isIdempotencyConflict: error combining mailgun-js and gocardless-nodejs

[XavierColombel]

I ran into a bug when I import mailgun-js and gocardless-nodejs libs in the same project.

Here is the error message I got:

(node:62883) UnhandledPromiseRejectionWarning: TypeError: Cannot read property 'statusCode' of undefined
    at Api.isIdempotencyConflict (/Users/johndoe/Github/johndoe-admin/node_modules/gocardless-nodejs/api/api.js:125:26)
    at Api.request (/Users/johndoe/Github/johndoe-admin/node_modules/gocardless-nodejs/api/api.js:58:22)
(node:62883) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:62883) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

You need to install 3 libs to reproduce the problem:

npm i mailgun-js gocardless-nodejs cuid

Here is the full code you can use (don't forget to add your GoCardless PRIVATE_API_KEY):

const mailgun = require("mailgun-js");
const constants = require("gocardless-nodejs/constants");
const gocardless = require("gocardless-nodejs");

const cuid = require("cuid");

(async function () {
  const client = gocardless(
    "XXXXXX_PRIVATE_API_KEY_XXXXXX",
    constants.Environments.Sandbox
  );

  const session_token = cuid();
  const redirectFlow = await client.redirectFlows.create({
    description: "my product",
    session_token,
    success_redirect_url:
      "https://anyredirecturl.com`,
    prefilled_customer: {
      given_name: "john",
      family_name: "doe",
      email: "johndoe@domain.com",
      company_name: "JD Company",
      address_line1: "Hi",
      postal_code: "12334",
    },
  });
})();

It might be an error with the got lib GoCardless uses.

[lancscoder]

Hi @XavierColombel,

Thanks for getting in touch.

After looking into this it looks like mailgun-js is using an old version of agent-base (version 4) which is monkey patching https (https://github.com/TooTallNate/node-agent-base/blob/4.3.0/patch-core.js) and this is causing the issue. Any https call that is made will fail, see below example:

var got = require('got');
var mailgun = require('mailgun-js');

(async () => {
  var httpWorking = await got('http://www.google.co.uk');

  console.log(httpWorking);

  var httpsNotWorking = await got('https://www.google.co.uk');

  console.log(httpsNotWorking);
})();

This bug/issue is fixed in agent-base version 5 and above. I'd reach out to the authors of the mailgun-js library and see if they can update their dependencies.

[XavierColombel]

Thanks @lancscoder . I've switched to Axios request because it seems their mailgun-js lib is not maintained anymore...