feature request: support additional networks in the Etherscan provider

[mds1]

Right now only mainnet and testnets on the etherscan.io domain are supported by the EtherscanProvider

However, it'd be great if we can support other Etherscan-run sites that share the same endpoints

• https://optimistic.etherscan.io (and the testnet equivalent) should be the simplest since you can use the same default API key
• https://polygonscan.com/ and https://arbiscan.io/ (and the testnet equivalents) are different domains and would need different API keys

I believe each of the above supports the same set of APIs as L1, though have not yet verified any except the txlist one. Even if they don't, we could move the "unsupported network" error to the specific unsupported methods instead of the constructor. Perhaps with a try/catch where we optimistically try the endpoint so we don't need a new ethers release to handle the case where Etherscan adds a new endpoint that wasn't previously supported by a network

For context, my particular use case is that in Umbra we use the getHistory method to find a transaction sent by the specified address, then back out their public key from the transaction data. Lack of polygon support blocks our "advanced mode" functionality on polygon, so I'm happy to get a PR in for this in v5 if that'd help speed things up. (Of course we could use the Etherscan API directly as an alternative, but this is cleaner—just let me know where to source the default API keys from).

[ricmoo]

This is absolutely easy to do in v5, functionality was added a while ago to make this easier. If you want to throw something together sooner than later, see the BscscanProvider.

In v6, the EtherscanProvider supports a NetworkPlugin to change this, so the network object is sufficient to modify the EtherscanProvider configuration, so it will work out if there box.

[mds1]

Ah I see, you're suggesting extending EtherscanProvider to create a custom class that supports all networks we need, instead of PR'ing support for each network into ethers? At first I thought the BscscanProvider was part of ethers.js and it wasn't clear to me why it needed to be a separate class, but extending it ourselves makes sense and seems very simple

[ricmoo]

Exactly. That way only people who require less common networks have to incur the overhead and file size increase. :)

[mds1]

Perfect, will do. Thanks for the quick response! 🙂

[ricmoo]

(and I can add the provider in ancillary packages for polygon, et al. in the future too; it also means I can set alternate repo owners so someone else can be responsible for maintaining it ;))