#!/usr/bin/env node
/**
* Gmail OAuth Authentication Script
*
* Run this once to authenticate with Google and store tokens locally.
* Usage: npm run auth
*/
import { google } from "googleapis";
import * as fs from "fs";
import * as path from "path";
import * as http from "http";
import * as url from "url";
const CONFIG_DIR = process.env.GMAIL_CONFIG_DIR || path.join(process.env.HOME || "", ".mcp-gmail");
const TOKEN_PATH = path.join(CONFIG_DIR, "token.json");
const CREDENTIALS_PATH = process.env.GMAIL_CREDENTIALS_PATH || path.join(CONFIG_DIR, "credentials.json");
const SCOPES = [
"https://www.googleapis.com/auth/gmail.readonly",
"https://www.googleapis.com/auth/gmail.send",
"https://www.googleapis.com/auth/gmail.modify",
];
async function authenticate() {
// Ensure config directory exists
if (!fs.existsSync(CONFIG_DIR)) {
fs.mkdirSync(CONFIG_DIR, { recursive: true });
}
// Check for credentials
if (!fs.existsSync(CREDENTIALS_PATH)) {
console.error(`
╔══════════════════════════════════════════════════════════════════╗
║ Credentials file not found! ║
╠══════════════════════════════════════════════════════════════════╣
║ Please download your OAuth credentials from Google Cloud ║
║ Console and save them to: ║
║ ║
║ ${CREDENTIALS_PATH.padEnd(62)}║
║ ║
║ Steps: ║
║ 1. Go to console.cloud.google.com ║
║ 2. APIs & Services → Credentials ║
║ 3. Download OAuth 2.0 Client ID JSON ║
║ 4. Save as credentials.json in the path above ║
╚══════════════════════════════════════════════════════════════════╝
`);
process.exit(1);
}
const credentials = JSON.parse(fs.readFileSync(CREDENTIALS_PATH, "utf-8"));
const { client_id, client_secret } = credentials.installed || credentials.web;
// Use localhost redirect for OAuth
const redirectUri = "http://localhost:3333/oauth2callback";
const oauth2Client = new google.auth.OAuth2(client_id, client_secret, redirectUri);
// Check if we already have a token
if (fs.existsSync(TOKEN_PATH)) {
console.log("Token already exists. Do you want to re-authenticate? (y/n)");
const readline = await import("readline");
const rl = readline.createInterface({ input: process.stdin, output: process.stdout });
const answer = await new Promise<string>((resolve) => {
rl.question("> ", resolve);
});
rl.close();
if (answer.toLowerCase() !== "y") {
console.log("Keeping existing token.");
process.exit(0);
}
}
// Generate auth URL
const authUrl = oauth2Client.generateAuthUrl({
access_type: "offline",
scope: SCOPES,
prompt: "consent",
});
console.log(`
╔══════════════════════════════════════════════════════════════════╗
║ Gmail OAuth Authentication ║
╠══════════════════════════════════════════════════════════════════╣
║ Opening browser for Google authentication... ║
║ If it doesn't open, copy this URL manually: ║
╚══════════════════════════════════════════════════════════════════╝
${authUrl}
Waiting for authentication callback...
`);
// Open browser
const open = (await import("open")).default;
await open(authUrl);
// Start local server to receive callback
return new Promise<void>((resolve, reject) => {
const server = http.createServer(async (req, res) => {
try {
const reqUrl = url.parse(req.url || "", true);
if (reqUrl.pathname === "/oauth2callback") {
const code = reqUrl.query.code as string;
if (!code) {
res.writeHead(400);
res.end("No authorization code received");
return;
}
// Exchange code for tokens
const { tokens } = await oauth2Client.getToken(code);
oauth2Client.setCredentials(tokens);
// Save token
fs.writeFileSync(TOKEN_PATH, JSON.stringify(tokens, null, 2));
res.writeHead(200, { "Content-Type": "text/html" });
res.end(`
<!DOCTYPE html>
<html>
<head><title>Authentication Successful</title></head>
<body style="font-family: system-ui; display: flex; justify-content: center; align-items: center; height: 100vh; margin: 0;">
<div style="text-align: center;">
<h1 style="color: #22c55e;">✓ Authentication Successful!</h1>
<p>You can close this window and return to the terminal.</p>
</div>
</body>
</html>
`);
console.log(`
╔══════════════════════════════════════════════════════════════════╗
║ ✓ Authentication successful! ║
╠══════════════════════════════════════════════════════════════════╣
║ Token saved to: ${TOKEN_PATH.substring(0, 44).padEnd(44)}║
║ ║
║ The Gmail MCP server is now ready to use. ║
║ Restart Claude Code to load the new server. ║
╚══════════════════════════════════════════════════════════════════╝
`);
server.close();
resolve();
}
} catch (error) {
console.error("Authentication error:", error);
res.writeHead(500);
res.end("Authentication failed");
server.close();
reject(error);
}
});
server.listen(3333, () => {
console.log("OAuth callback server listening on http://localhost:3333");
});
// Timeout after 5 minutes
setTimeout(() => {
server.close();
reject(new Error("Authentication timed out after 5 minutes"));
}, 5 * 60 * 1000);
});
}
authenticate().catch((error) => {
console.error("Authentication failed:", error.message);
process.exit(1);
});
