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PORT ERROR!! Set up a Private Ethereum instance with Geth on MacOS

Hello I am trying to set up a private ethereum instance with geth on MacOS I have a startnode.sh file using ATOM But every time I try to start the node with "./startnode.sh", the http access account ...
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14 views

What does “starting offset” mean in the context of using abi.encode?

Starting with a simple example. If you just encode a single string like, abi.encode("AAAA"); You get the following output (96 bytes, 3 words) ...
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4 views

Download Etherscan input data via API

I am unable to find the correct API call format to download the input data field from the event log of each transaction - is there a way to use API key to download this information? I am referring ...
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6 views

Truffle develop freezing. Trying to check variable values

truffle-config.js module.exports = { compilers: { solc: { version: "^0.6.0" } }, networks: { development: { host: "127.0.0.1", port: ...
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5 views

get event logs and debug trace from eth_call

I am looking for a way to execute a transaction locally (using local geth/parity node) for simulation only, before actually submitting it to blockchain. I know that I can use 'eth_call' RPC call and ...
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7 views

Aragon: How to update files after a contract compiles

I need to update certain files (in app/public/) every time when a contract compiles. Namely I need to extract the ABI from a contract and store in app/public/. Is it possible with the current version ...
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1answer
11 views

remix compiler warning infinite gas requirement

I'm trying to deploy a trivial faucet program which compiles OK with remix but I get the following error. "Gas requirement of function Faucet.withdraw(uint256) high: infinite. " This means that while ...
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0answers
19 views

Timeout when try to connect over websocket in web3.py

I am trying to listen for events emitted by a simple Solidity contract. I am not able to connect using ws though I can commit transactions using http. Here's my code for event listening - import ...
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0answers
23 views

What are “if” and “this” in this function?

function() public { if(delegate.delegatecall(msg.data)) { this; What are the requirements for "if" to execute "this" and what does "this" refer to in this function?
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22 views

Can I get a deployable bytecode from a contract?

In my truffle build files there are two types of bytecode for each contract: bytecode deployedBytecode web3.eth.getCode returns only the 2nd one. Can I access the original bytecode from web3? It ...
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0answers
10 views

How to pass a selected radio button value in reactjs to ethereum blockchain

I am new to react and ethereum. I am working on voting dApp where I want to pass the selected candidate with a radio button in react to the blockchain. How do i go about it? here is my code. I have ...
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0answers
10 views

Unable to get the Ethereum accounts (eth_accounts) using the JSON RPC

I launched an Ethereum installation with the Amazon Blockchain Templates using the simplest installation, the docker-local with a private network (not connected to the public Ethereum network). ...
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12 views

window.ethereum: 0 if use MetaMask

I try to connect to MetaMask from my DApp. It used two work well about two month ago, but now window.ethereum object is 0 (not undefined). For some reason ethereum object is 0. I am aware about ...
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1answer
19 views

Why is privateKey padded before secp256k1 signing?

I am checking how the Ethereum handles signing but I can't figure out why the math.PaddedBigBytes is necessary: func Sign(digestHash []byte, prv *ecdsa.PrivateKey) (sig []byte, err error) { if ...
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0answers
19 views

Transaction working in remix but not errored from dapp

I have a master contract which deploys instances of other contracts. pragma solidity ^0.5.0; pragma experimental ABIEncoderV2; contract DataEntityContract { DataEntity DE; constructor(...
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13 views

Calling function of deployed contract and getting return value in matrix?

I am looking for some help here. I would like to know how (using matrix) that I could call a function of an already deployed contract on the Ropsten net and get the return value. I have searched a ...
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0answers
6 views

Mining software for FPGA BCU1525 [closed]

I have a new Xilinx FPGA BCU 1252 and I wanted to know what mining software i should be using. Any recommendations?
1
vote
1answer
26 views

Validating equality between two address variables

I'm testing the challengeOpponent function in my Connect4 contract in remix. The function creates a new Escrow contract instance so that each player in the game has a place to hold their funds until ...
0
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1answer
16 views

Should i move my erc20 token from ropsten to main network?

I have just created token in ROPSTEN network, so Im confused now... Can I use my tokens in main ether network (sel, give, etc) or I just van play with them in test network and forget...? Should i ...
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1answer
27 views

Searching for a value in a dynamic array

I understand that for loops on dynamic arrays are a big no no in Solidity, so I am trying to find an alternative to this problem. Goal: From a dynamic array of numbers, I am trying to extract the ...
2
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0answers
20 views

Blocks can't contain more than 81 transactions

I'm building a private blockchain with Parity clients. For performance testing, I'm submitting many identical transactions. One of the nodes has a GPU miner attached. There are 2 issues I cannot ...
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0answers
17 views

Ethereum, the decentralized application platform and smart contract enabled blockchain? [closed]

I am trying to understand ethereum blockchain development process. I am using windows os. I want to code that in visual studio code IDE . 1. If someone can help me explaining how code flows and tools ...
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0answers
12 views

Deployed contract address is getting undefined after few days on private network

I have a private blockchain where I am able to deploy my smart contracts successfully and then I am getting the address of my smart contract which I am storing on my relational db. In geth console ...
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0answers
13 views

Geth Providing error on its directory path

I have initilize my node1 with my genesis file which worked fine command is 'geth --datadir node1/ init genesis.json'. But with same geth when I try to run this command geth --datadir node1/ --...
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1answer
21 views

MITM attack in hosted wallets

i have a question: in the web wallets(hosted wallets)when user want to make a transaction and send the information to the wallet server , can a one change the information(man in the middle attack)?
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1answer
16 views

Bytecode: Does it Reveal What Language it Was Programmed In?

