Listen to same event across multiple contracts.

[Benjythebee]

Heya,
I have these contracts that have all the same ABIs and therefore the same events.
My goal is to efficiently listen to these events across all contracts.

The way I used to do it is, instantiate each contracts and add a listener to each contracts.

       this.contract.on('TransferSingle', (operator, from, to, id, value) => {
         transferSingleHandler(this, operator, from, to, id, value)
       })

However this is definitely not scalable and not efficient at all.

Given all contracts have the same ABI, there has to be a way I can listen to all these events... right?
Any ideas?

[zemse]

For more efficiency, I'd suggest you to use low level rpcs directly e.g. eth_getFilterChanges. The eth_newFilter (specs) allows you to specify multiple addresses.

const filterId = await provider.send('eth_newFilter', [{
  address: ['0x123..', '0x456...'],
  fromBlock, toBlock, topics
}])

const logs = await provider.send('eth_getFilterChanges', [filterId]);

Good with the filter API is that, if the chain was reorged such that event which you added in db is now no longer part of the longest running chain, it tells you that with a removed boolean.

[EvolveArt]

Hello !

I've implemented your solution and it always returns { "jsonrpc": "2.0", "id": 73, "error": { "code": -32000, "message": "filter 0x853b0a8fe6a65eb1ba2fbdc83af57177 not found" } }

If you have any idea why it does that, hit me up !