders
+ * it in an opaque origin with no same-origin privileges, exactly like any
+ * other site.
+ */
+
+/** Why a navigation attempt was refused. */
+export type BrowserBlockReason = 'scheme' | 'loopback'
+
+/** Result of normalizing one address-bar input. */
+export type BrowserNavigateResult =
+  | { kind: 'ok'; url: string }
+  | { kind: 'blocked'; reason: BrowserBlockReason }
+  | { kind: 'invalid' }
+
+/** One browser.probe wire result (host fetch of the target's headers). */
+export interface BrowserProbeResult {
+  reachable: boolean
+  /** The final (post-redirect) URL; present when reachable. */
+  url?: string
+  status?: number
+  xFrameOptions?: string
+  /** The CSP frame-ancestors source list; present when the directive exists. */
+  frameAncestors?: string[]
+}
+
+/** Embeddability verdict of one probe. */
+export type Embeddability = 'embeddable' | 'blocked' | 'unknown'
+
+/**
+ * Decide whether a site can render inside the sidebar iframe. The signals
+ * are exactly the ones the BROWSER enforces when it refuses an iframe load:
+ * X-Frame-Options DENY/SAMEORIGIN, or a frame-ancestors directive that does
+ * not allow `*` ('self' here means the SITE's own origin — never ours, so
+ * it also blocks the sidebar). A site we could not reach yields 'unknown'
+ * and the plain iframe stays.
+ */
+export function embeddabilityOf(probe: BrowserProbeResult): Embeddability {
+  if (probe.reachable !== true) return 'unknown'
+  const xfo = probe.xFrameOptions?.trim().toUpperCase()
+  if (xfo === 'DENY' || xfo === 'SAMEORIGIN') return 'blocked'
+  if (probe.frameAncestors !== undefined && !probe.frameAncestors.some(source => source === '*')) return 'blocked'
+  return 'embeddable'
+}
+
+/** A loopback hostname (localhost, IPv6 ::1, 127.0.0.0/8, 0.0.0.0). */
+export function isLoopbackHostname(hostname: string): boolean {
+  const host = hostname.replace(/^\[|\]$/g, '').toLowerCase()
+  if (host === 'localhost' || host === '::1' || host === '0.0.0.0') return true
+  const parts = host.split('.')
+  return parts.length === 4
+    && parts[0] === '127'
+    && parts.every(part => /^\d{1,3}$/.test(part) && Number(part) <= 255)
+}
+
+/**
+ * Normalize one address-bar input against the navigation policy.
+ * @param input - raw user text.
+ * @param selfOrigin - the GUI's own origin (window.location.origin). The GUI
+ * itself may be browsed in the sidebar (the sandbox keeps it opaque), so it
+ * is let through BEFORE the loopback check — its host is normally loopback.
+ */
+/** Schemes that must never reach the iframe, even without `//` (javascript:,
+ *  data:, file:, ...). Host:port lookalikes (example.com:8080) are NOT here —
+ *  they parse as hosts below. */
+const FORBIDDEN_SCHEMES = new Set([
+  'javascript', 'data', 'file', 'about', 'vbscript', 'blob',
+  'mailto', 'tel', 'ftp', 'ftps', 'ws', 'wss', 'sftp', 'ssh',
+  'chrome', 'chrome-extension', 'moz-extension', 'edge', 'opera', 'resource', 'view-source',
+])
+
+export function normalizeBrowserUrl(input: string, selfOrigin: string): BrowserNavigateResult {
+  const trimmed = input.trim()
+  if (trimmed === '') return { kind: 'invalid' }
+  // Distinguish an explicit scheme from a bare host:port. "example.com:8080"
+  // would match a naive scheme regex (dots are legal in schemes), so a
+  // scheme prefix is only honored when it is http(s) or a known-forbidden
+  // scheme; anything else is treated as a host and gets https://.
+  const schemeMatch = /^([a-zA-Z][a-zA-Z0-9+.-]*):/.exec(trimmed)
+  let withScheme: string
+  if (schemeMatch === null) {
+    withScheme = `https://${trimmed}`
+  } else {
+    const scheme = schemeMatch[1]!.toLowerCase()
+    if (scheme === 'http' || scheme === 'https') withScheme = trimmed
+    else if (FORBIDDEN_SCHEMES.has(scheme)) return { kind: 'blocked', reason: 'scheme' }
+    else withScheme = `https://${trimmed}`
+  }
+  let url: URL
+  try {
+    url = new URL(withScheme)
+  } catch {
+    return { kind: 'invalid' }
+  }
+  // The protocol backstop: any URL that still parses to a non-http(s)
+  // scheme (e.g. ftp://, ws:// — which carry `//` and skip the list) is
+  // refused here.
+  if (url.protocol !== 'http:' && url.protocol !== 'https:') return { kind: 'blocked', reason: 'scheme' }
+  // The GUI's own origin is ALLOWED (the user may browse the GUI itself in
+  // the sidebar; the sandbox renders it in an opaque origin like any other
+  // site). It must be checked before the loopback gate because its host is
+  // normally loopback.
+  try {
+    if (url.origin === new URL(selfOrigin).origin) return { kind: 'ok', url: url.href }
+  } catch {
+    // Unparsable selfOrigin (never in practice): fall through to the loopback gate.
+  }
+  if (isLoopbackHostname(url.hostname)) return { kind: 'blocked', reason: 'loopback' }
+  return { kind: 'ok', url: url.href }
+}