feat: WHOIS API 서버 초기 구현

- Vercel Serverless Functions 기반
- TCP 포트 43 직접 연결로 모든 TLD 지원
- TLD별 WHOIS 서버 매핑 (~50개)
- 리퍼럴 서버 자동 추적
- JSON 응답 (raw WHOIS 포함)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.gitignore

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+node_modules/
+.vercel/
+dist/
+*.log
+.env
+.env.local
+.vercel

api/whois/[domain].ts

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+import { createConnection } from 'net';
+import type { VercelRequest, VercelResponse } from '@vercel/node';
+
+// TLD to WHOIS server mapping
+const WHOIS_SERVERS: Record<string, string> = {
+  // Generic TLDs
+  com: 'whois.verisign-grs.com',
+  net: 'whois.verisign-grs.com',
+  org: 'whois.pir.org',
+  info: 'whois.afilias.net',
+  biz: 'whois.biz',
+
+  // Popular new gTLDs
+  io: 'whois.nic.io',
+  co: 'whois.registry.co',
+  me: 'whois.nic.me',
+  tv: 'whois.nic.tv',
+  cc: 'whois.nic.cc',
+  app: 'whois.nic.google',
+  dev: 'whois.nic.google',
+  xyz: 'whois.nic.xyz',
+  online: 'whois.nic.online',
+  site: 'whois.nic.site',
+  tech: 'whois.nic.tech',
+  shop: 'whois.nic.shop',
+  blog: 'whois.nic.blog',
+  club: 'whois.nic.club',
+  live: 'whois.nic.live',
+  cloud: 'whois.nic.cloud',
+
+  // Country Code TLDs
+  kr: 'whois.kr',
+  jp: 'whois.jprs.jp',
+  cn: 'whois.cnnic.cn',
+  uk: 'whois.nic.uk',
+  de: 'whois.denic.de',
+  fr: 'whois.nic.fr',
+  it: 'whois.nic.it',
+  es: 'whois.nic.es',
+  nl: 'whois.domain-registry.nl',
+  ru: 'whois.tcinet.ru',
+  ca: 'whois.cira.ca',
+  in: 'whois.registry.in',
+  mx: 'whois.mx',
+  cv: 'whois.nic.cv',
+  au: 'whois.auda.org.au',
+  br: 'whois.registro.br',
+
+  // ccSLDs
+  'it.com': 'whois.centralnic.com',
+  'uk.com': 'whois.centralnic.com',
+  'us.com': 'whois.centralnic.com',
+  'eu.com': 'whois.centralnic.com',
+  'co.kr': 'whois.kr',
+  'or.kr': 'whois.kr',
+  'co.uk': 'whois.nic.uk',
+  'org.uk': 'whois.nic.uk',
+  'com.au': 'whois.auda.org.au',
+};
+
+function getWhoisServer(domain: string): string {
+  const parts = domain.toLowerCase().split('.');
+
+  // Check ccSLD first (e.g., co.kr, it.com)
+  if (parts.length >= 3) {
+    const ccSLD = parts.slice(-2).join('.');
+    if (WHOIS_SERVERS[ccSLD]) {
+      return WHOIS_SERVERS[ccSLD];
+    }
+  }
+
+  // Then check TLD
+  const tld = parts[parts.length - 1];
+  return WHOIS_SERVERS[tld] || 'whois.iana.org';
+}
+
+function queryWhois(server: string, domain: string): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const chunks: Buffer[] = [];
+
+    // Special query formats for some servers
+    let query = domain;
+    if (server.includes('verisign')) {
+      query = '=' + domain;
+    } else if (server.includes('denic.de')) {
+      query = '-T dn,ace ' + domain;
+    } else if (server.includes('jprs.jp')) {
+      query = domain + '/e';
+    }
+
+    const socket = createConnection(43, server, () => {
+      socket.write(query + '\r\n');
+    });
+
+    socket.setTimeout(15000);
+
+    socket.on('data', (data) => {
+      chunks.push(data);
+    });
+
+    socket.on('end', () => {
+      resolve(Buffer.concat(chunks).toString('utf-8'));
+    });
+
+    socket.on('timeout', () => {
+      socket.destroy();
+      reject(new Error('Connection timeout'));
+    });
+
+    socket.on('error', (err) => {
+      reject(err);
+    });
+  });
+}
+
+function extractReferral(raw: string): string | null {
+  const patterns = [
+    /Registrar WHOIS Server:\s*(.+)/i,
+    /Whois Server:\s*(.+)/i,
+    /ReferralServer:\s*whois:\/\/(.+)/i,
+    /refer:\s*(.+)/i,
+  ];
+
