Axios calling request setHeader with function as value

[KrayzeeKev]

Describe the bug

Axios is calling request.setHeader with a function as the value and this is causing nock to throw an error. I see nothing in the NodeJS documentation saying that a function is a valid value for a header (I was guessing perhaps you could provide a function it would call but there is nothing in the docs to suggest that). As such, I'm starting with this as an Axios bug and not a deficiency in nock's implementation of Request.

It seems this is triggered by using axios-retry.

If, however, passing a function to request.setHeader is a valid thing, I'll close this and raise something on nock.

The function being passed to request.setHeader is the "get" method in the AxiosHeaders prototype.

function(header, parser) {
    header = normalizeHeader(header);
    if (!header) return undefined;
    const key = findKey(this, header);
    if (key) {
      const value = this[key];
      if (!parser) {
        return value;
      }
      if (parser === true) {
        return parseTokens(value);
      }
      if (utils.isFunction(parser)) {
        return parser.call(this, value, key);
      }
      if (utils.isRegExp(parser)) {
        return parser.exec(value);
      }
      throw new TypeError('parser must be boolean|regexp|function');
    }
  }

The error returned by nock's request.setHeader is: TypeError [ERR_INVALID_CHAR]: Invalid character in header content ["0"]

To Reproduce

'use strict';

const nock = require('nock');
const axios = require('axios');
const axiosRetry = require('axios-retry');

nock('http://localhost')
  .get('/')
    .times(2)
    .query(true)
    .delay(10000)
    .reply(200, [])
  .get('/')
    .reply(200, []);


const ax = axios.create();
let retryCount = 0;
axiosRetry(ax, {
  retries: 3,
  shouldResetTimeout: true,
  retryCondition: err => {
    if (err.code === 'ECONNABORTED' || axiosRetry.isNetworkOrIdempotentRequestError(err) ) {
      console.warn(`Timeout - RETRY ${++retryCount}`);
      return true;
    }
    return false;
  },
});

ax( {
  url: 'http://localhost',
  method: 'GET',
  timeout: 1000
}).then(resp => console.log(resp.data));

Expected behavior

It should get a timeout error twice and then receive and log an empty array.

Environment

• Axios Version 1.1.0
• Node.js Version 18.7
• Additional Library Versions axios-retry 3.3.1, nock 13.2.9

[chrno1209]

I am having the same issue, had to do a work around by removing all invalid headers (using interceptor) before sending request.

[grenik]

Seems relevant to #5089 which shall be fixed in #5090

[KrayzeeKev]

@grenik Apparently, #5090 is done and merged. Or replaced with #5162. NOT FIXED. #5162 is merged and current v1.x branch has the same fault.

[DigitalBrainJS]

On Axios v0.27.2 that code logs:

Timeout - RETRY 1
Timeout - RETRY 2
Timeout - RETRY 3

node:internal/process/promises:279
            triggerUncaughtException(err, true /* fromPromise */);
            ^
AxiosError: Nock: No match for request {
  "method": "GET",
  "url": "http://localhost/",
  "headers": {
    "accept": "application/json, text/plain, */*",
    "user-agent": "axios/0.27.2" // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
  }
}

On Axios v1.1.3 with PR #5224

Timeout - RETRY 1
Timeout - RETRY 2
Timeout - RETRY 3

file:///H:/JS/forks/axios/lib/core/AxiosError.js:89
  AxiosError.call(axiosError, error.message, code, config, request, response);
             ^
AxiosError: Nock: No match for request {
  "method": "GET",
  "url": "http://localhost/",
  "headers": {
    "accept": "application/json, text/plain, */*",
    "user-agent": "axios/1.1.3", // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
    "accept-encoding": "gzip, deflate, br"
  }
}

It's hard to tell whether the issue is covered by the PR if the error is not reproducible on v0.27.2, but Axios will support an AxiosHeader instance as the headers config.

[KrayzeeKev]

@DigitalBrainJS I'm sorry. I had removed an actual URL in favour of a fake one so the successful call at the end never happened. Added another .get to the nock call above.
I also removed the .default from the axios require which was legal in the early 1.x releases still, I think but has become illegal now. There's a PR for the next release that puts it back. But it does nothing.
Code above should now behave as advertised.

[KrayzeeKev]

@DigitalBrainJS Any chance of having a look at this with the revision I made?