How to call https through Fiddler Classic from nodejs?

[David]

I need Fiddler to capture my call from nodejs. 

I call https://domain from nodejs like this

  import { ProxyAgent, fetch } from 'undici';
  const dispatcher = new ProxyAgent('http://127.0.0.1:8888' )
   var r2 = await fetch('https://domain', {
	method: 'POST',
	dispatcher,
	headers: {	
                 ...}
	  },
    body:  ...
  }
  );
  var r2data = await r2.json();

I can do the above call to http://domain, but when I changed to https://domain, I got the below error, any idea how do I handle this? thanks

  [cause]: Error: unable to verify the first certificate
      at TLSSocket.onConnectSecure (node:_tls_wrap:1674:34)
      at TLSSocket.emit (node:events:519:28)
      at TLSSocket._finishInit (node:_tls_wrap:1085:8)
      at ssl.onhandshakedone (node:_tls_wrap:871:12)
      at TLSWrap.callbackTrampoline (node:internal/async_hooks:130:17) {
    code: 'UNABLE_TO_VERIFY_LEAF_SIGNATURE'

[Nick Iliev]

Hello David,

 

You might consider the methods outlined here (even though the article is for Fiddler Everywhere, the process remains the same): https://www.telerik.com/fiddler/fiddler-everywhere/documentation/capture-traffic/advanced-capturing-options/capturing-nodejs-traffic. 

You can set NODE_TLS_REJECT_UNAUTHORIZED to 0, but be aware that this poses a significant security risk, so use it only for testing and revert afterward.

Alternatively, you could export the Fiddler CA certificate as PEM and set it using NODE_EXTRA_CA_CERTS. Fiddler Classic only exports in CRT format, so you'll need to manually convert it to PEM, for example, with:

openssl x509 -inform der -in certificate.cer -out certificate.pem

Fiddler Everywhere offers an automated option to export directly to PEM.

 

Regards,
Nick Iliev
Progress Telerik