Questions tagged [events]

Solidity events and logging problems. Events allow the convenient usage of the EVM logging facilities, which in turn can be used to “call” JavaScript callbacks in the user interface of a dapp, which listen for these events.

163 questions with no upvoted or accepted answers
Filter by
Sorted by
Tagged with
6
votes
1answer
2k views

Etherscan: Effectively paginate `Event Logs` result

I am using Etherscan API for various Ethereum details. I need to find out the tokens transferred from a token original contract (let's say A) address to a particular address(let's say B). For this ...
5
votes
0answers
796 views

Problem with multiple event listeners, duplicated event triggers

In my app i have multiple listeners (watchers) on different events of same contract. Nothing complicated. let songAddedEvent = instance.SongAdded({}, { fromBlock: 'latest', toBlock: '...
4
votes
1answer
854 views

Events not being detected in Nethereum

I have a function in one contract that looks like this: //Events event RequestReceived(bytes s); event WorldCreated(bytes32 indexed worldName, address indexed sender, address result ); ...
4
votes
2answers
623 views

Web3 Event Filtering timeout

This is the code I use to get all events from a certain contract. Solidity: event NewEvent(address indexed contractAddress, address newBOPAddress, address payer, uint commitThreshold, bool ...
4
votes
0answers
422 views

Event and/or watch does not work

I have a contract for a simple bidding scenario as below: pragma solidity ^0.4.9; /* Contract accepting biddings during 30 minutes */ contract SimpleBidding { address contractOwnersAccount; ...
4
votes
0answers
480 views

sendTransaction and events not working in NodeJS app

I have a contract deployed on the testnet, I can do the following within geth: reference.transfer.sendTransaction(bob, 467, {from:me}) However I can't do this within my node console (with web3 etc. ...
3
votes
0answers
251 views

The sendSignedTransaction function does not activate the on('receipt') event at an appropriate time

console.log(transacting...); web3.eth.sendSignedTransaction('0x' + serializedTx.toString('hex')).on('receipt', receipt => { log(receipt); log(`https://ropsten.etherscan.io/tx/${receipt....
3
votes
2answers
112 views

is it possible to get events from transactions that are in the `txpool`?

Is it possible to see the events that will be emitted in the txpool, or is only the transaction information available? For example, can I search in either the queued or pending transactions and ...
3
votes
0answers
465 views

How to use logx in Solidity?

Aim: To log data from a smart contract. Following function is written in accordance with low level interface to Logs in ethereum. However, due to lack of documentation, and being new in Solidity, I ...
3
votes
1answer
288 views

How to access non-indexed event arguments from Go types.Log?

The Go bindings have a type called Log that has the following fields type Log struct { // Consensus fields: // address of the contract that generated the event Address common.Address `...
3
votes
0answers
771 views

ERC20 Transfer Event error or intended?

I'm trying to get an Event "Transfer" for the ERC20 Token with web3 function getTransactionReceipt event Transfer(address indexed _from, address indexed _to, uint256 _value) You can see the term ...
3
votes
0answers
119 views

Contract works fine in Solidity-browser but not against private node

I have been testing a contract using the Solidity Browser, but when I deploy the same contract on my private node, it doesn't seem to work the same as in the Solidity Browser. I have tried manually ...
3
votes
3answers
266 views

How to setup 'topics' for function getPastLogs ()?

Sir, I want to read the past event log by using getPastLogs(),but I got the whole log.I hope I can filter some log. I find I can setup the 'topics' in getPastLogs(),but it always fails. How ...
2
votes
0answers
67 views

How can I extract sidechains (transient forks) from a geth node before they get discarded?

According to my understanding, transient forks (also known as sidechains in geth's source code) are discarded or overwritten when a reorganization happens. But before that, when the node detects a ...
2
votes
0answers
46 views

Accessing the network through light node

I've been trying, unsuccessfully, to make a web3.py app that needs to catch events, with the use of filters. After hours and hours of testing it appeared the problem was that Infura, which is the ...
2
votes
0answers
74 views

Truffle test to verify events can be queried by the address of the signing user?

