Add dns caching by default

[ronag]

Something like: https://github.com/szmarczak/cacheable-lookup#readme

Should be an option to disable.

[SimoneDutto]

Hi,
I would like to work on this.
What do you mean by adding this to undici?
Is the behavior needed or the whole library?

This would be my first time contributing to an Open Source Project, but I want to start contributing!

[MrSharpp]

can you state some instructions, where its code should be written?

[Medhansh404]

Hey!
I'm currently tackling issues #2440 and #1066. My focus is on enhancing the DNS cache lookup functionality. I plan to intercept DNS requests, check the cache before reaching out to the server, and address other caching aspects.

However, I'm facing difficulty locating the specific code related to fetch requests and DNS resolution commands within the files. Your help in navigating and identifying these components would be immensely appreciated!

[Medhansh404]

"I can come up with ways to approach this issue Planning to add DNS cache lookup. Considering two ways: 1) Middleware like HTTP dispatcher in 'lib,' or 2) Custom Resolver globally. would appreciate if I can get a head's up on the approach and which one will be better(if any) !!! @ronag

[metcoder95]

The more pragmatic the approach, the better; I'd suggest you take a look at how Socket#connect handles the lookup aspect when establishing a connection; and maybe seek something down that line

[antoinegomez]

I had a look last evening and the easiest way I think is to do like @metcoder95 suggest by using the lookup option in the socket module.

My PR is not yet ready, need to finish implementation and refactor a bit. This was mostly to play and see if it works.
I will not implement all options like in this module, otherwise why not simply copy/paste it or add it as a peer dependency and provide an option to configure.

Not sure how to make it configurable in the fetch method to keep it rfc compliant.
Could also have a global config for all requests made via undici.

[KhafraDev]

@ronag feel free to reopen but as you mentioned it's already possible to do this

import CacheableLookup from 'cacheable-lookup';

const cacheable = new CacheableLookup(opts)

const agent = new Agent({
  connect: { lookup: cacheable.lookup }
})

[metcoder95]

No strong opinion on this, but I see the potential in having it within core; maybe it will require more thought but as @KhafraDev suggests, is already doable by third-party