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.
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What do the to/from fields in a swap event mean?
Im parsing swap log events from web3 and was reading the to and from addresses from the topic but sometimes the from/to address is the same, and other times its different. It doesn't seem to ever be ...
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Python Event Listener
I am trying to listen events from smart contract from python backend offchain code part.
I tried different code parts such as below where MemberAdded is the name of the Solidity event.
event_filter ...
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Not able to dynamically assign values to array
I am testing the correct emission of NFTMintedAll event on the following function, using hardhat:
event NFTMintedAll(
uint256 requestId,
address indexed owner,
uint256[] ...
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How do you "fake" the signature of a Solidity event?
The Note for the official Solidity documentation on Events says that "it is possible to “fake” the signature of another event using an anonymous event", without going into details of the ...
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Is it possible to know if a NFT was sold in OpenSea?
Is it possible to detect, by looking at the transfer events, whether a NFT was sold from a Marketplace or not?
Basically I want to know if, in these cases, the safeTransferFrom method notifies the ...
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Listen to transfer event on any ERC721 compliant contract (ethers.rs)
I am trying to make a program that, given a ERC721 contract address, will listen to all transfer events done on this contract until a certain point. I am not yet very familiar with how Ethereum works, ...
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Can't catch all the events using ethers
Can't catch all the events. Why?
I try to listen to events for several contracts and it is ok. But the more contracts I listen to, the more events are missed? Is there any way to prevent this and why ...
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Scalable way to listen dynamically added contracts in web3j
Consider I need to listen to the event logs for a Uniswap's Swap method, which works perfect for a single CA, or even to many if they are known to the time of creation of filter:
web3j.ethLogFlowable(...
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WEBSOCKETS Provider url for binance smart chain
I have a contract deployed in Binance smart chain. I have written a script that will help me read the events logs from the Blockchain. currently, I tested that with the local hardhat network itself, ...
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Reading events from layer 2 blockchains
I'm planning to query a tx using a tx hash on Ethereum and get the events/logs to find out the recipient and sender of the ETH.
Is it possible to do so for L2 blockchains like Optimism, ZkSync, ...
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FilterException when creating an EthFilter in web3j
I'm using web3j to create a filter to listen to events.
Specifically, I want to listen to events of a specific contract between a certain block number and now.
This is my code:
Web3j web3j = ...
...
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Why is Alchemy eth_getLogs not finding event logs for AaveV3 Supply events?
I have created a Node project that connects to Alchemy via ethers. I am trying to capture all Supply events for AaveV3
However, when I use the getLogs function, and use the contract address as the ...
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before all" hook for "should allow a purchase" error - Chainshot
I am completing series of tutorials on chainshot. Now I am on events 4. - Sale and I am getting an error
"before all" hook for "should allow a purchase"
and I don't have an idea ...
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How can I decode the emitted event data field using Foundry Cast in Ethereum?
I'm trying to extract relevant information from the event but I'm not sure how to decode the emitted event data using cast. Any tips or resources would be greatly appreciated. Thank you!"
E.g for ...
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What is wrong with this function that is supposed to listen to an event from a smart contract?
I am essentially just trying to create a simple API that listens to this one event on a smart contract I created but for some reason the function doesn't output anything. I am pretty sure it has ...
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Etherjs "contract.on" method in Reactjs to read events not loading on console
I am trying to display the events that are emitted from a function in my smart contract to the front end of my dApp, and I feel like I am missing a step in the connection process with my dApp.
I've ...
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If no event is triggered with normal transaction, how do one listen to "transfer activities"?
This question is a follow up question based on the answer I got to the question How many transfer events are there in Ethereum?
The answer mentioned that:
There is no event emitted when an account ...
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Is it possible to track marketplace sales for an ERC721?
I know I can track events for smart contracts, such as Transfer and Approval for ERC20 and ERC721 or even ApprovalForAll for ERC721.
I also know that I can track my own defined events for any smart ...
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Why do events with arguments of custom types appear fully-encoded in Tx Logs?
You can observe the behavior via the following contract which I've deployed to Polygon Mumbai at 0x33c059160280a45725d9509c120c6b30a44a61a4:
pragma solidity ^0.8.19;
contract EventWithCustomTypeArg
{
...
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ERC20 - Approve/TransferFrom vs listening to Transfer events
I've been learning about the ERC20 standard and I've seen in several places statements like
If a smart contract want to detect when it receives a transfer of ERC20 tokens the standard approach is for ...
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TrroubleShooting "events" (event.arg) with smart contracts, ethers js, and deploy scripts?
I am getting the following error message in regards to my script below. Please keep in mind the deploy scripts have already been successfully run and the addresses successfully exported and saved in ...
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How does an event listener work in real time?
My frontend is watching/listening for a contract event. When an event is emitted after the contract is called, how is a listener notified in real time? If it is done through JSON-RPC polling using ...
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Problem with recognizing an event (testing)
I'm doing this as a part of a solidity course by Free code camp (PatrickAlphaC). Here is my repo:
https://github.com/Sosiaalinen/Raffle
In my understanding, it should recognize the event, since it's ...
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Is eth_subscribe always sending logs in the right order
I am using eth_subscribe to log for all token transfer events that are happening on the blockchain.
Here is my code:
import asyncio
import json
from secret_config import RPC_ENDPOINT
from websockets ...
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How can I retrieve the event emitted from a function call of another contract?