I'm trying to write a test which verifies I can query a given type of events by the user/address which sign them. I would like to apply TDD (relevant to say I haven't made the implementation for this ...
2
votes
1answer
223 views

Reliable way of listening to events on frontend

I make a web application, that needs the events from my contract to initialize it's state. I was using infura websocket provider, but it seems to lag a lot and close the connections unexpectedly ...
2
votes
1answer
526 views

How to unsubscribe logs / events?

There are two ways to subscribe/watch to logs/events: Subscribe: var subscription = web3.eth.subscribe('logs', { address: '0x123456..', topics: ['0x12345...'] }, function(error, result){ ...
2
votes
1answer
112 views

Parity warp sync doesn't return event logs

Our Dapp uses events as a form of storage. For connection to blockchain we use local Parity node. A couple of days ago I needed to resync it after the server failure. After the resync all methods ...
2
votes
1answer
291 views

How to filter indexed events and watch callback return value using Web3.py

For example, I have an event where using clusterAddress as key, I want to find the other arguments (storageID, desc, etc.), only having the clusterAddress indexed. I added the indexed keyword for the ...
2
votes
2answers
414 views

How do I use filter EVM log events by an indexed field in web3j?

I've looked through the documentation, but there doesn't seem to be this scenario listed. What I want to do is filter the Ethereum event log of a specific contract by an indexed field with Web3j. ...
2
votes
1answer
367 views

Healtcheck on Websocket

I've looked through the documentation and haven't found that to be helpful. I would like to know the best way to do a healthcheck on my websocket connection to geth (Yesterday, I found out that I did ...
2
votes
1answer
53 views

Unable to print event without JSONstringify

I am trying to understand the difference among following cases while printing the event: At web3.js listenToEvent: function(){ Contract.deployed().then(function(instance){ instance....
2
votes
1answer
212 views

Alternatives to listen Events contract with web3.py?

I'm facing some issue/bug on web3.py, I need to listen my event contract, but event logs are always empty. I know the following issue on Ganach-CLI but may be there is other alternative. I already ...
2
votes
0answers
298 views

Parity syncing status for smart contract events with warp

So I'm trying to find the fastest way to fully sync a parity node in order to get all smart contract events, not just account states. The problem I've found is that when parity has warp syncing ...
2
votes
0answers
195 views

Web3 js events not listening after 5 mins of idle time

My contract is deployed on ropsten infura test-network and that contract has events which gets fired when there is some transaction. contract file function functionName(address from, address ...
2
votes
0answers
133 views

(1) Parity: why does syncing fall behind, (2) Why are events missing events because of (1)

Background: I have multiple parity nodes setup on Digital Ocean and AWS and event watchers attached to these nodes. I also have a service to query block numbers and compare versus etherscan's current ...
2
votes
1answer
979 views

Subscribe to events usign geth websocket

I'm trying to subscribe to geth using the websocket api. First step was to start geth: geth --ws --wsport=8456 --wsorigins="*" --fast --cache=512 --rpcport=8455 --rpc --rpcapi="personal,eth,network" ...
2
votes
1answer
181 views

Indexed arguments can't be retrieved, why?

Indexed arguments will not be stored themselves. You can only search for the values, but it is impossible to retrieve the values themselves. This is a quote from the following docs: http://...
2
votes
1answer
76 views

event not returning expected data

When I start my app I listen for posts from the latest block. After a post has been made I'm supposed to return author (address), title (string) and an id (uint). But what I get in the author and id ...
2
votes
1answer
287 views

Can we call two contracts in web3.eth.filter method?

I have two contract address and I want to check events on both in one call. I mean, can we pass two contract address in one option param like i do below? let web3 = new Web3(); web3.setProvider(...
2
votes
1answer
319 views

convert padded topics address to valid address string

I am parsing some information from the topics array. I receive 32bit padded addresses in some indexes. Is there a web3 utility function or useful helper method to get these back into normal sized ...
1
vote
1answer
24 views

Correct approach of replicating smart contract balances

We are storing user balances on smart contract and as well as on our local db, so that we dont always have to query blockchain for user balance. For this we use contract events to update balances ...
1
vote
0answers
30 views

What is the maximum size of ABI in real world contracts?

