Questions tagged [web3js]
Javascript API and library for Ethereum To develop applications on Ethereum, you can use the web3 object provided by the web3.js library. Under the hood it communicates to a local node through RPC calls. web3.js works with any Ethereum node, which exposes an RPC layer. https://github.com/ethereum/wiki/wiki/JavaScript-API
1,746
questions with no upvoted or accepted answers
9
votes
4answers
2k views
Adding Wallet using web3.eth.accounts.wallet.add
On web3 0.20.1, I am using Infura to deploy a contract to Rinkeby. This probably requires me to add a wallet to web3.accounts to provide the gas needed.
When I ran the following nodejs code,
Web3 = ...
8
votes
1answer
983 views
getting started with geth and ENS commands: Error: invalid address
I'm starting from square zero, sorry. I'm just trying to get a javascript console up and running so that I can learn more about ENS:
http://docs.ens.domains/en/latest/userguide.html#resolving
I've ...
7
votes
0answers
133 views
How does estimation of gas price changes after implementation of EIP-1559
I understand that after EIP-1559 implementation, the fee structure changes to now have max priority fee and max fee instead of single gas price.
The question is though what could be the best strategy ...
6
votes
1answer
783 views
Problem with start() in web3-provider-engine
While trying to connect to a provider(infura) I get the above error below is the full stack trace:
bundle.js:54318 Uncaught TypeError: this.provider.sendAsync is not a function
at Web3Subprovider....
5
votes
1answer
513 views
Can't debug transactions that fail during the Web3.js estimateGas() call? No Tx Hash
NOTE: I am doing my work with the Ganache v1.2.2 GUI client on a Linux Ubuntu 18.04 station.
There are many revert errors that happen during the estimateGas() call that precedes the actual Web3.js ...
5
votes
1answer
650 views
web3.eth.getBlock returns null
I have a very similar problem as https://github.com/paritytech/parity-ethereum/issues/8788
When I use web3.eth.getBlock for the first 1 million and latest 50,000 blocks (approximately), I get the ...
5
votes
1answer
1k views
Call write function, which doesn't change contract value
I'm new in smart contracts and faced with one problem.
After deploying contract to my test local blockchain network, i try to set new value via setter, after that I call get method of contract and it ...
5
votes
2answers
525 views
How to access dynamic list from web3?
In my application players can create and join games. I store every game in a mapping(uint => Game), and send out a GameCreated event whenever a game is created. My issue is efficiently getting a list ...
5
votes
0answers
4k views
Use of web3.js batch requests
The web3.js API allows for synchronous RPC batch requests
with the example given as:
var batch = web3.createBatch();
batch.add(web3.eth.getBalance.request(
'...
5
votes
1answer
244 views
web3.eth.compile.solidity(source) throws me Invalid JSON RPC response
I am relatively new to Blockchains and when I execute the following command I am getting an error.
contract mortal {
address owner;
function mortal() {
owner = msg.sender;
}
...
4
votes
0answers
228 views
How to continuesly fork mainnet on latest block
How do I keep the fork mainnet use the latest block using web3?
I need to fork mainnet to latest block before I send the transaction
What originally i do is just run the ganache fork command which ...
4
votes
0answers
464 views
Unit testing a Solidity Library function with a struct memory argument
I am trying to unit test a Solidity Library contract function using truffle and web3. My simplified Library contract looks like this:
pragma solidity >=0.5.16;
pragma experimental ABIEncoderV2;
...
4
votes
0answers
319 views
How to get ethereumjs-abi's soliditySHA3 and web3 sign equivalents in ethersjs?
Hello I'd like to create a hash using ethersjs that encodes a number of arguments. I previously used ethereumjs-abi's soliditySHA3 function but not sure which of ethersjs crypto utilities is the ...
4
votes
0answers
393 views
Truffle test of two transactions during the same block
I'm trying to test a solidity function that only allows it to be called once per block. E.g. (my desired functionality):
Tx1 calls Fn during block #100, and when successful sets a boolean flag for ...
4
votes
0answers
321 views
How to access txpool pending transactions using Netherum?
I want to get list of transactions which are in pending state & queued state in txpool. I can see these transactions in pool using txpool.inspect command.
I tried code given in nethereum sample ...