I notice when I have a function calling another function from another contract, the events emitted aren't captured by ethersjs. In my case, I want to retrieve the event emitted from ContractA even ...
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Is it 100% guaranteed that a process that listens to blockchain events will receive them if they get emitted?
When a smart contract emits an event, if I am listening to them for example with an application that stores all events from that smart contract into a database, do I have the certainty that I won't ...
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Library package helps interact with Blockchain on the Ethereum platform (ETH, BSC, Polygon...) more simple and minimized
I am a Blockchain engineer and after 3 years of working with the EVM-platform I used many different libraries such as web3, ethers, ethereumjs-tx,... I realized they are so distributed and complex to ...
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Is it possible to set up an event listener that will catch all ERC20 tokens
Is it possible to set up an event listener in such a way that it will trigger for all token transfers?
I am using web3.rs at the moment which is an implementation of web3.js in Rust. So anything that ...
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When should a protocol should emit an event?
I understand that a protocol can emit events for any of the following reasons:
Make it easier to do a data migration in the future (ie, copy-pasting storage mappings is much easier with events)
Store ...
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Getting the value of a event topic with Go ethereum [duplicate]
I have an event that has two indexed arguments, a uint256 and a string.
I am successfully able to get the Hex value of the event topics i am looking for but I am having trouble to decode the string ...
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Decoding logs of Approval event with web3js results in error
I am trying to decode the Approval event of an ERC721 contract.
I fetch the logs for the contract with the alchemy API and then try to decode them
with web3js.
The code looks like this:
const logs = ...
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How to parse event args: struct of custom internalType
Question: How does one parse the contents of a custom struct emitted as an indexed parameter with a contract event? Or, is it even possible to emit and then parse a custom struct from the event args?
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Get ABI code for an ethereum contract event
How can I construct the ABI code for a contract event?
I don't need the whole contract ABI.
Example:
transferFrom(address,address,uint256)
executeMetaTransaction(address,bytes,bytes32,bytes32,uint8)
...
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Uncaught (in promise) TypeError: ProposalsRegistrationEndedEvent.watch is not a function
I was following an old Ethereum dapp tutorial to make a voting dapp. It uses truffle contract, web3js and ganache and when i access the pages via localhost i get the following error in the console: ...
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Accessing the network throught light sync node
I'm trying to create an application that will track balance changes at specified addresses. I want to catch new block validation events and see if there are transactions associated with my addresses. ...
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1
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Subgraph indexing error, mapping aborted with ethereum value is not an address
Subgraph indexing failing due to mapping abortion with reason - ethereum value is not an address, from one of the handlers. I understand the issue if from the handlePaymentExpenseCreated() function ...
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1
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Reading and listening to Solidity events via Web3.py and websocket
Recently I have been solving a problem of how to listen to and read Solidity events in Web3.py via websocket rather than constant HTTP calling.
You may be familiar with this algorythm which can be ...
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Retrive data from chainlink node
in APIConsumer contract on chainlink docs (Any API)
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.7;
import "@chainlink/contracts/src/v0.8/ChainlinkClient.sol";
import "@...
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Does Hardhat node not support emitting events?
So I am running this code that is the standard code for logging events to the ReactJS App UI, but I cannot understand why it does not work. I am not getting any errors either.
import React, { useState ...
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Could not find corresponding event log from 0x aggregator contract
Looking at the event log from the 0x Protocol aggregator contract ("0xdef1c0ded9bec7f1a1670819833240f027b25eff"), I could not find corresponding event to the following log topics0 "...
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Listening to multiple smart contracts
Is there an "optimal" way to listen to multiple smart contracts?
For example, listening to an event emitted by one smart contract in a useEffect:
useEffect(() => {
const ...
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web3.eth.subscribe not working properly
import Web3 from "web3";
const web3 = new Web3(new Web3.providers.WebsocketProvider("url"));
const addr = web3.utils.toChecksumAddress("...
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Number of events in Solidity code vs on Etherscan
Hey guys I have a simple Solidity code, which emits events shown in the code bellow.
What I don't understand however is that on Etherscan I get many sections with events that I have never coded. Why ...
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Solidity Events are not emitting properly, even with the successfull transaction!
Solidity Events are not emitting properly.
This is the code "Nftfactory.sol":
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "../MPContractFactory/Interfaces/...
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Web3.js event listener keeps reconnecting
I have a websocket set up listening to an event of a particular contract. However, I have noticed that the .on('connect') event keeps getting triggered intermittently leading me to believe that I am ...
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Same event triggering action more than once using useEffect and Ethers.js
I am trying to listen to a smart contract event, but my event listener is getting triggered more than once per event.
The event is being emitted and returns two strings. The event is declared as event ...
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Replace storage with the use of events. Considerations, risks?
I'm testing to not use state variables and relay on events and an external service to know the latest state and history of, in the simple example above, a Document. You can think about Document as a ...
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How to track for certain all addresses affected by a transaction?
So I am asking this question because I recently learnt about what is called "Internal Transactions". I was actually reading the answer here and from this I understand that a transaction ...
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How can I parse an Ethereum block-level logsBloom?
I have been downloading blocks from EVM-based blockchains via the JSON-RPC API via eth_getBlockByNumber. In the block there is a logsBloom element which, if I understand this correctly, is an ...
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Problems reading emitted events with string data with ethers.js
I have a smart contract that produces NFTs and emits an event when contract is created.
The definition of the event is:
event NewBKNFT(address indexed contractAddress, address indexed publisherAddress,...
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