To monitor my contracts during development and test in a private blockchain I’ve written an event explorer that encodes beside other parameter the ABI in an URL parameter. The ABI will be compressed ...
1
vote
0answers
18 views

Websocket provider reconnects every 1 minute

I'm developing an application on a private Ethereum chain and trying to listen to some events. I wrote a basic indexer script for listening to events and writing them in a database. To listen to the ...
1
vote
0answers
34 views

listening for solidity event with Javascript

I am attempting to make a simple guessing game. Game rules: Player 1 initiates the game with a contract address, upper bound, lower bound and answer. Player 2 has 10 guesses to guess the answer or ...
1
vote
0answers
51 views

How does function getPastEvents works? It's too quick

I'm trying to understand how .getPastEvents function works. When given block range to search is {fromBlock:0, toBlock: 'latest'} it finds my events almost instantaneously. Shouldn't filtering all 7M ...
1
vote
1answer
34 views

Watching for events

How come sometimes events show up on block explorers in hex and sometimes to you can see the actual string name of the event in the logs. I ask because my event watchers on my front end only pick up ...
1
vote
1answer
55 views

Stop watching events

I have activated watching events with Contract.events.events_name(filter, lastBlock), now I need to stop watching this event. I can't find the command in web3 docs. I'm using Web3 version: 1.2.1. How ...
1
vote
0answers
226 views

Ganache is not showing any events

I have a contract method which emits events but ganache seems not to catch any events. I say this because when I deploy my contract on ropsten the events are being caught fine but only in ganache I ...
1
vote
0answers
25 views

How a contract on Ropsten (deployed after fork) emit 3/5 events on the shorter chain while same contract on longer chain emits 5/5 of the events

General info: We have a full-node, which broadcast our txs. We have a EventSource contract which contains 5 events types. The eventSource contract deployed only after Istanbul fork. Our node was ...
1
vote
1answer
41 views

Subscribe to events using local geth in light mode?

I've followed this guide to subscribe to events. I succesfully subscribed to the new block headers using Infura provider. But when I try to use local geth node syncing in light mode, it connects, but ...
1
vote
0answers
32 views

How I can get parity logs for non-mainchain blocks?

There's no much info on how parity event log works. What happens to event logs that correspond to block which is not mainchain anymore? Are they unrecoverably lost? For such an occasion, is there any ...
1
vote
0answers
45 views

How to filter MyEvent({ },{ }) to retrieve only the latest transaction in the array?

My code: instance.MyEvent({}, {fromBlock: 0, toBlock: 'latest'}).watch(function(error, event) { if (!error) { console.log(event); $('#events').html(event.transactionHash); } else { ...
1
vote
1answer
40 views

Events in hub/factory contract

I have written a contract with the hub/factory pattern in which I need to capture the address of the contract that is being created, for this I am using events. Contract A Function A1 -- Call to ...
1
vote
0answers
26 views

Can't get event data selecting the event by name

This is my contract pragma solidity ^'0.5.2'; contract MyContract { event ContractCreated(address newAddress); constructor() public { } function createOtherContract() public { ...
1
vote
0answers
60 views

Web3 Daemon Event listner

const DManage = new web3.eth.Contract(myABI, '0x9420D0904B2F696f8612239e5a507A86B5dA1b6a'); DManage.events.allEvents() .on('data', (response) => { console.log(event); }) .on('changed', (...
1
vote
0answers
59 views

How do newHeads and event subscriptions behave on past reorgs?

Based on the geth documentation, I understand that a subscription on both newHeads and logs will emit all new heads and events that come from a reorg. However, I couldn't find what the behaviour is ...
1
vote
0answers
16 views

One rpc connection faster than another

I have four synced peer nodes running on two separate machines. Nodes 1-3 have been around since the beginning of the block chain and are all on one machine while Node 4 was just added around block ...
1
vote
1answer
390 views

Call `getPastEvents` with Drizzle raise error: “getPastEvents is not a function”

Calling getPastEvents with Drizzle will cause the exception: TypeError: this.drizzle.contracts.Contract.getPastEvents is not a function How to get all the past events in an array (in-one-shot) ...