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<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>acme/web 中的认证流程</title>
<style>
:root {
--ivory: #FAF9F5;
--slate: #141413;
--clay: #D97757;
--oat: #E3DACC;
--olive: #788C5D;
--rust: #B04A3F;
--gray-150: #F0EEE6;
--gray-300: #D1CFC5;
--gray-500: #87867F;
--gray-700: #3D3D3A;
--serif: ui-serif, Georgia, 'Times New Roman', serif;
--sans: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
--mono: ui-monospace, 'SF Mono', Menlo, Monaco, monospace;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
body {
background: var(--ivory);
color: var(--gray-700);
font-family: var(--sans);
font-size: 15px;
line-height: 1.65;
padding: 48px 24px 80px;
}
.page {
max-width: 1080px;
margin: 0 auto;
display: grid;
grid-template-columns: minmax(0, 1fr) 280px;
gap: 40px;
}
@media (max-width: 960px) {
.page { grid-template-columns: 1fr; }
}
/* ---------- Header ---------- */
header {
grid-column: 1 / -1;
margin-bottom: 8px;
}
.repo-line {
font-family: var(--mono);
font-size: 12.5px;
color: var(--gray-500);
margin-bottom: 10px;
}
h1 {
font-family: var(--serif);
font-weight: 500;
font-size: 32px;
line-height: 1.25;
color: var(--slate);
margin-bottom: 16px;
}
.summary {
max-width: 760px;
font-size: 15.5px;
}
.summary code { font-family: var(--mono); font-size: 13px; }
h2 {
font-family: var(--serif);
font-weight: 500;
font-size: 22px;
color: var(--slate);
margin: 36px 0 16px;
}
/* ---------- Diagram ---------- */
.diagram-panel {
border: 1.5px solid var(--gray-300);
border-radius: 12px;
background: #fff;
padding: 20px;
overflow-x: auto;
}
svg.flow { display: block; max-width: 100%; }
.flow text {
font-family: var(--mono);
font-size: 12px;
fill: var(--slate);
}
.flow .sub { font-size: 10px; fill: var(--gray-500); }
.flow .box { fill: #fff; stroke: var(--gray-300); stroke-width: 1.5; }
.flow .box.hot { fill: rgba(217,119,87,0.10); stroke: var(--clay); }
.flow .arrow { stroke: var(--gray-500); stroke-width: 1.5; fill: none; }
/* ---------- Walkthrough ---------- */
.step {
display: grid;
grid-template-columns: 44px 1fr;
gap: 18px;
padding: 20px 0;
border-bottom: 1.5px solid var(--gray-150);
}
.step:last-of-type { border-bottom: none; }
.badge {
width: 34px;
height: 34px;
border-radius: 50%;
background: var(--oat);
border: 1.5px solid var(--gray-300);
display: flex;
align-items: center;
justify-content: center;
font-family: var(--mono);
font-weight: 600;
color: var(--slate);
font-size: 14px;
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.step.hot .badge {
background: rgba(217,119,87,0.14);
border-color: var(--clay);
color: var(--clay);
}
.step-loc {
font-family: var(--mono);
font-size: 13px;
color: var(--slate);
margin-bottom: 6px;
}
.step-loc .range { color: var(--gray-500); }
.step-body p { margin-bottom: 10px; }
details.snippet { margin-top: 6px; }
details.snippet summary {
list-style: none;
cursor: pointer;
font-size: 12.5px;
color: var(--gray-500);
font-family: var(--mono);
display: inline-flex;
align-items: center;
gap: 6px;
padding: 4px 0;
user-select: none;
}
details.snippet summary::-webkit-details-marker { display: none; }
details.snippet summary::before {
content: "▸";
font-size: 10px;
transition: transform 0.15s ease;
}
details.snippet[open] summary::before { transform: rotate(90deg); }
pre.code {
background: var(--slate);
color: #E8E6DC;
font-family: var(--mono);
font-size: 12.5px;
line-height: 1.7;
border-radius: 8px;
padding: 14px 16px;
overflow-x: auto;
margin-top: 10px;
}
pre.code .dim { color: var(--gray-500); }
pre.code .kw { color: #C9B98A; }