+  for (const pattern of patterns) {
+    const match = raw.match(pattern);
+    if (match && match[1]) {
+      const server = match[1].trim().replace('whois://', '');
+      if (server && !server.includes(' ')) {
+        return server;
+      }
+    }
+  }
+  return null;
+}
+
+function checkAvailability(raw: string): boolean {
+  const availablePatterns = [
+    'no match for',
+    'not found',
+    'no data found',
+    'domain not found',
+    'no entries found',
+    'status: available',
+    'the queried object does not exist',
+    'is available for registration',
+    'this domain name has not been registered',
+  ];
+
+  const rawLower = raw.toLowerCase();
+  return availablePatterns.some(p => rawLower.includes(p));
+}
+
+export default async function handler(req: VercelRequest, res: VercelResponse) {
+  // CORS
+  res.setHeader('Access-Control-Allow-Origin', '*');
+  res.setHeader('Access-Control-Allow-Methods', 'GET, OPTIONS');
+  res.setHeader('Access-Control-Allow-Headers', 'X-API-Key, Content-Type');
+
+  if (req.method === 'OPTIONS') {
+    return res.status(200).end();
+  }
+
+  // API Key check (optional)
+  const apiKey = process.env.API_KEY;
+  if (apiKey && req.headers['x-api-key'] !== apiKey) {
+    return res.status(401).json({ error: 'Invalid API key' });
+  }
+
+  const { domain } = req.query;
+
+  if (!domain || typeof domain !== 'string') {
+    return res.status(400).json({ error: 'Domain parameter required' });
+  }
+
+  const domainName = domain.toLowerCase().trim();
+  const startTime = Date.now();
+
+  try {
+    const whoisServer = getWhoisServer(domainName);
+    let raw = await queryWhois(whoisServer, domainName);
+    let usedServer = whoisServer;
+
+    // Follow referral if exists
+    const referral = extractReferral(raw);
+    if (referral && referral !== whoisServer) {
+      try {
+        const referralRaw = await queryWhois(referral, domainName);
+        if (referralRaw.length > raw.length / 2) {
+          raw = referralRaw;
+          usedServer = referral;
+        }
+      } catch {
+        // Keep original response if referral fails
+      }
+    }
+
+    const available = checkAvailability(raw);
+    const queryTime = Date.now() - startTime;
+
+    return res.status(200).json({
+      domain: domainName,
+      available,
+      whois_server: usedServer,
+      raw,
+      query_time_ms: queryTime,
+    });
+
+  } catch (error) {
+    const queryTime = Date.now() - startTime;
+    return res.status(500).json({
+      domain: domainName,
+      error: error instanceof Error ? error.message : 'Unknown error',
+      query_time_ms: queryTime,
+    });
+  }
+}

package.json

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+{
+  "name": "whois-api",
+  "version": "1.0.0",
+  "private": true,
+  "scripts": {
+    "dev": "vercel dev",
+    "deploy": "vercel --prod"
+  },
+  "dependencies": {},
+  "devDependencies": {
+    "@types/node": "^20.0.0",
+    "typescript": "^5.0.0",
+    "vercel": "^37.0.0"
+  }
+}

tsconfig.json

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+{
+  "compilerOptions": {
+    "target": "ES2020",
+    "module": "commonjs",
+    "strict": true,
+    "esModuleInterop": true,
+    "skipLibCheck": true,
+    "forceConsistentCasingInFileNames": true,
+    "outDir": "./dist",
+    "rootDir": "."
+  },
+  "include": ["api/**/*"],
+  "exclude": ["node_modules"]
+}

vercel.json

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+{
+  "version": 2,
+  "functions": {
+    "api/**/*.ts": {
+      "maxDuration": 30
+    }
+  }
+}