4
votes
0answers
565 views
How to Catch Connection Issues to Web3 Provider using Web3.js
My node.js script is able to successfully connect to the Web3 provider when both the private key (using truffle-privatekey-provider) and the provider host URL are correct.
let privateKey = ...,
...
4
votes
0answers
119 views
Retrieve MetaMask version in web3.js
Is there a way to determine the version of the currently installed MetaMask extension from web3.js?
I can't find it by inspecting the Web3 instance.
4
votes
0answers
2k views
Mining hangs on Generating DAG in progress
I am trying to initialize rpc using the below command and start miner using miner.start(1);
geth --rpcapi eth,web3,personal --rpc --networkid=15
Mining starts successfully with below logs but it ...
4
votes
0answers
202 views
Estimated gas is always low
web3.eth.estimateGas is always calculating low gas for the transaction. Here is a reference to a trasaction in ropsten.
https://ropsten.etherscan.io/tx/...
4
votes
1answer
260 views
DEVp2p Wire Protocol tutorial on geth or Web3.js/Web3.py
I was looking to develop an application using ÐΞVp2p Wire Protocol and I'm having trouble finding an example or tutorial. I was able to find only ÐΞVp2p Wire Protocol's wiki.
[Q] Does anybody has a ...
4
votes
0answers
235 views
Is it possible to see the event log when using eth_call?
I want to perform a transaction locally (with the call method in web3 which perform a eth_call RPC call). It returns only the return value of the function called and I want to see the event log.
I ...
4
votes
0answers
248 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 ...
4
votes
0answers
669 views
How can I retrieve transaction hashes using web3 batch requests?
When I send a transaction using Truffle's contract wrappers - or using plain web3 sendTransaction() - I get a tx hash back that I can use to confirm the tx has completed. While using batch requests (...
4
votes
0answers
80 views
How to do a disaster recovery in private chains?
How can I do a disaster recovery on a private chain running ethereum, say for instance Quorum ?
4
votes
3answers
2k views
Correctly deploying contracts with web3 1.0 and testrpc (invalid opcode error)
I followed the following tutorial:
https://medium.com/@mvmurthy/full-stack-hello-world-voting-ethereum-dapp-tutorial-part-1-40d2d0d807c2
Now this tutorial is not using the recent version of web3 but ...
4
votes
0answers
231 views
how to get revert at the previous timestamp of evm in testrpc
I am testing my contracts so at some point i need to increase the timestamp of evm that i achieve through evm_timeIncrease but now i want to execute some functions on the basis of current timestamp ...
4
votes
2answers
958 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
2answers
1k views
Importing a contract from another contract in NodeJS app
I'm using a function in my NodeJS app to deploy contracts. The user inputs the contract he wishes to deploy and the app deploys it. The structure of the app is
.
├── app
│ ├── models
│ │ └── ...
4
votes
0answers
356 views
Contract execution fails with Web3 but works with Remix
I am dealing with a very simple smart contract:
contract MyRegistry {
struct MyEvent {
string date; // yyyy/mm/dd
string desc; // potentially long string
uint count; // &...
4
votes
0answers
401 views
How to create my own wallet and own blockchain explorer?
I'm running my own private/permissioned ethereum blockchain via geth on Ubuntu. How can i interact with my blockchain to visualize accounts, blocks, transactions etc...?
I've tried a lot of tutorials ...
3
votes
0answers
431 views
Can gas price and amount of gas be automatically set by metamask, or are they required to be set via code in web3.js (EIP-1559)?
I am using web3.eth.Contract to deploy a smart contract to the ropsten testnet. To interact with metamask I am using window.ethereum. I deploy the contract via the code below that I found on https://...
3
votes
0answers
574 views
How to create a wallet with web3.js
From what I understand, a wallet is a smart contract and in order to create a wallet, you need to deploy the contract to the blockchain as stated here, which is different from creating accounts.
When ...
3
votes
0answers
305 views
geth javascript console: web3.eth.subscribe ==> "Object has no member 'subscribe'"
I must be missing something -- I am trying to use the web3.eth.subscribe() function in my geth node's javascript console and there is no subscribe function.
Welcome to the Geth JavaScript console!
...