pre.code .str { color: #A8BC8C; }
/* ---------- Sidebar ---------- */
aside {
position: sticky;
top: 24px;
align-self: start;
}
.panel {
border: 1.5px solid var(--gray-300);
border-radius: 12px;
background: #fff;
padding: 18px 20px;
margin-bottom: 20px;
}
.panel h3 {
font-family: var(--sans);
font-size: 11px;
font-weight: 600;
text-transform: uppercase;
letter-spacing: 0.08em;
color: var(--gray-500);
margin-bottom: 12px;
}
.key-files { list-style: none; padding: 0; }
.key-files li { margin-bottom: 12px; }
.key-files li:last-child { margin-bottom: 0; }
.key-files .path {
font-family: var(--mono);
font-size: 12px;
color: var(--slate);
display: block;
margin-bottom: 2px;
word-break: break-all;
}
.key-files .desc {
font-size: 12.5px;
color: var(--gray-500);
line-height: 1.45;
}
.gotchas {
border: 1.5px solid var(--clay);
border-radius: 12px;
background: rgba(217,119,87,0.06);
padding: 18px 20px;
}
.gotchas h3 {
font-family: var(--sans);
font-size: 11px;
font-weight: 700;
text-transform: uppercase;
letter-spacing: 0.08em;
color: var(--clay);
margin-bottom: 10px;
}
.gotchas ul { list-style: none; padding: 0; }
.gotchas li {
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padding-left: 16px;
font-size: 13px;
margin-bottom: 8px;
}
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content: "";
position: absolute;
left: 0; top: 8px;
width: 5px; height: 5px;
background: var(--clay);
border-radius: 2px;
}
.gotchas code { font-family: var(--mono); font-size: 11.5px; }
</style>
</head>
<body>
<div class="page">
<header>
<div class="repo-line">acme/web · 架构笔记</div>
<h1>认证在代码库中如何流转</h1>
<p class="summary">
Acme 使用基于 cookie 的会话机制：浏览器不直接持有 bearer token。每个需要认证的请求都会打到 <code>/api/*</code>，经过唯一的 <code>verifyToken()</code> 中间件，解析到一行 <code>Session</code> 记录，下游 handler 从 <code>req.ctx</code> 上读取它。中间件是唯一跟 session store 打交道的地方，而 session store 是唯一跟 <code>sessions</code> 表打交道的地方，所以你只需要关注一条信任边界。
</p>
</header>
<main>
<h2 style="margin-top:0">请求路径</h2>
<div class="diagram-panel">
<svg class="flow" viewBox="0 0 720 280" width="720" height="280" role="img" aria-label="Authentication flow diagram">
<defs>
<marker id="arrowHead" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">
<path d="M 0 0 L 10 5 L 0 10 z" fill="#87867F"></path>
</marker>
</defs>
<!-- Row 1 -->
<g>
<rect class="box" x="30" y="40" width="150" height="64" rx="10"></rect>
<text x="105" y="68" text-anchor="middle">Browser</text>
<text class="sub" x="105" y="84" text-anchor="middle">acme.app</text>
</g>
<g>
<rect class="box" x="245" y="40" width="150" height="64" rx="10"></rect>
<text x="320" y="68" text-anchor="middle">/api/session</text>
<text class="sub" x="320" y="84" text-anchor="middle">route handler</text>
</g>
<g>
<rect class="box hot" x="460" y="40" width="180" height="64" rx="10"></rect>
<text x="550" y="68" text-anchor="middle">verifyToken()</text>
<text class="sub" x="550" y="84" text-anchor="middle">middleware/auth.ts</text>
</g>
<!-- Row 2 -->
<g>
<rect class="box" x="460" y="170" width="180" height="64" rx="10"></rect>
<text x="550" y="198" text-anchor="middle">SessionStore</text>
<text class="sub" x="550" y="214" text-anchor="middle">lib/sessionStore.ts</text>
</g>
<g>
<rect class="box" x="245" y="170" width="150" height="64" rx="10"></rect>
<text x="320" y="198" text-anchor="middle">Postgres</text>
<text class="sub" x="320" y="214" text-anchor="middle">sessions table</text>
</g>
<!-- Arrows -->
<line class="arrow" x1="180" y1="72" x2="245" y2="72" marker-end="url(#arrowHead)"></line>
<line class="arrow" x1="395" y1="72" x2="460" y2="72" marker-end="url(#arrowHead)"></line>
