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.

186 questions with no upvoted or accepted answers
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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
996 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
933 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
671 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
481 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. ...
4
votes
1answer
366 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 ...
3
votes
0answers
259 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
175 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
544 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
320 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
780 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
120 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
370 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
74 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
55 views

drizzle not updating events properly - duplicate events

I'm facing a peculiar problem while rendering event values in a component using drizzle. When a new event is created and is updated in the events array of drizzle (drizzleState.contracts.MyContract....
2
votes
0answers
237 views

using events in private blockchain raises leveldb not found error

i'm getting { [Error: Node error: {"code":-32000,"message":"leveldb: not found"}] when trying to use events on a private eth blockhain. What might be the problem? (I've installed Leveldb with brew) ...
2
votes
0answers
54 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
77 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
250 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
715 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
122 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
336 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
455 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
411 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
54 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
270 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
320 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
211 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
138 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
1k 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
237 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
298 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(...
1
vote
0answers
4 views

Do Graph queries have a maximum response size?

I'm running a Graph node for a personal project and I'm wondering if there is a defined maximum response size for queries. I see that pagination is an option according to the documentation, but it's ...
1
vote
0answers
15 views

How can i get the name of an emitted event through the event abi (log entry, topics) of solidity?

I want to get the name of an emitted event from my contract using the event abi and web3j. This is the contract i'm using as an example for this question: pragma solidity ^0.5.7; contract ...
1
vote
0answers
20 views

Ethereum transaction events listener with AWS lambda

We are using ERC20 tokens in our application for our transactions. We are having a hard time as to how to keep track of pending transactions and users token balance. Ideally, we want to notify user as ...
1
vote
0answers
39 views

How to watch/wait for events in JavaScript + Truffle?

I'm learning to develop Oracles, and, like all of us, I've encountered a dated article. After fixing all the Solidity changes (version, adding emit to fire an event, changing constructor function to ...
1
vote
1answer
63 views

How to use `topics` as an argument in `getPastEvents()`

I am currently attempting to collect data on token transfers. In order to accomplish this, I am collecting data using getPastEvents() and I am passing a filter object as an argument to collect ...
1
vote
1answer
29 views

Events declared in library are missed in contract ABI

DYDX contract SoloMargin is firing events like LogTrade, LogSell but they are not provided in ABI. SoloMargin contract: https://etherscan.io/address/0x1e0447b19bb6ecfdae1e4ae1694b0c3659614e4e#code ...
1
vote
0answers
46 views

Can not run more than 1 event in Infura

I am trying to listening to many events from infura but it is not working. Only one filter work, when I add the second filter, this message appear: RuntimeError: cannot call recv while another ...
1
vote
0answers
24 views

Events stop triggering after a while

I created a script that subscribes to PairCreated event on Uniswap using Web3 and Infura API. The event works for a few minutes but stops working after a while (timeouts?). How can I make it watch the ...
1
vote
1answer
212 views

ethers.js Why aren't logs filtering? (query returned more than 10000 results)

I'm building an API to scrape events from a contract suite deployed to Rinkeby. Here's an example function with some context: const network = getNetwork(parseInt(`${process.env.CHAIN_ID}`)); const ...
1
vote
1answer
25 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
34 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
1answer
136 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
16 views

get statistics by event filters or normal blockchain traversal

I want to ask what's the better approach among the following two: Filter events using address.eventFilter function or traversing the local blockchain block by block and getting events statistics. I ...
1
vote
0answers
12 views

Setting up listener using web3py

I'm setting up a proof of work contract. When a solution is found, the contract emits a Transfer event and the number that gets hashed with future solutions changes. I need to set up a listener so ...
1
vote
1answer
43 views

Storing name values off-chain in events and web3.js

Somewhere I read the advice to store name (title, geographical name, people name, etc.) value off-chain in events. But if a value is stored in an event, is there an efficient way to retrieve its ...
1
vote
0answers
68 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 ...