Axios gives a 504 error on a Windows VM

[nareshbhatia]

#### Summary

The following node.js app using Axios works correctly on Windows and Mac:

var SERVER_URL = 'http://localhost:3000';

var axios = require("axios");

function getBooks() {
    return axios
        .get(SERVER_URL + '/books')
        .then(function(response) {
            return response.data;
        });
}

getBooks()
    .then(function(books) {
        console.log(JSON.stringify(books, null, '    '));
    });

However, if I run it on a Windows 7 or Windows 10 VDI (essentially a virtual machine), it fails with the following error message:

(node:12000) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): Error: Request failed with status code 504

If I replace the axios call with node-fetch, the error goes away and the fetch works. What could be the problem with axios or the way I am using it?

#### Context

• axios version: v0.16.2
• Environment: node v6.11.0, windows 7, Windows 10 running in a VDI

[ZhangYiJiang]

That warning means that the Promise is getting rejected - you should attach a rejection handler to catch it and see what the error is

getBooks()
    .then(...)
    .catch(function(error) { 
        // Do something with error, like logging
    }); 

[nareshbhatia]

@ZhangYiJiang, thanks for helping out. I am now catching and logging the error returned by axios. It says:

(node:13728) UnhandledPromiseRejectionWarning: Unhandled promise rejection (rejection id: 2): TypeError: Converting circular structure to JSON.

Unfortunately, there is no circular structure in the returned JSON. I can hit the same URL from the browser and I get simple objects with two properties (id and name):

[
  {
    "id": "design-patters",
    "name": "Design Patterns"
  },
  ...
]

[nareshbhatia]

If I put a breakpoint in the catch clause, and inspect the error object, I am getting a 504 error from a gateway inside the firewall. The response is an HTML page displaying the 504 error. I wonder the app it is trying to reach an outside port instead of localhost where the server is running.

[nareshbhatia]

Ok, I think I have determined the root cause of this issue, but don't know the solution.

The Windows VM has HTTP proxy settings by setting the environment variable HTTP_PROXY (there is also one called HTTPS_PROXY). For some reason, Axios thinks that it needs to go through the proxy to access http://localhost:3000. Bottom line, it is hitting the proxy, which is returning the 504 error. It is not even hitting the server at http://localhost:3000. If I remove the environment variable, then the problem goes away.

So the question is, should Axios be going through the proxy to access local ports when HTTP_PROXY is set? What is the right way to solve this issue? The HTTP_PROXY variable is required for other applications to work correctly.

BTW, node-fetch seems to be ignoring the HTTP_PROXY variable and works fine even if it is set. I don't know if that's good or bad!

[nareshbhatia]

After a bit of research, I found that I should set NO_PROXY to exclude hosts that should not go through the proxy. So I set up NO_PROXY as follows:

set NO_PROXY=localhost,127.0.0.*

Unfortunately that doesn't work. Then I stumbled across #434 which has been open since Sep, 2016. Furthermore there is a PR for it, ready to be merged since Dec, 2016: #565. I am baffled why something as important as this has not been merged in 8 months! My faith in Axios is shaken :-(. Please prove me wrong.

[rubennorte]

We'll review that PR so I'm closing this as duplicate.