Modelo do encurtador em Express

Gerado a partir de deploy-templates/express (dado.cloud 4c2a882).
2026-10-21 12:27:02 +00:00
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+node_modules/
+.env
+.DS_Store
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+# Encurtador de links em Express
+
+Um encurtador de links pronto para publicar na [Dado](https://dado.cloud): cole um link
+comprido, receba um endereço curto e acompanhe quantas vezes ele foi aberto.
+
+Este repositório nasceu de um modelo da Dado. Cada `git push` na branch `main` publica
+uma versão nova do seu app, sozinho.
+
+## O que tem aqui
+
+- `server.js`: o servidor — página, API (`POST/GET /api/links`) e o redirecionamento `GET /<código>` (302).
+- `links.js`: onde os links ficam guardados (na memória) e a validação dos endereços.
+- `paginas/index.html`: a página (HTML, CSS e o JavaScript do formulário). Mude à vontade.
+- `paginas/nao-encontrado.html`: a página de link que não existe.
+
+Não tem banco de dados: os links ficam na memória do app e **somem quando ele é publicado
+de novo**. Veja no fim como guardar de vez.
+
+## Rodar no seu computador
+
+Precisa de Node.js 20 ou mais novo.
+
+```bash
+git clone https://git.dado.cloud/<sua-conta>/encurtador-express.git
+cd encurtador-express
+npm install
+npm run dev
+```
+
+Abra http://localhost:3000.
+
+Quando o `git clone` pedir usuário e senha, use o usuário da sua conta de Repositórios e,
+como senha, o **token de Repositórios** (no painel da Dado, em Repositórios). O comando
+certinho do seu app aparece no painel, em Deploys, na visão geral do app.
+
+## Mudar e publicar
+
+Edite o que quiser e mande para a Dado:
+
+```bash
+git add .
+git commit -m "Minha primeira mudança"
+git push
+```
+
+O push na branch `main` publica uma versão nova. Dá para acompanhar o andamento em
+Deploys, no painel.
+
+## Variável de ambiente de exemplo
+
+A mensagem em "Sobre este deploy" vem da variável `MENSAGEM_BOAS_VINDAS`. Para trocar,
+abra Deploys no painel, clique em "Variáveis de ambiente" no seu app, salve e publique de
+novo. No seu computador:
+
+```bash
+MENSAGEM_BOAS_VINDAS="Oi, mundo" npm run dev
+```
+
+## API
+
+```bash
+# Encurtar
+curl -X POST https://<endereço-do-seu-app>/api/links \
+  -H 'Content-Type: application/json' \
+  -d '{"url": "https://exemplo.com.br/uma-pagina"}'
+# 201 {"codigo":"a1b2c3","url":"https://exemplo.com.br/uma-pagina","curto":"https://<endereço-do-seu-app>/a1b2c3","cliques":0,"criadoEm":"..."}
+
+# Últimos 20 links
+curl https://<endereço-do-seu-app>/api/links
+# 200 {"links":[...]}
+```
+
+`GET /<código>` redireciona (302) para o link original e soma um clique. A API aceita
+chamadas de qualquer site (CORS aberto só em `/api/*`), então outro app seu pode usá-la.
+Para evitar abuso, cada IP cria no máximo 30 links a cada 10 minutos.
+
+## Guardar os links de vez
+
+Para os links sobreviverem a uma nova publicação, ligue um Postgres no app (painel, em
+Deploys, aba "Banco de dados" do app). A conexão chega ao app na variável `DATABASE_URL`;
+aí é trocar o que está em `links.js` por consultas ao banco.
@@ -0,0 +1,69 @@
+import { randomInt } from 'node:crypto';
+
+// Os links ficam num Map na memória do processo: simples e sem banco, mas
+// somem toda vez que o app reinicia ou é publicado de novo. Para guardar de
+// vez, troque este arquivo por consultas a um Postgres.
+
+const ALFABETO = 'abcdefghijklmnopqrstuvwxyz0123456789';
+const TAMANHO_CODIGO = 6;
+const TAMANHO_MAXIMO_URL = 2048;
+// Teto de links guardados: passou disso, o mais antigo sai (protege a memória).
