All Questions

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 ...

I'm running a geth node on a digitalocean droplet with: geth --light --rpc --rpcaddr "0.0.0.0" --rpcapi personal,web3,net,eth --rpccorsdomain "*" --rpcport "8545" console I'm trying to import a ...

For example, a function's name and parameters are given as following: function batchTransfer(address[] _receivers, uint256 _value) public returns (bool); Then I want to get a python dictionary whose ...

It says automatically sets environment for amd ...but also in v14.7 says both amd and Nvidia card supported except radeon7 cards...I guess what I'm asking is why can't I use my r7 or r6 ? I'm new to ...

I want to create a new account over IPC so I have started private chain with the below command geth --networkid=5 --datadir DataDir --ipcapi "db,eth,net,web3,personal" --ipcpath "/Users/smartSense/....

What be the advantages vs. disadvantages or running a general contract or spawning a new one for each instance. Let say, that I am providing a contract so people can create their own crowdfunding. ...

I have read some references to create ethereum transactions by a BACK-END server, all in low level, for example, requiring that I control the nonce by myself. Are there safe ways to avoid this control ...

My environment: geth 1.8.11 Ethereum Wallet Mist Browser windows 10 I try to deploy a new contract in the Ethereum Wallet. I execute (miner.start();) in the Geth JavaScript console to get some ...

What could be causing this ?

Envisage the following scenario: You are running a business, which requires a float to operate. Your float is x amount of USD This float yields a annual revenue of a XXX amount of USD This float ...

I mean not to exclude from already existin multi sig wallets, but create a wallet with such possibility. For example: The team of 4 people want to accept temporary 5th member (give him the right ...

[SOLVED]: See below. I am taking a blockchain and security class and we are working with vyper. We have been tasked with rewriting a fundraising smart contract. However, the compilers do not seem to ...

I am hosting my own ethereum node using geth and I have some simple dApps which make use of the web3.js library. I went through various documentations related to the hard fork, more specifically this ...

According to the MetaMask docs the recommended way to access the web3 is by creating a new instance of the Web3 class by passing the window.web3.currentProvider, which is injected by the MetaMask ...

pragma solidity ^0.4.24; contract owned { address public owner; function owned() public { owner = msg.sender; } modifier onlyOwner { require(msg.sender == owner); ...

Here is the the scenario. Users come to my website and register(by using email and password). Then they login. After that, They add a new item(which has name and quantity fields). After Clicking ...

In other words, say In Python I have something like that: signed_txn = w3.eth.account.signTransaction(dict( nonce=w3.eth.getTransactionCount('0x0000000000000000000000000000000'), gasPrice = ...

I am working windows 10 and have both truffle.js & truffle-config.js I am using command truffle migrate --reset --networks rinkeby Error produced: Unknown network "ganache". See ...

Is there a CLI command where I can pass in an ethereum private key and send some coins to another address? I'm trying to build out a reoccurring payment system where a user can send 1 eth to another ...

I'm trying to perform a function that exchanges one token for another, but I'm getting a very strange bug. If I call the function in web3, I get the standard metamask popup asking whether to confirm ...

Say I have a function that handles 4 cases via if statements. I could break that into 4 separate functions. The case for breaking it up is that each function call would use less gas. The case against ...

I did this command on parity parity --chain mainnet account new I got the address but, How can I export or see the private key?

I want to retrieve and assign the value of my contract state variable to my javascript variable.I am doing as per guidlines provided on this community, but failed to assigned. my javascript code is ...

I'm looking at events on the exchange contract address: https://etherscan.io/address/0x61935cbdd02287b511119ddb11aeb42f1593b7ef#events with a topic_0 equal to ...

I'm not familiar with webpack, but after reading this error all I know that I import one module that is undefined by webpack. However, I don't know why export default new web3.eth.Contract(abi, ...

Im Trying to create a DAPP with two contracts generating assets. One is acting as the "factory" for the other contracts. From the latter I try to call a function in the factory without knowing its ...

This is the classic reentry attack: function withdrawBalance() public { uint amountToWithdraw = userBalances[msg.sender]; (bool success, ) = msg.sender.call.value(amountToWithdraw)(""); ...

There is a code, the essence is this: I need to check the account balance for erc20 tokens, and if the balance is not zero, I need to send eth from another account to this one, after eth reaches the ...

This question have just been published in StackOverflow as well, but you might be able to guide me on a better direction: I'm looking for the most valid path to download and keep downloading every ...

I am developing a Web3 app for a private Ethereum network. Throughout the development I used ganache-cli and now I wanted to test in the private live network. I can successfully interact with the ...

I plan to use web3 server side using NodeJs with geth. For production usage, should I do a full sync or fast sync is enough? Also, how much space do I need to store the blockchain data for each of ...

In order to modify GetBalance function to fork go-ethereum, I find difficulties to get a reference of the running evm. The function has a reference for self *StateDB: func (self *StateDB) GetBalance(...

I have multiple Pi's connected to a miner in a private network, where one pi is collecting sensor data, and am able to send ether from all the devices and they are all synchronised with the private ...

I create my transactions with ethers.js and push them into an array like this: const promises = []; promises.push(createTokenApprovalTx()); promises.push(createFooTx()); It's important that the ...

I have almost 800 .solc files of version ^0.5.12 (i am using also 0.5.13 compiler version), when i all give them to my input, to compile with following code; var walk = function (dir) { var ...

I am getting the warning on the code shown below. Could you please assist me know to resolve this warning ? warning message - "Is constant but potentially should not be"

I am unable to open a wallet I created roughly 2 years ago. In that time I have been using MEW, MetaMask and something that I installed locally on Window, which I forgot the name of. Not sure which ...

My question is if I'm not implementing ERC-20 methods in my contract, but I'm using already deployed ERC-20 contract methods in my contract, so can we say this will be ERC-20 compliant contract? ...

I am trying to experiment with ZoKrates library. When I use ./zokrates setup command, it warns me about gm16 malleability. So, I tried to change the proving scheme to gm17. But I keep getting the ...

I am trying to create a private chain. this are my details { "nonce": "0x0000000000000042", "mixhash": "0x0000000000000000000000000000000000000000000000000000000000000000", "difficulty": "...

I need to send eth to accounts that have erc20 tokens: foreth.forEach(function(item,i){ const balance = contractInstance.methods.balanceOf(item).call(function(err, result) { console.log(...

I have an event defined like this: event Created( address indexed target, string indexed name ); I do emit Created(..., _name); // called function with _name = "comment" which gives ...

I have created a mySQL database through phpMyAdmin, storing health data. I would like to use Solidity to develop a smart contract which will implement access control to the data in the database. My ...

To automate the signing capabilities I'm happy how clef is working. I've a couple of concerns though. answering the commandline prompts on clef init, clef clef attest, and clef. I'm wondering how i ...

I intend to trade tokens and coins using MyEtherWallet. Is it possible to use MEW to do Tx's between ALL coins and tokens, or is the wallet limit to a specific list?

I am new in solidity and i want to know about arbitration and dispute functionality in smart contracts any help will be appreciated

I am getting following error in parity ui. how to fix it.

I am trying to transfer ERC20 tokens on private ethereum network(POA) Transaction flow: raw tx object creation on backend. { "gasLimit": 37000, "gasPrice": 4000000000, "...

I have deployed a priavate etheruem Poa bloackchain to google cloud using puppeth everything is working fine but i can't figure out how to connect throw rpc to the private network ! please help ! any ...

Most tokens simply utilize the ERC20 functions transferfrom/transferto which just use some balances to add from one user to another - but what are the ones who allow you to: buy token cashout to ...