/**
* Desktop OAuth Callback Server
*
* Implements localhost callback server for desktop OAuth flows.
* Listens on random port on 127.0.0.1 for OAuth redirects.
*/
import { createServer, IncomingMessage, ServerResponse, Server } from 'http';
import { URL } from 'url';
import { AddressInfo } from 'net';
export interface OAuthCallbackResult {
code?: string;
state?: string;
error?: string;
error_description?: string;
}
/**
* Desktop OAuth callback server for PKCE flow
*/
export class DesktopOAuthServer {
private server: Server | null = null;
private port: number = 0;
private callbackPromise: Promise<OAuthCallbackResult> | null = null;
private callbackResolve: ((result: OAuthCallbackResult) => void) | null = null;
private callbackReject: ((error: Error) => void) | null = null;
/**
* Start the OAuth callback server on a random port
*/
async start(): Promise<number> {
if (this.server) {
throw new Error('OAuth callback server is already running');
}
return new Promise((resolve, reject) => {
this.server = createServer(this.handleRequest.bind(this));
this.server.on('error', (error) => {
console.error('OAuth callback server error:', error);
reject(error);
});
// Listen on random port on 127.0.0.1 (localhost)
this.server.listen(0, '127.0.0.1', () => {
const address = this.server!.address() as AddressInfo;
this.port = address.port;
console.error(`š Desktop OAuth server listening on http://127.0.0.1:${this.port}`);
resolve(this.port);
});
});
}
/**
* Stop the OAuth callback server
*/
async stop(): Promise<void> {
if (!this.server) {
return;
}
return new Promise((resolve, reject) => {
this.server!.close((error) => {
if (error) {
console.error('Error stopping OAuth callback server:', error);
reject(error);
} else {
console.error('ā
Desktop OAuth server stopped');
this.server = null;
this.port = 0;
resolve();
}
});
});
}
/**
* Get the callback URL for this server
*/
getCallbackUrl(): string {
if (!this.server || this.port === 0) {
throw new Error('OAuth callback server is not running');
}
return `http://127.0.0.1:${this.port}/callback`;
}
/**
* Get the server port
*/
getPort(): number {
return this.port;
}
/**
* Check if server is running
*/
isRunning(): boolean {
return this.server !== null && this.port !== 0;
}
/**
* Wait for OAuth callback
*/
async waitForCallback(expectedState?: string, timeoutMs: number = 300000): Promise<OAuthCallbackResult> {
if (this.callbackPromise) {
throw new Error('Already waiting for OAuth callback');
}
this.callbackPromise = new Promise((resolve, reject) => {
this.callbackResolve = resolve;
this.callbackReject = reject;
// Set timeout
setTimeout(() => {
if (this.callbackReject) {
this.callbackReject(new Error('OAuth callback timeout after 5 minutes'));
this.callbackPromise = null;
this.callbackResolve = null;
this.callbackReject = null;
}
}, timeoutMs);
});
try {
const result = await this.callbackPromise;
// Validate state parameter if provided
if (expectedState && result.state !== expectedState) {
throw new Error(`OAuth state mismatch. Expected: ${expectedState}, Received: ${result.state}`);
}
return result;
} finally {
this.callbackPromise = null;
this.callbackResolve = null;
this.callbackReject = null;
}
}
/**
* Handle incoming HTTP requests
*/
private handleRequest(req: IncomingMessage, res: ServerResponse): void {
const url = new URL(req.url || '', `http://127.0.0.1:${this.port}`);
console.error(`š„ OAuth callback request: ${req.method} ${url.pathname}`);
if (url.pathname === '/callback') {
this.handleOAuthCallback(url, res);
} else if (url.pathname === '/health') {
this.handleHealthCheck(res);
} else {
this.handleNotFound(res);
}
}
/**
* Handle OAuth callback
*/
private handleOAuthCallback(url: URL, res: ServerResponse): void {
const params = url.searchParams;
const code = params.get('code');
const state = params.get('state');
const error = params.get('error');
const errorDescription = params.get('error_description');
console.error(`š OAuth callback received:`, {
hasCode: !!code,
hasState: !!state,
hasError: !!error,
state: state?.substring(0, 20) + '...'
});
// Send response to browser
if (error) {
this.sendErrorResponse(res, error, errorDescription);
} else if (code) {
this.sendSuccessResponse(res);
} else {
this.sendErrorResponse(res, 'invalid_request', 'Missing authorization code');
}
// Resolve callback promise
if (this.callbackResolve) {
this.callbackResolve({
code: code || undefined,
state: state || undefined,
error: error || undefined,
error_description: errorDescription || undefined
});
}
}
/**
* Handle health check
*/
private handleHealthCheck(res: ServerResponse): void {
res.writeHead(200, { 'Content-Type': 'application/json' });
res.end(JSON.stringify({
status: 'ok',
server: 'MCP Gas Desktop OAuth',
port: this.port
}));
}
/**
* Handle 404 not found
*/
private handleNotFound(res: ServerResponse): void {
res.writeHead(404, { 'Content-Type': 'text/html' });
res.end(`
<!DOCTYPE html>
<html>
<head><title>OAuth Server - Not Found</title></head>
<body>
<h1>404 - Not Found</h1>
<p>OAuth callback server is running on port ${this.port}</p>
<p>Valid endpoints: /callback, /health</p>
</body>
</html>
`);
}
/**
* Send success response to browser
*/
private sendSuccessResponse(res: ServerResponse): void {
res.writeHead(200, { 'Content-Type': 'text/html' });
res.end(`
<!DOCTYPE html>
<html>
<head>
<title>OAuth Success</title>
<style>
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; margin: 0; padding: 40px; background: #f5f5f5; }
.container { max-width: 500px; margin: 0 auto; background: white; padding: 40px; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); text-align: center; }
.success-icon { font-size: 48px; color: #4CAF50; margin-bottom: 20px; }
h1 { color: #333; margin-bottom: 10px; }
p { color: #666; margin-bottom: 20px; }
</style>
</head>
<body>
<div class="container">
<div class="success-icon">ā
</div>
<h1>Authentication Successful</h1>
<p>You have successfully authenticated with Google Apps Script.</p>
<p>You can now close this browser tab and return to your application.</p>
</div>
<script>
// Auto-close tab after 3 seconds
setTimeout(() => {
window.close();
}, 3000);
</script>
</body>
</html>
`);
}
/**
* Send error response to browser
*/
private sendErrorResponse(res: ServerResponse, error: string, description?: string | null): void {
res.writeHead(400, { 'Content-Type': 'text/html' });
res.end(`
<!DOCTYPE html>
<html>
<head>
<title>OAuth Error</title>
<style>
body { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; margin: 0; padding: 40px; background: #f5f5f5; }
.container { max-width: 500px; margin: 0 auto; background: white; padding: 40px; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.1); text-align: center; }
.error-icon { font-size: 48px; color: #f44336; margin-bottom: 20px; }
h1 { color: #333; margin-bottom: 10px; }
p { color: #666; margin-bottom: 20px; }
.error-code { background: #f5f5f5; padding: 10px; border-radius: 4px; font-family: monospace; }
</style>
</head>
<body>
<div class="container">
<div class="error-icon">ā</div>
<h1>Authentication Failed</h1>
<p>There was a problem with the authentication process.</p>
<div class="error-code">
<strong>Error:</strong> ${error}<br>
${description ? `<strong>Description:</strong> ${description}` : ''}
</div>
<p>Please try again or check your configuration.</p>
</div>
</body>
</html>
`);
}
}