+const MAXIMO_DE_LINKS = 1000;
+const LINKS_NA_LISTA = 20;
+// Caminhos do próprio app que nunca podem virar código.
+const RESERVADOS = new Set(['api']);
+
+export const FORMATO_CODIGO = /^[a-z0-9]{6}$/;
+
+const links = new Map();
+
+export class ErroDeValidacao extends Error {}
+
+function gerarCodigo() {
+  for (;;) {
+    let codigo = '';
+    for (let i = 0; i < TAMANHO_CODIGO; i += 1) codigo += ALFABETO[randomInt(ALFABETO.length)];
+    if (!links.has(codigo) && !RESERVADOS.has(codigo)) return codigo;
+  }
+}
+
+function validarUrl(valor) {
+  if (typeof valor !== 'string' || valor.trim() === '') {
+    throw new ErroDeValidacao('Envie o campo "url" com o link que você quer encurtar.');
+  }
+  const texto = valor.trim();
+  if (texto.length > TAMANHO_MAXIMO_URL) {
+    throw new ErroDeValidacao(`Esse link é comprido demais (máximo de ${TAMANHO_MAXIMO_URL} caracteres).`);
+  }
+  let url;
+  try {
+    url = new URL(texto);
+  } catch {
+    url = null;
+  }
+  if (!url || (url.protocol !== 'http:' && url.protocol !== 'https:')) {
+    throw new ErroDeValidacao('Esse não parece um link válido. Use um endereço que comece com http:// ou https://.');
+  }
+  return url.href;
+}
+
+export function criarLink(valor) {
+  const url = validarUrl(valor);
+  const link = { codigo: gerarCodigo(), url, cliques: 0, criadoEm: new Date().toISOString() };
+  links.set(link.codigo, link);
+  if (links.size > MAXIMO_DE_LINKS) links.delete(links.keys().next().value);
+  return link;
+}
+
+/** Os últimos links criados, do mais novo para o mais antigo. */
+export function listarLinks() {
+  return [...links.values()].slice(-LINKS_NA_LISTA).reverse();
+}
+
+/** Soma um clique e devolve o link, ou null se o código não existe. */
+export function registrarClique(codigo) {
+  const link = links.get(codigo);
+  if (!link) return null;
+  link.cliques += 1;
+  return link;
+}
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+      },
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+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
+    "node_modules/toidentifier": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/toidentifier/-/toidentifier-1.0.1.tgz",
+      "integrity": "sha512-o5sSPKEkg/DIQNmH43V0/uerLrpzVedkUh8tGNvaeXpfpuwjKenlSox/2O/BTlZUtEe+JG7s5YhEz608PlAHRA==",
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.6"
+      }
+    },
+    "node_modules/type-is": {
+      "version": "2.1.0",
+      "resolved": "https://registry.npmjs.org/type-is/-/type-is-2.1.0.tgz",
+      "integrity": "sha512-faYHw0anBbc/kWF3zFTEnxSFOAGUX9GFbOBthvDdLsIlEoWOFOtS0zgCiQYwIskL9iGXZL3kAXD8OoZ4GmMATA==",
+      "license": "MIT",
+      "dependencies": {
+        "content-type": "^2.0.0",
+        "media-typer": "^1.1.0",
+        "mime-types": "^3.0.0"
+      },
+      "engines": {
+        "node": ">= 18"
+      },
+      "funding": {
+        "type": "opencollective",
+        "url": "https://opencollective.com/express"
+      }
+    },
+    "node_modules/unpipe": {
+      "version": "1.0.0",
+      "resolved": "https://registry.npmjs.org/unpipe/-/unpipe-1.0.0.tgz",
+      "integrity": "sha512-pjy2bYhSsufwWlKwPc+l3cN7+wuJlK6uz0YdJEOlQDbl6jo/YlPi4mb8agUkVC8BF7V8NuzeyPNqRksA3hztKQ==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
+    "node_modules/vary": {
+      "version": "1.1.2",
+      "resolved": "https://registry.npmjs.org/vary/-/vary-1.1.2.tgz",
+      "integrity": "sha512-BNGbWLfd0eUPabhkXUVm0j8uuvREyTh5ovRa/dyow/BqAbZJyC+5fU+IzQOzmAKzYqYRAISoRhdQr3eIZ/PXqg==",
+      "license": "MIT",
+      "engines": {
+        "node": ">= 0.8"
+      }
+    },
+    "node_modules/wrappy": {
+      "version": "1.0.2",
+      "resolved": "https://registry.npmjs.org/wrappy/-/wrappy-1.0.2.tgz",
+      "integrity": "sha512-l4Sp/DRseor9wL6EvV2+TuQn63dMkPjZ/sp9XkghTEbV9KlPS1xUsZ3u7/IQO4wxtcFB4bgpQPRcR3QCvezPcQ==",
+      "license": "ISC"
+    }
+  }
+}
@@ -0,0 +1,18 @@
+{
