Questions tagged [ethereumjs]

For questions regarding the installation or use of EthereumJS, a Javascript library that implements a number of Ethereum utility functions.

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20 views

How to parse ecrecover parameters?

I am looking into getting the public key from ANY ethereum address (not owned by me) that has sent a transaction at least once. It seems that the most viable solution here would be to use ethereumjs-...
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17 views

ethereum hash is not searchable in parity private network

I did this in rospten network, but when I use it in private parity network, I get transaction hash, but it isn't searchable at the explorer: const Web3 = require('web3'); const EthereumTx = require('...
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2answers
34 views

I Call SmartContract Token ERC20, Why Show Hashing Output ? (Web3 + Metamask + Javascript)

I do not know why with this, even though in the previous version (web3 + Metamask) can issue real data. But now used as hashing (output). I took the example in the code and output below (to get the ...
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3answers
60 views

How to build a decentralised Voting Website without using any 3rd party extensions like Metamask, or IDEs like Remix? [closed]

I've gone through various Blockchain Tutorials but everywhere it's one or the other same thing. Download truffle/ganache, from 10 free testrpc account, use one, use metamask, Remix IDE etc, and Voila!...
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39 views

Transactions go to an older contract address rather than the present deployed one

Though I have deployed a new contract but the transactions go to a previously deployed contract in my application. I'm attaching the screenshot of my Remix-ide code and the code for the front end ...
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1answer
99 views

problem connecting web3 v 1.2.1 with metamask : 'currentProvider' of undefined

I am using Web3 v1.2.1 with nodejs v10 and following this link. I am having issue connecting with metamask,below is my code snippet: const Web3 = require('web3') const window = require('window'); ...
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1answer
24 views

Code:const web3 = new Web3(window.web3.currentProvider) Error: window.web3 is undefined

I am going to connect my contract with the website.However,there was something wrong with the web3? I'm not sure. import Web3 from "web3"; const web3 = new Web3(window.web3.currentProvider); const ...
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1answer
56 views

Which version of web3 shall i be using now?

I found the documentation of version 1.0.0 which was released on the 6th of August here. I was told that v1 is not stable and very different than earlier versions. But when i check the available ...
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3answers
39 views

transferFrom function not working in ICO Smart contract

I am facing issues with the transferFrom function of smart contract address 0x6560a9b6436e129cf835ab9da96201207facd4f8: I copied the smart contract code from etherscan.io and deployed on ropsten ...
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1answer
42 views

How do I use web3js 1.0.0 in geth 1.9.0? I want to import an account whose address, private key and passphrase I have in my geth node [duplicate]

I am at Geth/v1.9.0-stable-52f24617/linux-amd64/go1.11.5 web3JS version is giving : > web3.version { api: "0.20.1", ethereum: "0x2712", network: "4", node: "Geth/v1.9.0-stable-52f24617/...
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22 views

Error: Keystore: Must include seedPhrase in createVault inputs. How to fix?

i'm studying blockchain development, and i'm trying to create wallet with seed words using eth-lightwallet and vuejs. But i receive this error: Keystore: Must include seedPhrase in createVault inputs, ...
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22 views

What is the difference between signing a document, signing a transaction and signing a message? (very basic)

As per my limited knowledge in Ethereum, user can sign the object(doc, Tx, msg) for the security purpose and with the public key other user can get that object. But not understand the difference ...
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30 views

How do I perform a fully anonymous transaction using Stealth addresses in Aztec protocol?

I want to know how to make use of Aztec's stealth address protocol.
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16 views

Can I Create Node.js API for each function in Smart Contract but sign a Transaction from frontend via Metamask.?

I am trying to develop a Dapp with nodejs backend but I cannot get accounts from Metamask which resides on my frontend. I tried to create an endpoint for each function in Smart Contract. And it seems ...
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1answer
26 views

How to know in advance the gas used by a transaction?

I want to send an ERC20 token (Ropsten network). So I execute a function 'transfer' on a contract. When The transaction is sent, I can get the gas used in the receipt. Few months ago this amount was ...
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0answers
15 views

Is there a way to broadcast/send transaction using web3js using token that is not ethereum?

