Selling NFT with ETH on Polygon – Pros and Cons

For future readers, apparently Polygon does not support eth_newFilter so a way to get events thru Web3 is subscribing to logs (currently available thru Web3.js) or using get_logs (if u wanna do it in python), I found an example in a reddit post, goes like this:

from web3 import Web3
from web3._utils.events import get_event_data

w3 = Web3(Web3.HTTPProvider("<Infura host>"))
contract = w3.eth.contract(address="0x33..", abi=abi['abi'])
event_template = contract.events.<EVENT_NAME>
events = w3.eth.get_logs({'fromBlock':from_block, 'toBlock': from_block+10000, 'address':"0x33.."})


def handle_event(event, event_template):
    try:
        result = get_event_data(event_template.web3.codec, event_template._get_event_abi(), event)
        return True, result
    except:
        return False, None

for event in events: 
    suc, res = self.handle_event(event=event, event_template=event_template)   
    if suc:
        print("Event found", res)

Its in the current version of Opensea/WyvernV2/Ethereum not possible. Every call Wyvern Contracts are sending to your contract/NFT are external calls. Within these calls you will only have access to call-related data of the specific call Wyvern does to your contract (e.g. token-id, sender, receiver in safeTransferFrom) and general block-related data (e.g. block hash, block time). Since in no call Wyvern sends information about the msg.value of the initial transaction, your smart contract will not have access to this value. Besides sending the token I cant find any other interactions with the token contract which would allow to identify any changes in account balances.

In general Wyvern Protocol sends price information through a staticcall (see staticTarget and staticExtradata of atomic match function), however, I am pretty sure that Opensea API does not allow you to specify the staticTarget on a collection.

But, there are some solutions in case you are in control of seller, buyer or payment token. E.g. you could implement allowing only specific Seller/Buyer and create based on that a centralized work-around solution.