+  "name": "encurtador-express",
+  "version": "1.0.0",
+  "private": true,
+  "description": "Encurtador de links em Express, pronto para publicar na Dado.",
+  "type": "module",
+  "main": "server.js",
+  "scripts": {
+    "dev": "node --watch server.js",
+    "start": "node server.js"
+  },
+  "engines": {
+    "node": ">=20"
+  },
+  "dependencies": {
+    "express": "5.3.0"
+  }
+}
@@ -0,0 +1,278 @@
+<!doctype html>
+<html lang="pt-BR">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <title>Encurtador de links</title>
+    <meta name="description" content="Encurte links e acompanhe quantas vezes cada um foi aberto." />
+    <link
+      rel="icon"
+      href="data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 32 32'%3E%3Crect width='32' height='32' rx='8' fill='%233b5bdb'/%3E%3Cpath d='M13.5 18.5l5-5M12 15l-2 2a3.5 3.5 0 005 5l2-2M20 17l2-2a3.5 3.5 0 00-5-5l-2 2' stroke='white' stroke-width='2.2' fill='none' stroke-linecap='round'/%3E%3C/svg%3E"
+    />
+    <style>
+      /* Mesmo visual nos modelos Next.js, Express e FastAPI. Mude à vontade. */
+      :root {
+        --fundo: #f6f7f9;
+        --cartao: #ffffff;
+        --texto: #14161a;
+        --suave: #5b6270;
+        --borda: #e3e6eb;
+        --destaque: #3b5bdb;
+        --destaque-texto: #ffffff;
+        --destaque-suave: #edf1ff;
+        --erro: #c92a2a;
+        --raio: 14px;
+        --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
+        color-scheme: light dark;
+      }
+      @media (prefers-color-scheme: dark) {
+        :root {
+          --fundo: #0f1115;
+          --cartao: #171a21;
+          --texto: #eceef2;
+          --suave: #9aa1ad;
+          --borda: #2a2f3a;
+          --destaque: #8299ff;
+          --destaque-texto: #0f1115;
+          --destaque-suave: #1e2540;
+          --erro: #ff8787;
+        }
+      }
+      * { box-sizing: border-box; }
+      body {
+        margin: 0;
+        font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
+        background: var(--fundo);
+        color: var(--texto);
+        line-height: 1.5;
+        -webkit-text-size-adjust: 100%;
+      }
+      .pagina { max-width: 640px; margin: 0 auto; padding: 56px 16px 32px; }
+      .topo { display: flex; align-items: center; gap: 12px; margin-bottom: 8px; }
+      .marca {
+        flex: none; width: 40px; height: 40px; border-radius: 10px;
+        background: var(--destaque); color: var(--destaque-texto);
+        display: grid; place-items: center;
+      }
+      h1 { font-size: 28px; line-height: 1.2; margin: 0; letter-spacing: -0.02em; }
+      h2 { font-size: 16px; margin: 32px 0 12px; }
+      .lead { color: var(--suave); margin: 0 0 24px; }
+      .cartao { background: var(--cartao); border: 1px solid var(--borda); border-radius: var(--raio); padding: 20px; }
+      .formulario { display: flex; gap: 8px; }
+      .formulario input {
+        flex: 1; min-width: 0; font: inherit; padding: 12px 14px;
+        border: 1px solid var(--borda); border-radius: 10px;
+        background: var(--fundo); color: var(--texto);
+      }
+      .formulario input:focus { outline: 2px solid var(--destaque); outline-offset: 1px; }
+      button {
+        font: inherit; font-weight: 600; padding: 12px 20px; border: 0; border-radius: 10px;
+        background: var(--destaque); color: var(--destaque-texto); cursor: pointer; white-space: nowrap;
+      }
+      button:disabled { opacity: 0.6; cursor: progress; }
+      button:focus-visible, a:focus-visible { outline: 2px solid var(--destaque); outline-offset: 2px; }
+      .secundario { background: var(--cartao); color: var(--destaque); border: 1px solid var(--borda); padding: 8px 14px; }
+      .erro { color: var(--erro); margin: 10px 0 0; font-size: 14px; }
+      .resultado {
+        margin-top: 16px; display: flex; align-items: center; gap: 12px;
+        padding: 12px 14px; border-radius: 10px; background: var(--destaque-suave);
