HonoH
Hono•2y ago
nullfox

Hono CORS lambda duplicate headers

I'm using Hono with Lambda and managing CORS myself instead of using AWS API Gateway CORS configuration.

My code looks like

import { Hono, Context as HonoContext } from 'hono';
import { cors as corsMiddleware } from 'hono/cors';

import { upsertInvoice } from './embed/routes/v1/upsertInvoice.js';

const routes = [
    {
        method: ['POST'],
        path: '/v1/invoices',
        handler: upsertInvoice,
    },
];

export const server = new Hono();

const cors = corsMiddleware({
    allowMethods: ['GET', 'POST', 'OPTIONS'],
    allowHeaders: [
        'Content-Type',
        'X-Amz-Date',
        'Authorization',
        'X-Api-Key',
        'X-Amz-Security-Token',
    ],
    origin: '*',
});

routes.forEach((route) => {
    // Register the actual route
    server.on(route.method, route.path, route.handler);

    // Register cors for the route
    server.on(['OPTIONS'], route.path, cors);
});


When I deploy this to AWS and do an OPTIONS request to that endpoint, I'm getting duplicate CORS headers like:

< date: Wed, 31 Jul 2024 17:38:25 GMT
< access-control-allow-headers: Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token
< access-control-allow-headers: Content-Type,X-Amz-Date,Authorization,X-Api-Key,X-Amz-Security-Token
< access-control-allow-methods: GET,POST,OPTIONS
< access-control-allow-methods: GET,POST,OPTIONS
< access-control-allow-origin: *
< access-control-allow-origin: *
< vary: Access-Control-Request-Headers
< vary: Access-Control-Request-Headers
< apigw-requestid: byd2yghRIAMEPdA=


I'm unclear on what I'm doing wrong that wouldo generate these dupe headers that breaks CORS
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