3

I want to get events from block X. I have:

quorum-v2.4.0
web3js 1.2.6

And I have my own smart contracts I want to listen for. So I have created listener for allEvents like this:

  const event = contract.events.allEvents({
    fromBlock: 0,
  });

And I also have following snippet of code where I am listening for the new events and also for the previous events. So I am specifying fromBlock as described in web3js documentation:

fromBlock - Number|String|BN|BigNumber (optional): The block number (greater than or equal to) from which to get events on. Pre-defined block numbers as "latest",

  event
    .on('data', console.log)
    .on('error', eventError);

When I dont specify fromBlock: 0, it doesnt return anything which is OK. When I set fromBlock to 0 it always return the last block (e.g block 6 - see below) even though there are more blocks before the block number 6:

Object {address: "0x9d13C6D3aFE1721BEef56B55D303B09E021E27ab", blockNumber: 6, transactionHash: "0x51f254852cc897d6d3e40041b3a3e5dd7ec9a5ebddd771d9…", transactionIndex: 0, blockHash: "0x0eaec149917f0517aa99042875313882aa57831b3d02aaf5…", …}

Based on the documentation I assume it should return all events from block number 0. So I should get events in block 0,1,2,3,4...latest.

Do I understand it correctly? Do I need to set some configuration? I want to workaround contract.getPastEvents and I want to set fromBlock within the subscription in listener.

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4
  • It actually depends on which node you're using I believe. For example, infura doesn't throw an exception on block 0, but alchemy does. Just set fromBlock to 1.
    – goodvibration
    Commented Feb 23, 2020 at 16:53
  • @goodvibration Thanks a lot for your comment. I tried set it to different numbers. If the latest number is smaller than fromBlock it doesnt return any event. However when I set fromBlock to something smaller than current latest block (let's say 10) it always return the previous one (in this example block 9). I also tried converting to hex with web3.utils.toHex(<fromBlock>) but it didnt help as well
    – VladoDemcak
    Commented Feb 23, 2020 at 18:21
  • Have you tried using a callback function with contract.events.allEvents?
    – sfmiller940
    Commented Feb 27, 2020 at 0:49
  • 1
    @sfmiller940 yes. didnt work... looks like there is a bug with connection in websocket provider for subscription in general. More details here github.com/ethereum/web3.js/issues/3389
    – VladoDemcak
    Commented Feb 27, 2020 at 12:23

2 Answers 2

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0

Currently, I am using web3 version 1.2.1, the below code is working for me. Please give toBlock as latest. So that web3 js will give you all the events for that range.

contract.getPastEvents('allEvents', {
    fromBlock: 0,
    toBlock: 'latest'
})
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1
  • 1
    Thanks. The getPastEvents works fine, but I dont want to use second web3 call with getPastEvents. What I want is to create the subscription with contract.events.allEvents and within this subscription I want to get the previous transactions as stated in documentation with fromBlock
    – VladoDemcak
    Commented Feb 24, 2020 at 6:48
0

In https://github.com/ethereum/web3.js/issues/3389 it turned out it was a bug. Fixed in web3 1.2.7

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