+      }
+      .resultado a {
+        flex: 1; min-width: 0; font-family: var(--mono); font-weight: 600;
+        color: var(--destaque); text-decoration: none; overflow-wrap: anywhere;
+      }
+      .lista { list-style: none; margin: 0; padding: 0; }
+      .lista li { display: flex; align-items: center; gap: 12px; padding: 12px 0; border-top: 1px solid var(--borda); }
+      .lista li:first-child { border-top: 0; padding-top: 0; }
+      .lista li:last-child { padding-bottom: 0; }
+      .link-info { flex: 1; min-width: 0; }
+      .link-info a { font-family: var(--mono); font-weight: 600; color: var(--texto); text-decoration: none; overflow-wrap: anywhere; }
+      .link-info a:hover { color: var(--destaque); }
+      .destino { display: block; color: var(--suave); font-size: 14px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
+      .cliques { font-family: var(--mono); font-size: 14px; color: var(--suave); white-space: nowrap; }
+      .vazio { color: var(--suave); margin: 0; }
+      .aviso {
+        margin: 16px 0 0; font-size: 14px; color: var(--suave);
+        border: 1px dashed var(--borda); border-radius: var(--raio); padding: 14px 16px;
+      }
+      .aviso a { color: var(--destaque); font-weight: 600; }
+      .sobre { margin-top: 32px; }
+      .sobre h2 { margin-top: 0; }
+      .sobre dl { display: grid; grid-template-columns: max-content 1fr; gap: 6px 16px; margin: 0; font-size: 14px; }
+      .sobre dt { color: var(--suave); }
+      .sobre dd { margin: 0; overflow-wrap: anywhere; }
+      .dica { font-size: 13px; color: var(--suave); margin: 14px 0 0; }
+      code { font-family: var(--mono); font-size: 0.92em; }
+      .rodape { margin-top: 32px; text-align: center; font-size: 13px; color: var(--suave); }
+      .rodape a { color: inherit; }
+      .so-leitor {
+        position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
+        overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0;
+      }
+      @media (max-width: 480px) {
+        .pagina { padding-top: 32px; }
+        h1 { font-size: 24px; }
+        .formulario { flex-direction: column; }
+        .resultado { flex-direction: column; align-items: stretch; }
+        .sobre dl { grid-template-columns: 1fr; gap: 0; }
+        .sobre dd { margin-bottom: 8px; }
+      }
+    </style>
+  </head>
+  <body>
+    <main class="pagina">
+      <header class="topo">
+        <span class="marca" aria-hidden="true">
+          <svg width="22" height="22" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.2" stroke-linecap="round">
+            <path d="M10 14l4-4M8.5 11.5l-1.8 1.8a3.2 3.2 0 004.5 4.5l1.8-1.8M15.5 12.5l1.8-1.8a3.2 3.2 0 00-4.5-4.5l-1.8 1.8" />
+          </svg>
+        </span>
+        <h1>Encurtador de links</h1>
+      </header>
+      <p class="lead">Cole um link comprido e receba um endereço curto, pronto para compartilhar.</p>
+
+      <section class="cartao">
+        <form id="formulario" class="formulario" novalidate>
+          <label for="url" class="so-leitor">Link para encurtar</label>
+          <input id="url" name="url" type="url" inputmode="url" maxlength="2048" placeholder="Cole seu link aqui" autocomplete="off" required />
+          <button type="submit" id="encurtar">Encurtar</button>
+        </form>
+        <p id="erro" class="erro" role="alert" hidden></p>
+        <div id="resultado" class="resultado" hidden>
+          <a id="curto" href="#" target="_blank" rel="noopener"></a>
+          <button type="button" id="copiar" class="secundario">Copiar</button>
+        </div>
+      </section>
+
+      <h2>Últimos links</h2>
+      <section class="cartao">
+        <ul id="lista" class="lista"></ul>
+        <p id="vazio" class="vazio">Nenhum link ainda. Encurte o primeiro aí em cima.</p>
+      </section>
+
+      <p class="aviso">
+        Os links ficam na memória do app e somem quando ele é publicado de novo.