3
votes
0answers
2k views
Swap tokens to Ether on Uniswap V2 TRANSFER_FROM_FAILED
I am trying to swap DAI to ETH on kovan testnet my wallet and contract both have DAI tokens. Whenever I swap the token through web3 the transaction fails Fail with error 'TransferHelper: ...
3
votes
0answers
2k views
Contract call: data out of bounds
I'm working on a nextjs/react project in which i want to fetch the health factor of an address on AAVE. This can be done by calling getUserAcountData(address) on the lending pool contract. I can ...
3
votes
3answers
8k views
How to disconnect MetaMask wallet using Web3modal
I am using metamask with kovan to connect to the wallet
import React, { useState, useEffect} from 'react';
import Web3 from "web3";
import Web3Modal from "web3modal";
import Navbar from './components/...
3
votes
2answers
91 views
Auction contract problem regarding highest bid display
I have an Auction contract which has a function like this:
function bid() payable{
//calculate and store highest bid value
}
But because each transaction takes time to mine, so when a user bids ...
3
votes
1answer
70 views
What is the best way to push transactions with hight rate (>1000 per second)?
In order to test the throughput of a private Ethereum, I need to send multiple transactions as fast as possible. Can web3js ensures fast delivery of transactions? or there is an other more efficient ...
3
votes
0answers
7k views
Get RPC URL / IP of Metamask's current provider
Suppose I have multiple copies of the same dapp running on different servers which do not directly communicate with each other, for testing purposes, and can manually interact with different dapp ...
3
votes
0answers
119 views
Invalid JSON RPC response on IOS build with Infura
I am developing a mobile DAPP using ionic frame work, everything was fine when I testing on the browser. However I try to build my app on IOS, and run it on my Iphone7, the web3 doesn't work(did't ...
3
votes
0answers
46 views
Most efficient way to get all non-zero storage locations for a smart contract?
I'm looking at a mainnet smart contract and want to figure out all storage positions/slots where the storage has a non-zero value.
Is there a way to do this other than replaying and tracing all ...
3
votes
0answers
561 views
Why can't I fetch my Metamask account address with Next.js's getInitialProps?
I'm using Next.js to implement server-side rendering in my Ethereum app, however I can't fetch my Metamask address to display it in the top-right corner of the navigation bar in my index.js file. ...
3
votes
1answer
206 views
Web3JS incorrect return value
When I return a string array with web3 I don't get the original array as expected, but rather I get an array of the same size, with the index off by one.
So instead of ["One","Two","Three"] I get ["",...
3
votes
0answers
151 views
Quorum :- metamask do not support privateFor feature of quorum
i got to know that metamask do not support privateFor because of which private transaction for quorum dapp was not behaving as expected. so, I can't use metamask for my quorum DApp to switch port and ...
3
votes
0answers
1k views
NetworkError when attempting to fetch resource. Resource URL: moz-extension://2.../contentscript.js Source Map URL: ../sourcemaps/contentscript.js.map
I get the following error message in Firefox Developer Tools Console following a successful sendTransaction:
"Source map error: TypeError: NetworkError when attempting to fetch
resource. ...
3
votes
1answer
331 views
Create Accounts Using Web3.js in Browser
TL;DR - Replicated Ethereum Blockchain. Running Local Node. Connecting Local Node to Web3.js in browser using RPC. Want to create addresses & send transactions
Details -
I have a blockchain that ...
3
votes
1answer
1k views
Recover address from signature using web3j
I have signed a data string using the following code snippet in web3js
var data = "hello world";
web3.personal.sign(web3.fromUtf8(data), web3.eth.accounts[0], function(error, result) {
if (!...
3
votes
0answers
273 views
Error:new bignumber() not a base 16 number
I have built a private chain with two node on two computer. The smart contract was successfully deployed on node1,and i can call the method on node1 ,but when i call the same method on node2,it occur ...
3
votes
0answers
739 views
web3.eth.sendSignedTransaction - transaction not located
I am using web3.eth.sendSignedTransaction and infura.io on mainnet. I want to call my smart contract's whitelisting function. I have no problems calling this function directly, however, when using ...
3
votes
1answer
1k views
ERC223 Token Fallback Function Usage
I'm currently writing the "Trade" smart contract which is similar to "Crowdsale" smart contract. The only function that I want to add is "sell" function. In general Crowdsale smart contract is used ...
