how to monitor the network on node.js similar to chrome/firefox developer tools?

Question

When developing client side javascript applications, the developer network panel is invaluable for debugging network issues:

How does a developer creating a NodeJS application monitor the network traffic from the nodejs application to a http/https server? For example how to debug the following network traffic?

var http = require('http');
var req = http.request ...
req.write ...
req.send()

My code is making a call to a third party https server, so I am unable to use wireshark or similar packet sniffing tools.

For more information, the problem I am trying to investigate is here.

EDIT:

Here are similar questions asking how to do the same thing in other languages:

• PYTHON: How can I see the entire HTTP request that's being sent by my Python application?
• JAVA: How to enable logging for apache commons HttpClient on Android

Answer 1

I know it's not pretty, but you could always output the content of the response headers on the console inside your request call:

var req = https.request(options, function(res) {
    console.log("statusCode: ", res.statusCode);
    console.log("headers: ", res.headers);

    res.on('data', function(d) {
        process.stdout.write(d);
    });
});

Your original question, however, was not about problems with the server side but rather a problem with the node code itself so this wouldn't be of much use here.

Answer 2

Use external HTTP Debugging tool. Your options include:

• node-http-proxy as seen in How do I use node.js http-proxy for logging HTTP traffic in a computer?
• middlefiddle written in node.js (but abandoned for 3 years now) https://github.com/mdp/middlefiddle
• mitmproxy - a CLI tool http://mitmproxy.org
• fiddler http://www.telerik.com/fiddler
• and many more - https://www.google.pl/search?q=HTTP+debugger

You fire up one of those, tell them where to route the traffic, and point your application at that debugging proxy instead of the real server.

Answer 3

I came to this question looking for something similar but I'm using the request package. In this case all you need to do is include this line in your code:

require('request-debug')(request);

(make sure request-debug package is installed)

This will print all the request data to the console.

Answer 4

If you are using a node version earlier than node 8, I'm a big fan of node-inspector:

https://github.com/node-inspector/node-inspector

I believe it has everything you are looking for:

Answer 5

If you only need to see URLs of outgoing traffic and what caused it, You can use debugging-aid

npm i -D debugging-aid
node --require debugging-aid/network app.js 

Resulting console output may look like this:

[aid] network, outgoing  to: http://example.com/
 stack:     at Agent.createSocket (_http_agent.js:234:26)
    at Agent.addRequest (_http_agent.js:193:10)
    at new ClientRequest (_http_client.js:277:16)
    at Object.request (http.js:44:10)
    at Request.start (myapp-path/node_modules/request/request.js:751:32)
    at Request.end (myapp-path/node_modules/request/request.js:1511:10)
[aid] network, outgoing  to: http://example.com/
 stack:     at Agent.createSocket (_http_agent.js:234:26)
    at Agent.addRequest (_http_agent.js:193:10)
    at new ClientRequest (_http_client.js:277:16)
    at Object.request (http.js:44:10)
    at get (myapp-path/node_modules/got/source/request-as-event-emitter.js:234:22)
    at Immediate.<anonymous> (myapp-path/node_modules/got/source/request-as-event-emitter.js:305:10)

---

Disclaimer:

I'm the author of debugging-aid
This answer was written when debugging-aid was on version 0.2.1