/**
* OAuth Callback Endpoint
*/
import { generateRandomString } from '../helpers.js';
import { pendingAuthorizations, codeToAuthorization } from '../storage.js';
/**
* GET /callback
*
* Handles callback from Google OAuth.
* Receives authorization code from Google, generates our own code,
* and redirects to ChatGPT's callback.
*
* Query params from Google:
* - code: Google's authorization code
* - state: The state we sent to Google (to find pending auth)
*/
export function handleCallback(req: Request): Response {
const url = new URL(req.url);
const params = url.searchParams;
console.error('[OAuth] ════════════════════════════════════════');
console.error('[OAuth] /callback from Google received');
console.error('[OAuth] All query params:');
for (const [key, value] of params.entries()) {
if (key === 'code') {
console.error(`[OAuth] ${key}: ${value.substring(0, 20)}...`);
} else {
console.error(`[OAuth] ${key}: ${value}`);
}
}
const googleCode = params.get('code');
const state = params.get('state');
const error = params.get('error');
// Handle errors from Google
if (error) {
console.error(`[OAuth] ✗ Google returned error: ${error}`);
return new Response(`Authorization failed: ${error}`, { status: 400 });
}
if (!googleCode || !state) {
console.error('[OAuth] ✗ Missing code or state from Google');
return new Response('Missing code or state', { status: 400 });
}
// Find pending authorization
const pendingAuth = pendingAuthorizations.get(state);
if (!pendingAuth) {
console.error(`[OAuth] ✗ No pending authorization for state: ${state}`);
console.error(
`[OAuth] Available states: ${Array.from(pendingAuthorizations.keys()).join(', ') || 'none'}`
);
return new Response('Invalid or expired state', { status: 400 });
}
console.error(`[OAuth] ✓ Found pending auth for state: ${state}`);
// Store Google code and generate our own code for ChatGPT
const ourCode = generateRandomString(32);
pendingAuth.googleCode = googleCode;
pendingAuth.ourCode = ourCode;
// Store mapping from our code to authorization
codeToAuthorization.set(ourCode, pendingAuth);
// Build redirect URL to ChatGPT
const redirectUrl = new URL(pendingAuth.chatgptRedirectUri);
redirectUrl.searchParams.set('code', ourCode);
redirectUrl.searchParams.set('state', pendingAuth.chatgptState);
console.error(`[OAuth] Redirecting to ChatGPT: ${redirectUrl.toString()}`);
// Redirect to ChatGPT
return new Response(null, {
status: 302,
headers: {
Location: redirectUrl.toString(),
},
});
}
