All Questions

0
votes
1answer
12 views

How to automatically pre generate thousands of ETH addresses for my app users

I'm building an app where every user will have app-generated ETH Wallet to do transactions with internal ERC20 Tokens. I would like to pre-generate wallets for my users, and assign every wallet upon ...
0
votes
0answers
6 views

a contract in ropsten test network got lost

I deployed a contract in ropsten test network via remix days ago. Today, when I opened the remix, the contract disappeared, then I need to re-deploy once more. Anyone know why? Thanks.
1
vote
0answers
8 views

Predefine set of transactions to be added as soon as a private chain is initialised

I need some transactions with predefined data that needs to be added immediately after the genesis block. Apart from actually making those transactions through Geth, is there a way to automate these ...
1
vote
0answers
7 views

How do I enable web3 in Coinbase wallet?

I am building a very simple dapp. At first I want to initiate web3 on the webpage and then enable it so that I can access web3.eth.getAccounts(). MetaMask, and Opera Mobile both have a window....
0
votes
0answers
10 views

On an Ethereum private chain, can the rewards of mining be user-defined? [duplicate]

I have created my Ethereum private chain via Geth. I noticed that the rewards to block miners are pre-set as 5 Ether. Can I change this setting?
0
votes
0answers
9 views

VM Exception while processing transaction

I have some contract external calls when I execute a function and I get and error. The flow of the contract logic is so extensive. Its seems that is inside of the smart-contract logic. But I´m trying ...
0
votes
0answers
12 views

why .call() in Truffle did not return results as expected?

I'm deploying a contract to my private chain and try to call the contract's function. After I got in the geth console and finished deploy contract, I called the function but it doesn't work ...
0
votes
0answers
6 views

miner.start doesn't work in private network

i have created a private network with this genesis file { "coinbase" : "0x0000000000000000000000000000000000000001", "difficulty" : "0x400", "extraData" : "", "gasLimit" : "0x2fefd8", "...
0
votes
0answers
12 views

I am looking for testing framework which is capable of creating test scripts for smart contracts(solidity) automatically [duplicate]

Is there any testing tool which is capable of handling smart contracts and can generate test scripts for given contracts based on function present in that contract? End user only need to provide ...
2
votes
0answers
14 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 ...
0
votes
1answer
19 views

How to get all the function names with their respective parameters from smart contract?

I want to fetch the list of all functions with their parameters which are present in any smart contract.
1
vote
0answers
10 views

Hashnot matching generated from solidity contract and web3js

I want to make hash same as generating by solidity contract from web3 or ether's js. In solidity contract hash generation by below : sha256(abi.encodePacked(no of parameters)). Kindly help for it. ...
0
votes
1answer
11 views

TypeError: Invalid type for argument in function call. Invalid implicit conversion from int_const 0 to address requested

constructor(string memory enterOrganizationName) public { owner = msg.sender; status = true; addUser(0, "", ""); addUser(owner, 'Creator and Owner of Smart Contract', ""); ...
0
votes
0answers
6 views

Cannot connecting Remix to LocalHost!

I'm using windows 10 and i cannot connect VScode to Remix, i have both 'npm' and 'node.js' installed on my system. But i cannot connect to LocalHost. It works for me on ubuntu, but again only on Brave ...
0
votes
2answers
22 views

Atomic Transactions

Is there any way to ensure metaTransaction "atomicity". eg: contract first{ function one(uint256 a, uint256 b) public pure returns(uint){ uint256 c = a + b; return c; } ...
0
votes
1answer
13 views

Is it possible to modify privateFor addreses in a private Smart Contract (Quorum)?

I know how a private smart contract works providing a list of accepted addreses to privateFor property, but what if I want to disable (or enable) any address visibility? Should I deploy a new Smart ...
0
votes
0answers
2 views

Custom build Mist Wallet [on hold]

I want to custom build Mist wallet.I have downloaded the code.I am looking into code to make changes in the app but i am unable to understand the code. How can i customize it? any guideline please.
0
votes
0answers
10 views

How to call view function in geth/nodejs

This is my contract code: pragma solidity ^0.5.2; contract U { uint256 public index = 24; function getIndex() public view returns(uint256) { return index; } } This is my nodejs code: ...
0
votes
0answers
9 views

How to return a struct which contains another struct?