+        Para guardar os links de vez, <a href="https://app.dado.cloud/deploys" target="_blank" rel="noopener">ligue um Postgres</a>.
+      </p>
+
+      <section class="sobre cartao" aria-labelledby="sobre-titulo">
+        <h2 id="sobre-titulo">Sobre este deploy</h2>
+        <dl>
+          <dt>Runtime</dt>
+          <dd>{{RUNTIME}}</dd>
+          <dt>Região</dt>
+          <dd>Rodando em São Paulo</dd>
+          <dt>No ar desde</dt>
+          <dd><time datetime="{{INICIO_ISO}}">{{INICIO}}</time></dd>
+          <dt>Mensagem</dt>
+          <dd>{{MENSAGEM}}</dd>
+        </dl>
+        <p class="dica">
+          A mensagem vem da variável <code>MENSAGEM_BOAS_VINDAS</code>. Troque o valor nas
+          configurações do app, no painel, e publique de novo.
+        </p>
+      </section>
+
+      <footer class="rodape">Publicado na <a href="https://dado.cloud" target="_blank" rel="noopener">Dado</a></footer>
+    </main>
+
+    <script>
+      const formulario = document.getElementById('formulario');
+      const campo = document.getElementById('url');
+      const botao = document.getElementById('encurtar');
+      const erro = document.getElementById('erro');
+      const resultado = document.getElementById('resultado');
+      const curto = document.getElementById('curto');
+      const copiar = document.getElementById('copiar');
+      const lista = document.getElementById('lista');
+      const vazio = document.getElementById('vazio');
+
+      const semProtocolo = (url) => url.replace(/^https?:\/\//, '');
+
+      function itemDaLista(link) {
+        const li = document.createElement('li');
+        const info = document.createElement('div');
+        info.className = 'link-info';
+        const a = document.createElement('a');
+        a.href = link.curto;
+        a.target = '_blank';
+        a.rel = 'noopener';
+        a.textContent = semProtocolo(link.curto);
+        const destino = document.createElement('span');
+        destino.className = 'destino';
+        destino.textContent = link.url;
+        destino.title = link.url;
+        info.append(a, destino);
+        const cliques = document.createElement('span');
+        cliques.className = 'cliques';
+        cliques.textContent = link.cliques === 1 ? '1 clique' : `${link.cliques} cliques`;
+        li.append(info, cliques);
+        return li;
+      }
+
+      async function carregarLinks() {
+        try {
+          const resposta = await fetch('/api/links', { cache: 'no-store' });
+          if (!resposta.ok) return;
+          const { links } = await resposta.json();
+          lista.replaceChildren(...links.map(itemDaLista));
+          vazio.hidden = links.length > 0;
+        } catch {
+          // Sem rede: a lista fica como estava.
+        }
+      }
+
+      function mostrarErro(mensagem) {
+        erro.textContent = mensagem;
+        erro.hidden = false;
+      }
+
+      formulario.addEventListener('submit', async (evento) => {
+        evento.preventDefault();
+        erro.hidden = true;
+        let url = campo.value.trim();
+        if (!url) return mostrarErro('Cole um link para encurtar.');
+        // Quem digita "exemplo.com.br" quer dizer https://exemplo.com.br.
