Connect via WSS to Polkadot Full Noder running on local network failed

Question

I have setup a Full Node running at a local server at 192.168.2.254. I'm just trying to make a simple script which is basically subscribe to new heads on the blockchain.

const { ApiPromise, WsProvider } = require('@polkadot/api');

async function main () {
  const wsProvider = new WsProvider('wss://192.168.2.254:9944');
  const api = await ApiPromise.create({ provider: wsProvider });

  let count = 0;

  const unsubscribe = await api.rpc.chain.subscribeNewHeads((header) => {
    console.log(`Chain is at block: #${header.number}`);

    if (++count === 256) {
      unsubscribe();
      process.exit(0);
    }
  });
}

main().catch(console.error);

On the server, I've also setup nginx with a self signed ssl certificate as suggested by Polkadot wiki. Here is the block config:

server {
        server_name 192.168.2.254

        root /var/www/html;
        index index.html;

        location / {
                try_files $uri $uri/ =404;

                proxy_pass http://localhost:9944;
                proxy_set_header X-Real-IP $remote_addr;
                proxy_set_header Host $host;
                proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;

                proxy_http_version 1.1;
                proxy_set_header Upgrade $http_upgrade;
                proxy_set_header Connection "upgrade";
        }

        listen [::]:443 ssl ipv6only=on;
        listen 443 ssl;
        ssl_certificate /etc/ssl/certs/nginx-selfsigned.crt;
        ssl_certificate_key /etc/ssl/private/nginx-selfsigned.key;

        ssl_session_cache shared:cache_nginx_SSL:1m;
        ssl_session_timeout 1440m;

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        ssl_prefer_server_ciphers on;

        ssl_ciphers "ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-AES128-SHA256:ECDHE-RSA-AES128-SHA256:ECDHE-ECDSA-AES128-SHA:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA:ECDHE-ECDSA-AES256-SHA384:ECDHE-ECDSA-AES256-SHA:ECDHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA256:DHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES256-SHA:ECDHE-ECDSA-DES-CBC3-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES128-GCM-SHA256:AES256-GCM-SHA384:AES128-SHA256:AES256-SHA256:AES128-SHA:AES256-SHA:DES-CBC3-SHA:!DSS";

        ssl_dhparam /etc/ssl/certs/dhparam.pem;
}

If I run the script directly on the server, with no provider configured (it will use ws://127.0.0.1:9944) by default, there is no problem. But when I run it on my local machine to point to wss://192.168.2.254:9944, the output is connection failed with code 1006:

node listenToBlock.js ─╯

2020-09-10 14:19:29          API-WS: disconnected from ws://192.168.2.254:9944 code: '1006' reason: 'connection failed'
_Event {
  type: 'error',
  isTrusted: false,
  _yaeti: true,
  target:
   W3CWebSocket {
     _listeners: {},
     addEventListener: [Function: _addEventListener],
     removeEventListener: [Function: _removeEventListener],
     dispatchEvent: [Function: _dispatchEvent],
     _url: 'ws://192.168.2.254:9944',
     _readyState: 3,
     _protocol: undefined,
     _extensions: '',
     _bufferedAmount: 0,
     _binaryType: 'arraybuffer',
     _connection: undefined,
     _client:
      WebSocketClient {
        _events: [Object: null prototype] {},
        _eventsCount: 0,
        _maxListeners: undefined,
        config: [Object],
        _req: null,
        protocols: [],
        origin: undefined,
        url: [Url],
        secure: false,
        base64nonce: 'cUJFFas2Ec3aN5YlHSxehg==' },
     onclose: [Function: value],
     onerror: [Function: value],
     onmessage: [Function: value],
     onopen: [Function: value] },
  cancelable: true,
  stopImmediatePropagation: [Function] }
2020-09-10 14:19:30          API-WS: disconnected from ws://192.168.2.254:9944 code: '1006' reason: 'connection failed'
2020-09-10 14:19:31          API-WS: disconnected from ws://192.168.2.254:9944 code: '1006' reason: 'connection failed'

I also tried to use https://polkadot.js.org/apps/#/explorer with a development endpoint set to wss://192.168.2.254 successfully after accepting the unverified certificate in the browser.

My best guess is connection from the script on my local machine needs to accept the unverified certificates too, but I cannot find any documents to help with that. I appreciate any help from you!

Answer 1

At the endpoint url, providing port 9944 is wrong because wss always default to use port 443.

I solved this problem by running the script with

NODE_TLS_REJECT_UNAUTHORIZED=0 node listenToBlock.js

Seems like an OK workaround for dev environment.