I'd like to return a struct which contains another struct. When calling the function, I want to make the return result likely to 0:string: Username 1:string[]: [[a.doc,...
0
votes
0answers
10 views

How to capture opcode executed for a transaction

In remix debug mode, we can see opcodes executed line by line for a transaction, is there any way we can print the list of opcode and their corresponding line number(maybe memory address?) when ...
1
vote
2answers
23 views

ERC721 Tokens - Hold ETH in the token?

Would it be possible to create a ERC721 Token for say a game item, but I want the Token to basically have ETH inside the token, so that a user could destroy the token to reclai
1
vote
0answers
20 views

How to intercept fork event using API?

I am wondering if there is a way to detect forks that may happen to an Ethereum chain. I looked in web3 library, but couldn't find anything. Any idea?
0
votes
0answers
41 views

How to connect my light node to my full node?

I hosted a full node on AWS that syncs the Rinkeby testnet. I have a Raspberry Pi as an IoT sensor running a light node. Unfortunately Rinkeby has the issue of very few full nodes that serve light ...
0
votes
1answer
9 views

Private Network on restart balance and transaction is gone?

I am running a private ethereum node with a single node. and it creates a folder for the keystore and chaindata But on restart, all the data is gone even the balance as well. init genesis.json is ...
0
votes
0answers
13 views

Quorum deploy with Web3j timeout

SCENARIO: I have the following code: final String hostUrl = this.deployerProperties.getProperty("quorum.host.url"); final String hostPort = this.deployerProperties.getProperty("quorum.host.port"); ...
0
votes
0answers
11 views

async handleSubmit(event) not working

This is the full code of App.js import SimpleStorageContract from "./contracts/SimpleStorage.json"; import getWeb3 from "./utils/getWeb3"; import "./App.css"; class App extends Component { state =...
0
votes
1answer
21 views

Smart contract method relayer

I was wondering if there was a way, in theory, to call from a sc two functions from a secondary sc in which the result from the first function is a parameter of the second function so something like: ...
0
votes
2answers
26 views

Deploying smart contract with undefined state variables

I have a factory contract (Factory.sol) that creates new contracts (YourContract.sol). The createNewContract function in the factory defines some state variables that the new contract picks up in its ...
0
votes
1answer
21 views

Regarding interaction between smart contracts [on hold]

If we have a case where we have Two smart contracts. Contract A passes value to Contract B. the address of contract A is also passed to contract B in the smart contract. while compiling the contract B ...
0
votes
0answers
8 views

Web3: Sending a signed serialized transaction throws an error: rlp: expected input list for types.txdata. Please help

I am feeding a signed serialized raw transaction to sendRawTransaction of web3. The problem is that whenever I call sendRawTransaction it throws an error: rlp: expected input list for types.txdata. ...
0
votes
1answer
14 views

How to remove byte code of deployed smart contract which was deployed using Ropsten Test Network?

I 've deployed my smart contract on Etherscan using Ropsten Test network. I can see there is bytecode for my deployed contract on ropsten etherscan. I want to hide or don't want to show the bytecode ...
0
votes
1answer
18 views

TypeError: tokenInstance.balanceOf is not a function

It happen when use truffle test, here my contract file: pragma solidity ^0.5.0; import "./DappToken.sol"; contract DappTokenSale { address payable admin; DappToken public tokenContract; ...
0
votes
0answers
8 views

if RecoverCompact succeeds, does it prove that signature is right?

eth not use VerifySignature to ensure signature,but use recovecompact func, does it means that signature is right if recoverPlain succeeds, // Validate the transaction sender and it's sig. Throw // ...
0
votes
1answer
18 views

How can I create an array of objects of a specific smart contract in solidity?