+        if (!/^[a-z][a-z0-9+.-]*:/i.test(url)) url = `https://${url}`;
+
+        botao.disabled = true;
+        try {
+          const resposta = await fetch('/api/links', {
+            method: 'POST',
+            headers: { 'Content-Type': 'application/json' },
+            body: JSON.stringify({ url }),
+          });
+          const dados = await resposta.json().catch(() => ({}));
+          if (!resposta.ok) return mostrarErro(dados.erro || 'Não deu para encurtar esse link. Tente de novo.');
+          curto.href = dados.curto;
+          curto.textContent = semProtocolo(dados.curto);
+          copiar.textContent = 'Copiar';
+          resultado.hidden = false;
+          campo.value = '';
+          await carregarLinks();
+        } catch {
+          mostrarErro('Sem conexão com o servidor. Tente de novo.');
+        } finally {
+          botao.disabled = false;
+        }
+      });
+
+      copiar.addEventListener('click', async () => {
+        try {
+          await navigator.clipboard.writeText(curto.href);
+          copiar.textContent = 'Copiado!';
+        } catch {
+          // Navegador sem permissão de área de transferência: seleciona o link.
+          getSelection().selectAllChildren(curto);
+        }
+      });
+
+      // Voltou para a aba depois de testar um link? Atualiza a contagem de cliques.
+      document.addEventListener('visibilitychange', () => {
+        if (document.visibilityState === 'visible') carregarLinks();
+      });
+
+      carregarLinks();
+    </script>
+  </body>
+</html>
@@ -0,0 +1,32 @@
+<!doctype html>
+<html lang="pt-BR">
+  <head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1" />
+    <title>Link não encontrado</title>
+    <style>
+      :root { color-scheme: light dark; }
+      body {
+        margin: 0; min-height: 100vh; display: grid; place-items: center; padding: 16px;
+        font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
+        background: #f6f7f9; color: #14161a; line-height: 1.5;
+      }
+      main { max-width: 420px; text-align: center; }
+      h1 { font-size: 24px; margin: 0 0 8px; }
+      p { color: #5b6270; margin: 0 0 20px; }
+      a { color: #3b5bdb; font-weight: 600; }
+      @media (prefers-color-scheme: dark) {
+        body { background: #0f1115; color: #eceef2; }
+        p { color: #9aa1ad; }
+        a { color: #8299ff; }
+      }
+    </style>
+  </head>
+  <body>
+    <main>
+      <h1>Link não encontrado</h1>
+      <p>Esse link curto não existe ou sumiu quando o app foi publicado de novo.</p>
+      <a href="/">Encurtar um link</a>
+    </main>
+  </body>
+</html>
@@ -0,0 +1,122 @@
+import { readFileSync } from 'node:fs';
+
+import express from 'express';
+
+import { criarLink, ErroDeValidacao, FORMATO_CODIGO, listarLinks, registrarClique } from './links.js';
+
+const PORTA = Number(process.env.PORT) || 3000;
+// Variável de ambiente de exemplo: na Dado, ela se configura no painel do app.
+const MENSAGEM = process.env.MENSAGEM_BOAS_VINDAS || 'Defina a variável MENSAGEM_BOAS_VINDAS para trocar este texto.';
+const INICIO = new Date();
+
+const pacote = JSON.parse(readFileSync(new URL('./package.json', import.meta.url), 'utf8'));
+const lerPagina = (nome) => readFileSync(new URL(`./paginas/${nome}`, import.meta.url), 'utf8');
+
+const escaparHtml = (texto) =>
+  String(texto).replace(/[&<>"']/g, (c) => ({ '&': '&amp;', '<': '&lt;', '>': '&gt;', '"': '&quot;', "'": '&#39;' })[c]);
+
+const fusoBrasilia = { timeZone: 'America/Sao_Paulo' };
+const inicioFormatado = `${INICIO.toLocaleDateString('pt-BR', fusoBrasilia)} às ${INICIO.toLocaleTimeString('pt-BR', {
+  ...fusoBrasilia,
+  hour: '2-digit',
+  minute: '2-digit',
+})} (horário de Brasília)`;
+
+// A página é montada uma vez só: nada nela muda enquanto o processo vive.