My question is: I am trying to send a transaction using a cryptocurrency very similar to ethereum, in fact their code is almost copy pasted from ethereumjs: https://github.com/CSEPlatform/cse-tx/blob/...
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1answer
59 views

'ALERT: Trying to call a function on a non-contract address' Why Do I Keeping This Error?

This is the error from metamask directly: This is the error I get once after I submit the information to IPFS: My Smart Contract: pragma solidity 0.5.3; //Imports for safe math operations import "...
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1answer
27 views

Why txHash in sendSignedTransaction giving Undefined value on sending on rinkeby testnet

let Tx= require('ethereumjs-tx').Transaction; const Web3= require('web3'); const url='https://rinkeby.infura.io/v3/d4dbc79ea192404fb42689cc55ce2fc0'; const web3 =new Web3(url); const account1= '...
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0answers
24 views

Error using drizzle and react

My contract Storage.sol - pragma solidity ^0.5.0; contract Storage { string public data; function getData() view external returns(string memory) { return data; } function setData(...
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0answers
13 views

Error send token

let minABI = [ // transfer { "constant": false, "inputs": [ { "name": "_to", "type": "address" ...
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14 views

How to save contract address to database with web3js and mongoose when I deploying a contract?

I wanted to get my contract address after it deployed, and then save it into my mongoDB. But instead of that, my contract address is deployed after it. So my mongoDB won't save my contract address. ...
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0answers
30 views

which is a better method to use for signing messages between two parties in web3?

I have been searching for a while for the most secure and supported way for off-chain channel messaging.....so i was using web3.eth.sign(address, keccak256(msg)) for singing messages ....but then used ...
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1answer
64 views

How to use window function in controller (node.js)?

So this is my users controller to upload a file : exports.postUploadFile = (req, res, next) => { var ethereumURI = req.body.ethereumURI; var abi = JSON.parse(req.body.abi); var ...
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1answer
83 views

Error when testing the contract

ApprovalContract.sol pragma solidity ^0.5.1; contract ApprovalContract{ address public sender; address payable public reciever; address public constant approver=...
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1answer
26 views

Do smart-contracts work as APIs?

Is it possible to put a smart contract "behind" a restful API, i.e. expose my contract functions and properties through restuful API where I can make RPC to it? Or does it work as an API already, but ...
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3answers
139 views

comparing two addresses

I'am trying to create a modifier that allows certain accounts to execute functions. address[] authorized; function verify (address adrs) internal view returns (bool) { bool exist; ...
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1answer
37 views

ENS name reverse is not working on Ethereum address

I'm trying to both resolve and lookup using "ethjs-ens" the lookup call is working correctly. However, the resolve call is throwing an empty error. The address I'm using on the reverse function is ...
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2answers
30 views

Troubleshooting a revert on Ropsten

I’ve deployed a contract to Ropsten and am testing it manually with Remix. This transaction reverts for whatever reason (we have unit tests where everything looks fine). In our contract for all of ...
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2answers
35 views

Contract.deployed() does not work as expected

I use Truffle to test a contract. When i use Contract.deployed() and i fetch address, for example : In a first test, the contract's address is 0x07D899846146b3503dE9D9Dc36B94C2e428eA434 In a second ...
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0answers
11 views

Oraclize : Calling more than one API independently [duplicate]

There are 2 API 's which has to be called in different time delays recursively. For example : API_1 = 20 mins delay and API_2 = 24 hr delay. How can we call the above 2 API's independently based on ...
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0answers
13 views

Oraclize ethereum bridge : Notifying __callback tx error to frontend

I have called API dynamically using Oraclize with the delay of 10 minutes. The code is shown below and it works well. uint256 constant DELAY = 60*10; event Log(string result); function ...
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1answer
52 views

where does the metamask fits in Dapps architecture?

i am learning building Dapps. And i got to know to know about metamask. I've read about metamask is an ethereum wallet which we can use to sign Tx's without running a full node and inject web3 to ...
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2answers
41 views

