Web3.js: contract.events.Transfer subscription missing events

Created on 27 Jan 2018 · 7Comments · Source: ChainSafe/web3.js

I'm subscribing to token transfer events for OMG using the code below

   let contract = new web3.eth.Contract(this.abi, this.omgContractAddress);    
        contract.events.Transfer({}, (err,data) => {
            if(err)
                console.error(err)
            if(data)
                  console.log(`OMG Transfer: block:${data.blockNumber} ${data.returnValues.to} received ${data.returnValues.value/1000000000000000000}. txHash:${data.transactionHash}`);
        });

This is working and logs to the console however it does not take long for a missing transfer to become evident:

OMG Transfer: block:4979638 0x16ae5217Fa04E9827508900C1C2f64f8EF91183b received 29.36. txHash:0xa55bc6b01048b4ec161cc8ca3bd119234a08aaa54e4a4f852d2bfe12885ca566
OMG Transfer: block:4979643 0xAC949Fd4c2204A19eA7d947c2e2841F3B0433A7f received 21.39896667. txHash:0x130a855aa470dc519d294871fc89349985d6f6465d6ac0a03738c2c1e08d7a05
*missing from block 4979644 0x0b184d2aa2193ea492a79ed894b2bee14cc7321e95038f54f98f1dab2d60befd from block *
OMG Transfer: block:4979646 0x06d58A4A17301402b216B5AEa613aEa99E78A5D9 received 5338.28022204. txHash:0x07bf2db1d62e2b60d19253fec9d0fdef2208baa6f6d19e2649b846b3450268b5

You can just run it from the latest block to see this behaviour.

Interesting if you call getPastEvents then the missing Transfers from above are present

bug

Source

wallaceturner

All 7 comments

I am have this issue as well with a different event. Just seemingly randomly misses events. I too seem to get them correctly after running getPastEvents - I wonder if you miss event on large sets of events?

I use the on listeners, no data, changed or error events fired.

[email protected]
parity v1.9.4

dafky2000 on 28 Mar 2018

the same issue, randomly misses events while listening on local node

geth 1.8.2-stable
[email protected]
node.js v8.11.1

krogla on 12 Apr 2018

same here...

parity 1.9.4-1.10.1
[email protected]
node.js v8.9.4

bytniak on 23 Apr 2018

const Web3 = require('web3');
const web3 = new Web3(new Web3.providers.WebsocketProvider(env.BC_ROPSTEN_URL_HTTP));
var contractObj = new web3.eth.Contract(JSON.parse(contract.dataValues.contract_abi),
                contract.dataValues.contract_address);
            //log(contractObj)
            contractObj.events.Transfer({}, (err, tran) => {
                if (err)
                    log('Error in subscribed event : ', err);

getting error while subscribing event

Error: connection not open
1|ICOWalle |     at WebsocketProvider.send (/var/www/TLPICOWalletApp/node_modules/web3-providers-ws/src/index.js:247:18)
1|ICOWalle |     at Timeout._onTimeout (/var/www/TLPICOWalletApp/node_modules/web3-providers-ws/src/index.js:232:19)
1|ICOWalle |     at ontimeout (timers.js:482:11)