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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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1answer
51 views

A common error at time of using web3 options

When i use some web3 options as follows, I receive a common error i.e. TypeError: web3.[option] is not a function For example : TypeError: web3.toAscii is not a function web3.toAscii(...
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1answer
34 views

Web3 event listener - timing issue when immediately retrieving contract values

I'd like to be able to immediately get a struct value from a mapping after calling a function that updates the struct, however, when testing with Ganache, sometimes the event arrives to the listener ...
2
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1answer
43 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....
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1answer
55 views

Error trying to get events in web3.py via Infura

I was trying to get all events from my smart contract (in Ropsten) via Infura node. The problem is that I know that Infura does no support creating filters, but I don't know how to get events by ...
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1answer
55 views

Why raise a Created event in a Smart Contract constructor?

Reading through the Bancor code I see this: function SmartToken(string _name, string _symbol, uint8 _decimals) public ERC20Token(_name, _symbol, _decimals) { NewSmartToken(address(this)); ...
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1answer
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In node.js event is not fired

I am using web socket to get event. sending transaction works fine. but event is not fired. also I referred Web3 events not working but it does not work, too. I used eventemitter also. but it did ...
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2answers
1k views

Truffle test, logs do not include an emitted event

I am calling a contract function which emits an event in a transaction. This transaction should include the event and is typically visible via: const receipt = await contractInstance.someFunction() ...
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0answers
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How do I get the value from the event to be displayed on the webpage? [duplicate]

I can connect and console.log the event. But can't bring the value to display on the webpage. I don't know what to do. Front-end import React from 'react'; import logo from './logo.svg'; import './...
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2answers
576 views

Does Etherscan store all the events and transaction history?

To get the history of a transactions for an account, we have to traverse the whole chain everytime, but etherscan provides the entire history of all the accounts instantly. Similarly it does the same ...
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1answer
58 views

What data is in 'calldataload'?

I want to parse event logs that are generated by the contract shown below, which assigns different sections of calldataload to the 4 Topics, and the Data section, of the event logs. Topic 0 receives ...
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1answer
16 views

Event propagation from imported contracts

Im implementing a contract with imported subcontracts of my own. I'm trying to understand if I can receive the events emitted by the imported contracts, but since contracts can be inherit other ones ...
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1answer
30 views

List of ALL Ethereum Contract Events, for ex: Transfer, Mint, etc

A very simple question, yet couldn't find a simple answer. Where can I find a list of all event types such as Transfer, Mint, etc? Is this stored anywhere, for ex: online database or historically ...
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2answers
53 views

dYdX event log signature hash

dYdX has an event called LogDeposit(address indexed accountOwner, uint256 accountNumber, uint256 market, BalanceUpdate update, address from) within their SoloMargin contract. I am trying to get the ...
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1answer
136 views

How to listen contract event in Python

The test contract is pragma solidity ^0.5.0; contract Test{ event Here(uint256 indexed a); uint256 public a; function add() public returns (uint256){ a += 1; emit Here(...
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1answer
69 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 ...
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1answer
155 views

About getPastLogs usage

"getPastLogs" can get past event log. I check the web3 documentation: fromBlock - Number|String: The number of the earliest block ("latest" may be given to mean the most recent and "pending" ...
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0answers
444 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: '...
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1answer
3k views

Current methods to send encrypted messages from contracts

I am trying to understand if there currently exists a method to send a message from a contract to another contract or a private address? What would the Solidity code for this look like? Perhaps events ...
5
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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 ...
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3answers
1k views

How to get events emitted by a transaction with web3.js

I'm writing a user interface in Javascript and I'm using the web3.js library. I have the transaction hash of a confirmed transaction. I would like to get an array of all events emitted by that ...
17
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3answers
4k views

How to check events in Truffle Tests?

What's the best way to check that events were fired in a Truffle test?
2
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1answer
176 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 ...
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0answers
5 views

Nethreum CreateFilterInput Block Number boundary issue

I obtained the latest block number by using: var Latest = web3.Eth.Blocks.GetBlockNumber.SendRequestAsync().Result; Assume Latest = 400000 I create a filter even from block number 390000 to (the ...
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1answer
35 views

Event Names not showing up on Etherscan

For some reason Event Names associated with transactions to my contracts aren't being shown in their Event Logs on Etherscan. Worth noting, this event in particular is not indexed. Any thoughts as to ...
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3answers
425 views

Not able to export to csv all transfer events of a specific contract on Ethplorer.io

I'm able to use the Export to csv function, but it's only giving me the most recent 1000 events. Any suggestions on how to get ALL (2100+) of the events in a csv file? https://ethplorer.io/address/...
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1answer
114 views

Is it possible to have indexed bytes32 argument in an event?

