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Questions tagged [ethereum]

Ethereum is a blockchain currency (like Bitcoin) with a public ledger. Questions should relate to programming. General questions about Ethereum should be asked on https://ethereum.stackexchange.com

is an open-source, public, blockchain-based distributed computing platform featuring smart contract (scripting) functionality. It provides a decentralized Turing-complete virtual machine, the Ethereum Virtual Machine (EVM), which can execute scripts using an international network of public nodes. Ethereum also provides a cryptocurrency token called , which can be transferred between accounts and used to compensate participant nodes for computations performed. Gas, an internal transaction pricing mechanism, is used to mitigate spam and allocate resources on the network.

was proposed in late 2013 by Vitalik Buterin, a cryptocurrency researcher and programmer.

The official website of is Ethereum.org

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Why web3.eth.getAccounts().then(console.log) return empty array?

I got empty array after I tried to web3.eth.getAccounts().then(console.log);and also got a warning which is./node_modules/web3-eth-accounts/src/scrypt.js Critical dependency: the request of a dependency is an expression. In this project I first…
Jessie
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trying to call balanceOf function in ethereum using web3.py library but getting error

import json from web3 import Web3 infura_url = "https://mainnet.infura.io/v3/5b314a9b373442fc8ed0c9cd184e838f" web3 = Web3(Web3.HTTPProvider(infura_url)) abi=json.loads('[{"constant":true,"inputs":..........] large array') address =…
AnkushRasgon
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Different ways of getting Ethereum txpool pending transactions at Infura node via Web3.py

I would like to see the real-time pending transactions in the Ethereum txpool via Web3.py. I do not run a local node but use Infura instead. According to the documentation of Web3.py, apparently one has three different options: Use TX Pool API Use…
yisenhower
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Ethereum/Solidity - Query Transactions

Does solidity have the ability to query transactions it puts on the blockchain, based on data in the transaction? By query I mean within solidity code running inside a smart contract (not web3.js running outside a smart contract) So yesterday my…
Alex Kerezy
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gas required exceeds allowance or always failing transaction on Geth private blockchain but works fine in others

I have created a private blockchain using geth. I also have a contract in which there is a function which call another function it third contract to set an address. I can call this function on Local blockchains like testRPC and Ganache blockchain,…
Farzad Salimi Jazi
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Is it possible to pay transaction fee from another account in ethereum?

i want to do a transaction in ethereum from account A but the transaction fee should be paid from account B. is it possible in ethereum?
rahul123
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Can we get transaction information recorded in the past block using Solidity in the Smart contract?

I am studying blockchain with Ethereum, and I want to use past transaction data in the Smart contract using Solidity. If I use Web3.js module in the program written in javascript, I can get these data easily. But I can't get these data in the Smart…
i20gyawa
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Best practice to save files in blockchain

What is the best practice to save files as part of a blockchain's data? I have tremendously large files to be saved. Can't we save these file on cloud storage (centralized solution like dropbox), and link them with blockchain data using a file…
Bassel Kh
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Clique POA Signed recently must wait for others

This is my first time on this i hope somebody can understand my grammar and question. I have created 2 nodes using puppeth and choosing Clique for my private Ethereum. Both nodes are sealer (verify on both nodes using clique.getSigners()) and both…
qarina teal
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Web3j how to get transaction status

I am using web3j to query the Ethereum blockchain. Now I want to check if a transaction was mined or just sent to the network. How can I achieve this?
D. Muff
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How to know if a specific value exists in the mapping table or not?

I have a mapping table whcich stores multiple hashes into that table. What I want to do is that I want the user to add another hash with setinstructors() function and then try to look whether the same hash already exists in the mapping table or not.…
Vishva Patel
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What is the use of ethereum's RLPx and how do they use it in ethereum ecosystem

I understand that RLPx is a protocol based on Kademlia DHT but one thing i'm not sure about is what's the need for this protocol or the problem that it is trying to solve ? Further it says it's objective is to allow multiple protocols over single…
Ankit Singh
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Private blockchains Vs Hashgraph, Ripple, BigChainDb

I have been investigating different blockchains for some use cases. In the end, I came to the conclusion that setting up a private blockchain is equivalent to having a distributed database with blockchain concepts like immutability, digital…
Minisha
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Truffle migrate Error (after run testrpc)

I can´t migrate the standart contracts that come with truffle compile. Here´s what i do: truffle init truffle compile open other terminal and run testrpc truffle migrate and the first three step is smooth operation,but when i run truffle migrate…
zengcaifei
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Error when Installing Ethereum: Package 'ethereum' has no installation candidate

I am installing Ethereum on Ubuntu 17.10 following the steps in this article: https://medium.com/@mvmurthy/full-stack-hello-world-voting-ethereum-dapp-tutorial-part-2-30b3d335aa1f But when executing the following command: sudo apt-get install…
Muhammad Altabba
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