[examples/with-firebase-hosting] Gateway error on POST requests

[masonlouchart]

Bug report

I get a “502 Gateway” error from NextJs app hosted on Firebase for POST requests.

Describe the bug

I started to build an API using NextJs framework. I want it to be hosted on Firebase (Hosting and Functions). Everything is working as long as I send only GET requests. When I send a POST request I receive a "502 Bad Gateway" error.

To Reproduce

Download and deploy the example provided.

• create a new project on Firebase console
• install the "with Firebase hosting" example
• change the project name in the .firebaserc (line 3) file
• create a folder "api" under the folder "pages"
• create a file "hello.js" under the folder "api" and add the following snippet

export default async (req, res) => {
  const {
    body,
    method
  } = req;

  console.log("method :>> ", method);
  console.log("body :>> ", body);

  switch (method) {
  case "POST":
    res.status(200).end(`Method ${method} supported!`);
    break;
  default:
    res.setHeader("Allow", ["POST"]);
    res.status(405).end(`Method ${method} Not Allowed`);
  }
};

• deploy the app
• send a GET request to "https://[project-name].web.app/api/hello" and see it works
• send a POST request to "https://[project-name].web.app/api/hello" and see it does not work

Expected behavior

The POST request should be answered with 200 - Method POST is supported!.

Screenshots

Additional context

https://stackoverflow.com/questions/63968953/why-do-i-get-a-502-gateway-error-from-nextjs-app-hosted-on-firebase-for-post-r#comment113117374_63968953