I have an event with two indexed arguments orderId and status. Filtering works fine when I filter the event on orderId which is uint. I am not able to filter the events on the second argument (status)...
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1answer
81 views

Can not see Solidity events

I can see events in a private net, but when I connect to "real" net, I can not see them. Meaning .watch(function(err, result) is never called. My theory is I am using lightning, and it probably means ...
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0answers
61 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 ...
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1answer
24 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 ...
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2answers
247 views

Solidity event function not appearing in web3

I have a contract with the following event (using 0.4.24): event UpdateProgress(bool _gameInProgress); I am registering the contract like this: import Web3 from 'web3'; import address from './...
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3answers
123 views

Reading the result of a function that change state by using events in Solidity

I would like to get the result of a function by listening its emitted event. These are two pieces of code of my contrats CONTRACT 1: function createTradeableContract() public stopInEmergency ...
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1answer
29 views

TypeError: market.FileViewed is not a function while trying to watch event

I want to watch for fileViewed event and it throws TypeError: market.FileViewed is not a function in marketplace.FileViewed{ ^ My solidity contract: pragma solidity ^0.5.0; contract ...
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0answers
27 views

getPastEvents undefined(please help)

I had asked this question before. I looked carefully at the exchange section, which I advised, and I think there is no problem with the exchange section. At least in my opinion there is no problem and ...
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1answer
121 views

Solidity triggered event that shows a message to everyone who is currently in the site

Just a small question regarding how solidity event works. Let's say I have a function buyCandy(). At the end of the function I attached event: emit LogBuyCandy(msg.sender); event LogBuyCandy(address ...
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1answer
268 views

Web3.js event.get not firing, whereas event.watch gives correct values

I am trying to do a simple test for events. Following is solidity code. Values received from chgEvent.watch are always correct. But in chgEvent.get, results1 is empty. chgEvent.get does not get ...
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1answer
214 views

How to stop listening to all events of contract

I am using the JavaScript API in my truffle tests to get the events from the contract: https://github.com/ethereum/wiki/wiki/JavaScript-API#contract-allevents const allEvents = instance....
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1answer
159 views

Iterating through events

I have events (fired some time ago by the contract) containing numbers. I need to load them all, and then to draw a chart. What I do: contract.getInitBlock(function(error, value) { var ...
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1answer
195 views

Filters object not working for web3.eth.contract getPastEvents() method

I have referred, Web3 Events, but filters object is not working for me, I've got the same result for events before and after applying filter object. Here's the code: instance.getPastEvents( "...
1
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1answer
214 views

Event unique identifier

The web3.js (1.0) docs helpfully list the return values from a contract event subscription. I've noticed that there is an additional return value id that isn't listed there but is returned with the ...
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0answers
21 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 ...
3
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0answers
230 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....
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0answers
58 views

Events using Infura websockets on rinkeby Web3 1.2.1. Returned values aren't valid, did it run Out of Gas?

I am trying to do a simple event listener with NodeJS and Web3 using an Infura endpoint. I have the correct project-id const Web3 = require('web3'); let web3 = new Web3( // Replace YOUR-PROJECT-ID ...
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1answer
134 views

Watching for events returns 0 blocknumber

I am trying to listen for recently mined events from a live smartcontract(EtherDelta). //https://github.com/praneethmendu/ethualizer/blob/master/backnd.js tradeEvent = contractIns.Trade(...
2
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1answer
196 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 ...
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1answer
142 views

How do I watch Events from multiple contracts

I wrote a script that is able to read events from one contract address and then paste it into a .csv. Now I would like to extend that script listening watching/reading the same event of several ...
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1answer
31 views

Way to create an event?

As soon as a function is called this other function should also be called!! Example: As soon as ether is deposited it should transfer funds into employees wallet. I already have functions deposit() ...
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1answer
34 views

Emited Solidity Events not being watched at frontend truffle contract instance

So, I have been reading through A LOT of pages about events in Solidity and how to interact with them on frontend but I am still pretty new to this and it seems like there have been multiple changes, ...
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1answer
312 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 ...
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1answer
20 views

If for each setter I can get the blockchain state at the moment and make it queryable, will I still need events?

That question came as part of understanding better the role of events in Ethereum. Can the mechanism which index the blockchain state at each setter and makes it queryable for all parties can ...
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1answer
171 views

Remote geth node failing to retrieve past events

I have set up a remote geth node on AWS as a web3 provider for my DApp. The geth node is initialized with the following command (for testnet) as a daemon service: [Unit] Description=Ethereum go ...