I am developing a university management system using ethereum. So,for that I need an entity "Student" and I have created a smart contract with some basic functionalities. Here is my code snippet for ...
0
votes
0answers
20 views

supply chain contract

As per this contract can some explain about the what input the user will provide and explain about the transporter type when he select option 1 then what input should we give. please explain about the ...
0
votes
0answers
21 views

Node: How Can I Import Web3 To Node.js?

I'm trying to import the web3 library in Node.js so that I can handle Ethereum smart contract events, however I can't get the import to work. I'm running Babel on each file to convert to es5, and the ...
3
votes
1answer
92 views

Can someone explain the meaning of derivation path in wallet in plain English (such as m/44'/60'/0'/0)?

Like m / purpose' / coin_type' / account' / change / address_index which gives say a value of m/44'/60'/0'/0 What is the meaning of "m", purpose, coin type, etc.
0
votes
0answers
11 views

How do i select a random number from a given range in my contract? [duplicate]

I am trying to create a simple gambling app in which the users are all assigned numbers when they enter the contest and i need to select a winner based on this number. Consider the numbers are 1-100 ...
0
votes
0answers
7 views

How to generate wallet using MyEtherWallet source codes?

I'm trying to do a simple task of just generating public address and private key on a simple site using MEW codes from https://github.com/kvhnuke/etherwallet I couldn't find like a function that I ...
0
votes
0answers
7 views

Send ETH on Command Line with Parity

How do you send ETH on the command line with Parity? I am trying this on a node running Parity 2.4.5: curl -H "Content-Type: application/json" -X POST --data '{"jsonrpc":"2.0","method":"...
0
votes
1answer
15 views

tokenInstance.balanceOf is not a function

It happen when use truffle test, and here my DappTokenSale file: var DappToken = artifacts.require('./DappToken.sol'); var DappTokenSale = artifacts.require('./DappTokenSale.sol'); contract('...
0
votes
1answer
13 views

ReferenceError: admin is not defined

It happen when use truffle test, here my contract file: pragma solidity ^0.5.0; import "./DappToken.sol"; contract DappTokenSale { address payable admin; DappToken public tokenContract; ...
0
votes
1answer
16 views

VM error: revert. revert The transaction has been reverted to the initial state

Here my contract pragma solidity >=0.4.21 <0.6.0; import "./CertificateOwnable.sol"; import "./CertificateStorage.sol"; contract Certificate is CertificateOwnable { CertificateStorage ...
0
votes
0answers
20 views

What is wrong in this contract? [on hold]

contract Vuln { mapping(address => uint256) public balances; function deposit() public payable { // Increment their balance with whatever they pay balances[msg.sender] += ...
0
votes
1answer
26 views

Web3js :interact with smart contract

I'm currently struggling to interact with my smart contract, I don't if it comes from the way I call the function or the way I connect to my smart contract. Here is the code const contractAddress = '...
0
votes
0answers
2 views

Implementing Whisper in Dapp without local node?

I was thinking of implementing chat functionality on top of whisper, however the few examples I've seen all have running a local node as the first step. Example - https://github.com/ethereum/meteor-...
0
votes
0answers
33 views

How does UTXO fit into this schema?

I have been rather confused by the eponymous web3 stack introduced by the Web3 Foundation. https://wiki.web3.foundation/en/latest/tech_stack/Layer-0/platform_neutral_computation_description_language/ ...
1
vote
0answers
13 views

Contract deployment error using rinkeby/infura. Error encountered, bailing. Network state unknown. Review successful transactions manually

I try to deploy smart contracts using Infura to the rinkeby test network and got this error: Running migration: 1_initial_migration.js Deploying Migrations... ... ...
0
votes
0answers
9 views

NEthereum, Number of indexes don't match the number of topics

I would like to get all Transfer events for a specific interval of blocks. When I call GetAllChanges with the following parameters, I get this error message: 'Number of indexes don't match the ...
0
votes
1answer
7 views

What are the list of nodes at the bottom of kovan.json?

The Genesis file for Kovan has a list of nodes at the bottom. What are these nodes for? Is this just a list of known Kovan nodes? "nodes": [ "enode://...

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