+const paginaInicial = lerPagina('index.html')
+  .replace('{{RUNTIME}}', escaparHtml(`Express ${pacote.dependencies.express} · Node.js ${process.versions.node}`))
+  .replace('{{INICIO_ISO}}', INICIO.toISOString())
+  .replace('{{INICIO}}', escaparHtml(inicioFormatado))
+  .replace('{{MENSAGEM}}', escaparHtml(MENSAGEM));
+const paginaNaoEncontrada = lerPagina('nao-encontrado.html');
+
+// Freio simples contra abuso: no máximo 30 links novos a cada 10 minutos por IP.
+const LIMITE_POR_IP = 30;
+const JANELA_MS = 10 * 60 * 1000;
+const tentativas = new Map();
+
+function passouDoLimite(ip) {
+  const agora = Date.now();
+  if (tentativas.size > 10_000) tentativas.clear();
+  const atual = tentativas.get(ip);
+  if (!atual || atual.expiraEm <= agora) {
+    tentativas.set(ip, { total: 1, expiraEm: agora + JANELA_MS });
+    return false;
+  }
+  atual.total += 1;
+  return atual.total > LIMITE_POR_IP;
+}
+
+const app = express();
+app.disable('x-powered-by');
+// O app roda atrás de um proxy HTTPS: confia nos cabeçalhos X-Forwarded-*.
+app.set('trust proxy', true);
+
+const enderecoBase = (req) => `${req.protocol}://${req.get('host')}`;
+const paraJson = (link, req) => ({
+  codigo: link.codigo,
+  url: link.url,
+  curto: `${enderecoBase(req)}/${link.codigo}`,
+  cliques: link.cliques,
+  criadoEm: link.criadoEm,
+});
+
+// CORS aberto só na API: qualquer site (ou outro app seu) pode chamar /api/*.
+app.use('/api', (req, res, next) => {
+  res.set({
+    'Access-Control-Allow-Origin': '*',
+    'Access-Control-Allow-Methods': 'GET, POST, OPTIONS',
+    'Access-Control-Allow-Headers': 'Content-Type',
+  });
+  if (req.method === 'OPTIONS') return res.sendStatus(204);
+  next();
+});
+app.use('/api', express.json({ limit: '10kb' }));
+
+app.get('/', (req, res) => {
+  res.type('html').send(paginaInicial);
+});
+
+app.get('/api/links', (req, res) => {
+  res.set('Cache-Control', 'no-store');
+  res.json({ links: listarLinks().map((link) => paraJson(link, req)) });
+});
+
+app.post('/api/links', (req, res) => {
+  const ip = req.get('cf-connecting-ip') || req.ip;
+  if (passouDoLimite(ip)) {
+    return res.status(429).json({ erro: 'Muitos links em pouco tempo. Espere alguns minutos e tente de novo.' });
+  }
+  try {
+    const link = criarLink(req.body?.url);
+    res.status(201).json(paraJson(link, req));
+  } catch (erro) {
+    if (erro instanceof ErroDeValidacao) return res.status(400).json({ erro: erro.message });
+    throw erro;
+  }
+});
+
+// O redirecionamento é feito pelo servidor: GET /<código> → 302 para o link.
+app.get('/:codigo', (req, res, next) => {
+  if (!FORMATO_CODIGO.test(req.params.codigo)) return next();
+  const link = registrarClique(req.params.codigo);
+  if (!link) return res.status(404).type('html').send(paginaNaoEncontrada);
+  res.set('Cache-Control', 'no-store');
+  res.redirect(302, link.url);
+});
+
+app.use((req, res) => {
+  res.status(404).type('html').send(paginaNaoEncontrada);
+});
+
+// JSON malformado no corpo vira 400 com mensagem, não página de erro.
+app.use((erro, req, res, next) => {
+  if (erro.type === 'entity.parse.failed' || erro.type === 'entity.too.large') {
+    return res.status(400).json({ erro: 'Corpo inválido. Envie JSON no formato {"url": "https://..."}.' });
+  }
+  next(erro);
+});
+
+app.listen(PORTA, () => {
+  console.log(`Encurtador no ar em http://localhost:${PORTA}`);
+});