Error occurred while trying to proxy: localhost:3000/

[siddhsql]

Hello,

I am trying to use this library to forward requests to a Svelte app. I have this configuration:

app.use(
  '/',
  createProxyMiddleware({
    target: 'http://localhost:5173/',
    changeOrigin: true,
  }),
);

app.listen(3000);

I run my Svelte app using:

npm run dev -- --host 0.0.0.0

which outputs:

VITE v5.2.12  ready in 483 ms

  ➜  Local:   http://localhost:5173/
  ➜  Network: http://192.168.x.x:5173/
  ➜  press h + enter to show help

but when I try to make a curl request:

curl http://localhost:3000

I get:

Error occurred while trying to proxy: localhost:3000/%

curl -I http://localhost:3000/
HTTP/1.1 504 Gateway Timeout
X-Powered-By: Express
Date: Wed, 12 Jun 2024 22:24:59 GMT
Connection: keep-alive
Keep-Alive: timeout=5

it complains of a timeout but the error happens almost instantaneously.

Making the request directly works:

curl http://localhost:5173

Also if I run the app like:

npm run dev

instead of

npm run dev -- --host 0.0.0.0

then also it works! what is going on here? how can I run the app with --host 0.0.0.0 and still proxy requests to it?

[siddhsql]

╰─➤  lsof -i :5173
COMMAND   PID     USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
node    23073 xxx   36u  IPv4 0x8exxxxxxxxxxxx1      0t0  TCP *:5173 (LISTEN)

[siddhsql]

making some more notes. I added an event handler to the error event and now see this:

Error: connect ECONNREFUSED ::1:5173
    at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1555:16) {
  errno: -61,
  code: 'ECONNREFUSED',
  syscall: 'connect',
  address: '::1',
  port: 5173
}

also lsof shows following:

╰─➤  lsof -i :5173
COMMAND   PID     USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
node    24570 xxx   31u  IPv6 0x8xxxxxxxxxx9      0t0  TCP localhost:5173 (LISTEN)

and my /etc/hosts:

─➤  cat /etc/hosts
##
# Host Database
#
# localhost is used to configure the loopback interface
# when the system is booting.  Do not change this entry.
##
127.0.0.1	localhost
255.255.255.255	broadcasthost
::1             localhost

so it ought to work.