<line class="arrow" x1="550" y1="104" x2="550" y2="170" marker-end="url(#arrowHead)"></line>
<line class="arrow" x1="460" y1="202" x2="395" y2="202" marker-end="url(#arrowHead)"></line>
<text class="sub" x="212" y="62" text-anchor="middle">cookie</text>
<text class="sub" x="560" y="140" text-anchor="start">lookup</text>
</svg>
</div>
<h2>调用栈逐步解析</h2>
<!-- Step 1 -->
<div class="step">
<div class="badge">1</div>
<div class="step-body">
<div class="step-loc">src/app/providers/AuthProvider.tsx<span class="range"> :22-48</span></div>
<p>组件挂载时，React provider 发起 <code style="font-family:var(--mono);font-size:12.5px">GET /api/session</code> 请求，带上 <code style="font-family:var(--mono);font-size:12.5px">credentials: 'include'</code>，这样 <code style="font-family:var(--mono);font-size:12.5px">fw_sid</code> cookie 会自动附带。响应要么把 <code style="font-family:var(--mono);font-size:12.5px">currentUser</code> 注入上下文，要么留空为 <code style="font-family:var(--mono);font-size:12.5px">null</code>，路由层会据此显示登录页面。</p>
<details class="snippet">
<summary>查看源码</summary>
<pre class="code"><span class="dim">// src/app/providers/AuthProvider.tsx</span>
<span class="kw">export function</span> AuthProvider({ children }: Props) {
<span class="kw">const</span> [user, setUser] = useState<User | <span class="kw">null</span>>(<span class="kw">null</span>);
useEffect(() => {
fetch(<span class="str">'/api/session'</span>, { credentials: <span class="str">'include'</span> })
.then(r => r.ok ? r.json() : <span class="kw">null</span>)
.then(setUser);
}, []);
<span class="kw">return</span> <AuthCtx.Provider value={{ user }}>{children}</AuthCtx.Provider>;
}</pre>
</details>
</div>
</div>
<!-- Step 2 -->
<div class="step">
<div class="badge">2</div>
<div class="step-body">
<div class="step-loc">src/server/routes/session.ts<span class="range"> :9-27</span></div>
<p>这个路由本身很薄：只返回中间件附加在 <code style="font-family:var(--mono);font-size:12.5px">req.ctx.session</code> 上的内容。如果中间件已经返回了 401，这个 handler 根本不会执行，所以这里没有重复的认证逻辑。</p>
<details class="snippet">
<summary>查看源码</summary>
<pre class="code"><span class="dim">// src/server/routes/session.ts</span>
router.get(<span class="str">'/session'</span>, verifyToken, (req, res) => {
<span class="kw">const</span> { session } = req.ctx;
res.json({
id: session.userId,
email: session.email,
role: session.role,
exp: session.expiresAt,
});
});</pre>
</details>
</div>
</div>
<!-- Step 3 -->
<div class="step hot">
<div class="badge">3</div>
<div class="step-body">
<div class="step-loc">src/middleware/auth.ts<span class="range"> :14-31</span></div>
<p>这里是信任边界。<code style="font-family:var(--mono);font-size:12.5px">verifyToken</code> 读取签名的 <code style="font-family:var(--mono);font-size:12.5px">fw_sid</code> cookie，让 <code style="font-family:var(--mono);font-size:12.5px">SessionStore</code> 去解析，然后要么填充 <code style="font-family:var(--mono);font-size:12.5px">req.ctx.session</code>，要么返回 401。应用里所有受保护的路由都挂在这个函数后面，改它就等于改了全局认证行为。</p>
<details class="snippet" open>
<summary>查看源码</summary>
<pre class="code"><span class="dim">// src/middleware/auth.ts</span>
<span class="kw">export async function</span> verifyToken(req, res, next) {
<span class="kw">const</span> raw = req.signedCookies[<span class="str">'fw_sid'</span>];
<span class="kw">if</span> (!raw) <span class="kw">return</span> res.status(401).end();
<span class="kw">const</span> session = <span class="kw">await</span> SessionStore.get(raw);
<span class="kw">if</span> (!session || session.expiresAt < Date.now()) {
<span class="kw">return</span> res.status(401).end();
