Error ECONNREFUSED when connecting to database

[OliverMoscow]

Expected Behavior

Couchdb nano should connect to database.

Current Behavior

My couchdb server is running at localhost:5984. curl requests from terminal work fine.

In a next.js api endpoint:

const nano = require("nano")(`http://${user}:${pass}@localhost:5984`);
const db = nano.db.use("patients")
db.info().then(console.log)

when I run this I get:

error - unhandledRejection: Error: error happened in your connection
    at responseHandler (/Users/omoscow/Desktop/couch-test/node_modules/nano/lib/nano.js:137:16)
    at /Users/omoscow/Desktop/couch-test/node_modules/nano/lib/nano.js:427:13
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Possible Solution

Steps to Reproduce (for bugs)

1. Create a fresh next.js application with npx create-next-app@latest
2. npm install nano
3. In the hello.ts file type:

const nano = require("nano")(`http://admin:couchhie8394@localhost:5984`);
const db = nano.db.use("patients")
db.info().then(console.log)

4. npm run dev

Context

Your Environment

• Version used: 10.1.0
• Browser Name and version: Chrome 106
• Operating System and version (desktop or mobile): Mac OS Monterey
• Link to your project:

[glynnbird]

My variation on your test script works just fine:

const nano = require("nano")(process.env.COUCH_URL);
const db = nano.db.use("mydb")

const main = async () => {
  const i = await db.info()
  console.log(i)
}

main()

[AdrianoFerrari]

I had the same issue (curl and other ways of connecting with CouchDB worked fine, nano failed with ECONNREFUSED).

I was using Node 18. Based on this SO answer I downgraded to Node 16 and it worked.

[glynnbird]

That's interesting. I'll try with node18

…

On Sat, 19 Nov 2022, 00:34 Adriano Ferrari, ***@***.***> wrote: I had the same issue (curl and other ways of connecting with CouchDB worked fine, nano failed with ECONNREFUSED). I was using Node 18. Based on this SO answer <https://stackoverflow.com/a/73146534/43769> I downgraded to Node 16 and it worked. — Reply to this email directly, view it on GitHub <#313 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAFKMRJUUWRHS6DYSZ4E2DLWJAOAVANCNFSM6AAAAAARXMG7ZI> . You are receiving this because you commented.Message ID: ***@***.***>

[glynnbird]

Just tried with 18.12.1 and it worked fine when connecting to a remote CouchDB API over https but failed when connecting to a local CouchDB over http. I'm going to investigate that further. As @AdrianoFerrari notes, changing to Node 16 fixes the problem.

I've confirmed the same happens with just plain old axios e.g

  axios.request({url: 'http://localhost:5984/mydb', method: 'get'})

so it's nothing special about Nano per se.

[glynnbird]

It appears to be to do with the way that "localhost" is interpreted.

In Node 16, localhost ===> 127.0.0.1
In Node 18, localhost ===> ::1, which is an IPv6 address

Note that in a default Mac /etc/hosts file there are two references to localhost:

127.0.0.1          localhost
::1                localhost

So it appears that in Node 18+, it's preferring the IPv6 option.

i.e. if you change your code to

const nano = require("nano")(`http://${user}:${pass}@127.0.0.1:5984`);

then it'll work.

[glynnbird]

So this is down to how Node.js resolves DNS hostnames.

In Node v16, calling the built-in function dns.lookup returns 127.0.01 and in Nodev18 it returns ::1, the IPv6 equivalent.

Given a URL with a localhost hostname, Nano will inevitably behave differently between Node versions 16 and 18 as Node's DNS resolution function has changed to prefer the IPv6 address first. A Mac's /etc/hosts file contains entries like:

127.0.0.1          localhost
::1                localhost

CouchDB doesn't listen on IPv6 addresses, as by default it's bound to 127.0.0.1 and changing this to 0.0.0.0 will only bind it to all IPv4 addresses.

There are a number of solutions:

1. Use 127.0.0.1 instead of localhost in your URLs. This forces IPv4 and obviously doesn't require DNS resolution.
2. Use a domain name instead of localhost. Create an entry in your /etc/hosts like 127.0.0.1 my.pretend.host and use that your hostname in the URL you feed to Nano.
3. Remove the ::1 localhost entry from your /etc/hosts file.
4. Stick to Node v16.
5. Make CouchDB bind to an IPv6 address by changing bind_address = ::1 in couchdb.ini. You can then do curl 'http://USER:PASS@[::1]:5984/.