ENS.fromWeb3 not copying middleware

[Uxio0]

• Version: 5.10.0
• Python: 3.8
• OS: linux

What was wrong?

I would expect that after configuring a Web3 instance, if I do ENS.fromWeb3(w3) it would copy the middleware and parameters needed. Instead, it just uses the provider. This is very important for using ENS with Rinkeby and Geth, as it needs the POA middleware.

Steps to reproduce:

Initialize instance of Web3, add middleware for POA and then create an ENS instance from that.

How can it be fixed?

Copy web3 instance or allow to provide one.

[wolovim]

Thanks for the report. Seems like a reasonable expectation.

I see that fromWeb3 just peels the provider off of the web3 instance passed in, because ENS accepts a provider. Upon creation, there's also some adding and removing of middleware as a result of the init_web3 method.

@pipermerriam @carver thoughts on passing/cloning a web3 instance into ENS to preserve the middleware onion? Was this avoided in the past for any reason? If you like the idea, do you have a preferred implementation?

[carver]

Yeah, there are definitely some quirks there. But I think they're all managed by the methods @marcgarreau already found at

web3.py/ens/utils.py

Lines 77 to 96 in 6258d2e

	def init_web3(provider: 'BaseProvider'=cast('BaseProvider', default)) -> '_Web3':
	from web3 import Web3 as Web3Main
	if provider is default:
	w3 = Web3Main(ens=None)
	else:
	w3 = Web3Main(provider, ens=None)
	return customize_web3(w3)
	def customize_web3(w3: '_Web3') -> '_Web3':
	from web3.middleware import make_stalecheck_middleware
	w3.middleware_onion.remove('name_to_address')
	w3.middleware_onion.add(
	make_stalecheck_middleware(ACCEPTABLE_STALE_HOURS * 3600),
	name='stalecheck',
	)
	return w3

So the bulk of the work is to pass in a "template" w3 instance and copy the existing middlewares & provider, as a kind of alternative to init_web3(), then apply customize_web3()

(Also a reminder that @Uxio0 will have to pass addr into ENS.fromWeb3() for non-mainnet usage, since ENS is hosted at a different addresses on different networks IIRC)