}
req.ctx = { session };
next();
}</pre>
</details>
</div>
</div>
<!-- Step 4 -->
<div class="step">
<div class="badge">4</div>
<div class="step-body">
<div class="step-loc">src/lib/sessionStore.ts<span class="range"> :8-52</span></div>
<p><code style="font-family:var(--mono);font-size:12.5px">SessionStore</code> 是一个小型读穿缓存：先查进程内 LRU，命中就返回，未命中则回退到 Postgres。写操作（<code style="font-family:var(--mono);font-size:12.5px">create</code>、<code style="font-family:var(--mono);font-size:12.5px">revoke</code>）始终直接写库并清除对应缓存条目，以防其他 worker 继续使用过期会话。</p>
<details class="snippet">
<summary>查看源码</summary>
<pre class="code"><span class="dim">// src/lib/sessionStore.ts</span>
<span class="kw">const</span> cache = <span class="kw">new</span> LRU<string, Session>({ max: 5000, ttl: 60_000 });
<span class="kw">export const</span> SessionStore = {
<span class="kw">async</span> get(id: string) {
<span class="kw">const</span> hit = cache.get(id);
<span class="kw">if</span> (hit) <span class="kw">return</span> hit;
<span class="kw">const</span> row = <span class="kw">await</span> db.one(SELECT_SESSION, [id]);
<span class="kw">if</span> (row) cache.set(id, row);
<span class="kw">return</span> row ?? <span class="kw">null</span>;
},
<span class="dim">/* create, revoke, touch ... */</span>
};</pre>
</details>
</div>
</div>
<!-- Step 5 -->
<div class="step">
<div class="badge">5</div>
<div class="step-body">
<div class="step-loc">db/migrations/004_sessions.sql<span class="range"> :1-18</span></div>
<p><code style="font-family:var(--mono);font-size:12.5px">sessions</code> 表以随机 32 字节 id（即 cookie 值）为主键，在 <code style="font-family:var(--mono);font-size:12.5px">user_id</code> 上建了覆盖索引，用于「全部登出」功能。过期策略在这里（<code style="font-family:var(--mono);font-size:12.5px">expires_at</code>）和中间件中都有强制执行，做双重防护。</p>
<details class="snippet">
<summary>查看源码</summary>
<pre class="code"><span class="dim">-- db/migrations/004_sessions.sql</span>
<span class="kw">create table</span> sessions (
id <span class="kw">text primary key</span>,
user_id <span class="kw">uuid not null references</span> users(id),
created_at <span class="kw">timestamptz default</span> now(),
expires_at <span class="kw">timestamptz not null</span>,
ip <span class="kw">inet</span>,
user_agent <span class="kw">text</span>
);
<span class="kw">create index</span> sessions_user_id_idx <span class="kw">on</span> sessions(user_id);</pre>
</details>
</div>
</div>
</main>
<aside>
<div class="panel">
<h3>关键文件</h3>
<ul class="key-files">
<li>
<span class="path">src/middleware/auth.ts</span>
<span class="desc">请求认证的唯一入口。</span>
</li>
<li>
<span class="path">src/lib/sessionStore.ts</span>
<span class="desc">LRU + Postgres 会话查找；唯一的数据库调用方。</span>
</li>
<li>
<span class="path">src/server/routes/session.ts</span>
<span class="desc">向客户端返回当前会话。</span>
</li>
<li>
<span class="path">src/server/routes/login.ts</span>
<span class="desc">通过 SessionStore.create 将凭证换成 cookie。</span>
</li>
<li>
<span class="path">src/app/providers/AuthProvider.tsx</span>
<span class="desc">镜像服务端会话的客户端上下文。</span>
</li>
<li>
<span class="path">db/migrations/004_sessions.sql</span>
<span class="desc">sessions 表和索引的 Schema。</span>
</li>
</ul>
</div>
<div class="gotchas">
<h3>注意事项</h3>
<ul>
<li><code>SessionStore</code> 的 LRU 是进程级的。撤销会话只会清除本地缓存，其他 worker 可能在 TTL（60 秒）过期前继续使用该会话。</li>
<li><code>verifyToken</code> 用 <code>Date.now()</code> 比较 <code>expiresAt</code>，但该列类型是 <code>timestamptz</code>。驱动返回的是 <code>Date</code> 对象，所以比较能正常工作。但如果重构成原始字符串比较，就要同步调整逻辑。</li>
</ul>
</div>
</aside>
</div>
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