Websocket authorzation handler - return something that isn't `500`?

$connect の WebSocket 設定と authHandler の戻り値から始め、それらを API Gateway の authorizer コントラクトおよび観測された 500 レスポンスと比較します。この例でサポートされるエラーステータスと TypeScript のハンドラー型が確定し、secret を含まないリクエストに対する再現可能なチェックがあれば完了です。

Question / help needed

I'm trying to get authorization working before connecting to websockets, which works, but I'm struggling to return an error message that isn't 500.

I've managed to make an auth handler, like so:

    connectHandler: {
      handler: 'handler.connectHandler',
      events: [
        {
          "websocket": {
            route: "$connect",
            authorizer: {
              name: "authHandler",
              identitySource: [
                // No identity source, leave it up to the handler
              ],
            },
          },
        },
      ],
      environment: {
        // ..
      },
    },

Any my authHandler:

export const authHandler = async (event, _context) => {
  console.log('🔑 Auth request received', event.requestContext)

  const token = event.headers.Authorization ?? event.queryStringParameters.Authorization;
  console.log('Token:', token)

  if (token !== 'secret') {
    return {
      statusCode: 401,
    }
  }

  return {
    "principalId": "user",
    "policyDocument": {
      "Version": "2012-10-17",
      "Statement": [
        {
          "Action": "execute-api:Invoke",
          "Effect": "Allow",
          "Resource": event.methodArn
        }
      ]
    }
  };
}

Questions:

• what should I return in case of an error? Any request to my websocket-server that doesn't have the secret header/querystring returns 500 right now, and I'd prefer it to return a 4xx status code.

• what is the correct type for the authorization handler? I'm using APIGatewayProxyHandler on the other fn handlers which gives me nice inline errors.

  How my other handlers look like, which gives me pleasant TypeScript-errors when I do something wrong

  ```ts

  export const connectHandler: APIGatewayProxyHandler = async (event, _context) => {
  const connectionId = event.requestContext.connectionId!

  console.log('➕ Adding connection ', connectionId)

  await client.query('INSERT INTO "public"."Connection"("id") VALUES($1) RETURNING *', [connectionId])
  return {
  statusCode: 200,
  body: '',
  };
  }

  </details>