How to get the size of the response?

[lazydefi1]

In a middleware, is there a way to get the size of the response ctx.res sent to the client?

[mattreid1]

There isn't a way natively to do it that I know of. Bao uses the Bun Response type so you would have to use that to calculate it. Off the top of my head, I'd probably enumerate the headers to calculate their length, add the response length (e.g. array buffer, text, etc.), and then add the status line length. I might be missing something else but that's the gist of it. If that doesn't work, you could try using a reverse proxy to read its exact length?

[lazydefi1]

I see what you mean but because the server is computing the Content-length header somewhere, I thought it might be possible to get this header as well.

Here is my attempt:

app.after((ctx: Context) => {
  console.log('➡️', ctx.req.method, ctx.res.status, ctx.req.url, ctx.res.headers.get('Content-length'), 'bytes');
  return ctx;
});

However, here is the result:

➡️ GET 200 http://0.0.0.0:3000/ null bytes

It is strange because the status is accessible but not the computed header...