Cannot declare web3 object in JavaScript

When I try to declare a web3 object It's always undefined. I'm writting in JavaScript and using Infura as my provider for the ETH mainnet. I also tried with a local blockchain instead of Infura, but ...
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1answer
52 views

How to call setter method of smart contract with web3 1.0.0

I don't know why but i'm not able to perform transaction with this code. please help me out i'm stuck. i just have to call setter method of my contract with some arguments. router.post("/set", async ...
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0answers
24 views

Web3js v0.20.7 - callback ls not a function

I'm facing issue of callback is not a function in web3js 0.20.7 when i call the method of sendRawTransaction to deploy smart contract with web3. When i used the same method just to call deployed ...
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1answer
66 views

How to use bip39 module in angular?

I am trying to create an ethereum wallet app using Ionic. I have tried to import bip39 node module directly in the angular project but it gives me error. Please help import { Injectable } from '@...
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1answer
22 views

connecting geth to web3.go 1.0 via websockets or HTTP

Is there anyThing similar to web3.js written in go that allows me to communicate with the geth client ?
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0answers
24 views

How to do loop all the metamask Accounts loop and display data from that address in React frontend + Dapp App JS [duplicate]

I want to Display data stored on the Ropsten Network in more then 2 metamask accounts. I want to display the result on the Home page in the table form. For that I need to loop through each ...
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1answer
39 views

how do etherscan get all the token balance of particular address?

I want to create service where just by providing address i can fetch all the token (erc 20 & erc721) balance just like etherscan for a private network? is there any way to do it by writing for ...
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1answer
114 views

How to deploy Smart Contracts With Web3 Using Async/Await?

This is my Javascript code. I keep getting an error that states Error: No privateKey given to the TransactionSigner. at TransactionSigner._callee$ (/Users/payton/WebstormProjects/Esgro_DAPP/...
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0answers
62 views

Web3 Websocket Connection To Infura Rinkeby Ropsten

This is my Javascript code. I keep getting an error that states (node:30062) UnhandledPromiseRejectionWarning: TypeError: privateKey.startsWith is not a function I am using node 12.1.0 & ...
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1answer
47 views

How to create a private ethereum network [closed]

I want to understand how to create a private blockchain using ethereum and create a minable coin. Also, I want to know if I can modify the consensus algorithm that runs on every node? There are ...
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1answer
101 views

Why Could not find artifacts for contract from any sources

I am using windows 10 with truffle and ganache-cli. I have 2 contracts file to be deployed contain interfaces of other contracts defined within the contract: Contracts: ERC721Mintable.sol Ownable ...
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1answer
234 views

Web3 - Cannot read property 'clearSubscriptions' of undefined

While creating a web3 instance, and attempting to call setProvider with a valid provider (Ganache), I get a TypeError. TypeError: Cannot read property 'clearSubscriptions' of undefined Steps to ...
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1answer
60 views

How do I deposit Ether to Smart Contract using Web3.js

So I am creating a web application that interacts with a smart contract that I deployed on the Ropsten TestNet. I am able to withdraw ether from the contract to my Metamask account using a withdraw ...
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0answers
26 views

getting an error while deploying smart contract of ethereum

I am getting an error while trying to deploy smart contract of voting dapp on ethereum I have searched for the solution for the same and i got a question with same problem but there no solution. ...
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2answers
447 views

How to connect with public Ethereum Blockchain on a backend/web server?

In the backend of a Web application I have to communicate with the public Ethereum Blockchain. On local development machine, I run ganache as testrpc and connect with such a line of code: web3 = new ...
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0answers
47 views

How can I comparing fingerprint using solidity language?

I have a fingerprint image stored in IPFS and I want to compare with another fingerprint image, because i need to know if is the same fingerprint ,is there some way, some lib that i can compare this ...
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1answer
57 views

Can I create & run test cases for smart contract without truffle?How?

does truffle is necessary for smart contract testing? Is there any alternative way, so that we can perform smart contract testing without truffle?
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2answers
78 views

msg.sender in contract is empty

I have the following deployment script var contract = web3.eth.contract(response.abi); var bytecode = response.bytecode; var options = { from: ...