to have fetchOptions.lookup and fetchOptions.socketPath, node should expose undici.Agent

[loynoir]

What is the problem this feature will solve?

builtin fetch missing fetchOptions.lookup and fetchOptions.socketPath

$ npm add undici
$ node
Welcome to Node.js v18.15.0.
Type ".help" for more information.
> {Agent}=require('undici')
...
> await fetch('http://localhost/version', {dispatcher:new Agent({connect:{lookup:console.log}})})
localhost ...
> await (await fetch('http://localhost/version', {dispatcher:new Agent({socketPath: '/var/run/docker.sock'})})).json()
{
  Platform: 

What is the feature you are proposing to solve the problem?

$ node
Welcome to Node.js v18.15.0.
Type ".help" for more information.
> {Agent}=require('node:undici')
...
> await fetch('http://localhost/version', {dispatcher:new Agent({connect:{lookup:console.log}})})
localhost ...
> await (await fetch('http://localhost/version', {dispatcher:new Agent({socketPath: '/var/run/docker.sock'})})).json()
{
  Platform: 

What alternatives have you considered?

{FETCH_AGENT} = require('node:some_symbols')
Agent = fetch[FETCH_AGENT]

Related

nodejs/undici#421 (comment)

[hjain5164]

Hi @VoltrexKeyva, I would like to work on this issue. Can you give me some guidance to proceed on this?

[bnoordhuis]

I don't think node should be exposing all kinds of non-standard extensions. If you need more configurability, either use undici or node-fetch directly, or switch to node's own http client.

[loynoir]

dns and socket are server side fetch stuff.

I don't think node should be exposing all kinds of non-standard extensions.

If dns and socket is non-standard to fetch, there must be something wrong or imperfect.

[ottob]

I needed this for configuring tls client certificates (mutual tls / mtls) using the new core fetch client.

I think this is a quite common task for back-end initiated https requests, so it would be nice not having to install additional libraries for this.

ref: #48977

[bnoordhuis]

I'd say there's zero chance of this feature request getting implemented as-is but there's an open issue about exposing undici's global dispatcher: #43187

You can also pass in your own dispatcher to individual fetch() calls, as explained in e.g. #48977 (comment).

I'll go ahead and close this but keep an eye on the other issue.

[ottob]

You can also pass in your own dispatcher to individual fetch() calls, as explained in e.g. #48977 (comment).

Thanks for looking at this issue.

Sorry for the noob question, but how can this be done without also having to import undici to get access to the Agent as Alex did in that issue? The point was not having to import undici since it is already in core.

[bnoordhuis]

At least for now you can't get around importing undici into your project.