Does EVM bytecode have some indication to what high-level language it was programmed in?
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0answers
15 views

need large amount ropsten testnet ether [closed]

I'v develop dapp about private loan but I don't have enough ether for test this dapp and I don't have GPU to mine by myself (CPU mining is sucks) can any send me ropsten ether to this address ...
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1answer
15 views

What does MetaMask mean by stop injecting web3.js?

MetaMask announced that they will stop injecting web3.js here. I know previously MetaMask will add a global variable in browser window.web3 and this global lowercase web3 variable will be deprecated ...
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1answer
15 views

using .call(): contradictory recommendations

Solidity documentation: You should avoid using .call() whenever possible when executing another contract function as it bypasses type checking, function existence check, and argument packing. ...
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2answers
23 views

Setting a value for ERC20 token on private blockchain?

Background: Currently we have an Dapp running on Ropsten. We've created an ERC20 token on Ropsten. Our employees are awarded these tokens over time. We want to use Dappos to allow our employees to ...
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0answers
16 views

How unique are the event log ids?

I am using log_ids of events to keep track of which events I've processed. Log ids are formed using the word log followed by 8 hexadecimal characters i.e. log_d758eda8 The possible combinations of ...
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0answers
16 views

“Nonce too low” using contract.methods.myFunction().send()

Using web3 to build a contract from the ABI: contract = new web3.eth.Contract(JSON.parse(abi), '0x17c91A5a6f5e3E4BEaFC478D18C4A44D88833277', { from: '0x0Ad2b5CCe78D677fD000698a7E4Cde866DE189C6', gas: ...
0
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1answer
19 views

Lottery Winning number based on blockhash

After reading a lot of Info about this topic in this forum I am asking whether I can just use the formular winningNumber = uint256(blockhash(block.number-1)) % 100; e.g. 10 or 20 blocks after the ...
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2answers
22 views

Unable to deploy contract on Private Quorum Network

We just built a new 3 node quorum network but we are unable to deploy any contract on it. Please find the below info: Quorum vesrsion: Geth Version: 1.8.18-stable Git Commit: ...
0
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1answer
17 views

What is the use of a interface or function without implementation?

Take, for example, this code. The interface contains function without implementation, so how it's useful. pragma solidity ^0.5.0; interface Calculator { function getResult() external view returns(...
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0answers
16 views

How to get a list of struct that has a mapping as attribute

I have the struct Offer so that it contains already a mapping of assets. I have created a mapping of offers for the struct Offer storage. Now I need to implement the getAll function of Offer. The ...
0
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2answers
17 views

Web3.js eth.subscribe: on('changed', function(event){}) doesn't work with Metamask?

I write a demo DApp website with this javascript const web3 = new Web3(ethereum); const contractAddr = "0x0Aa27e4B13D5c08A8767B36a0ACb76ED4549B7EA"; const abi = ...; let inst = new ...
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0answers
10 views

An unsolved problem related to the Ethereum presale in 2014

I am writing on this forum because I am trying to solve this issue since years, with no success. I have an unsolved problem related to the Ethereum presale in 2014, due to a technical issue of the ...
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0answers
13 views

App freezes when using any Web3j sendAsync function

I'm developing an app using Web3j and Java Kotlin in Android Studio. However, I'm not sure why anytime I call a web3j function with sendAsync the app freezes. if(preferences.applicationPreferences....
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0answers
10 views

How much compression do Merkle Patricia Trees actually provide?

I like the idea of a MPT but extra information has to be stored to build them.. so I'm wondering how much they actually compress the data. Is there actually data/statistics somewhere for how much ...
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0answers
13 views

Calling decodelog with dynamic number of arguments

the number of input arguments is dynamic, how can I decode many log by one? this is all i tried to do for (let n = 0; n <= receipt.logs.length-1; n++) { if(event.code === receipt.logs[n]....
0
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1answer
19 views

how to do sales receipt

I have a marketplace. I wanted to make a sales receipt for each item sold. The sales receipt will indicate address_receipt,nameOfGood, amountOfGood,Price, sumPrice,address_transaction. What should I ...
0
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1answer
35 views

Getting “ReferenceError: unescape is not defined” when trying to call() a smart contract method from rasberry pi to a private geth network

> var contract1 = eth.contract(abi).at(address) undefined > contract1 { abi: [{.....] transactionHash: null, addRecord: function(), allEvents: function(), getPatientName: function(), ...
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0answers
8 views

Geographic distribution of keys in Key Management

I'm making key management for a company and there is a question about Geographic distribution of keys. I understand that the keys should be backed up in different locations, but about the geographic ...
0
votes
1answer
22 views

How can I extract a wallet address from event data?

I have a contract that returns event data including the sender's address: event Result( address indexed _walletAddress, string _name, uint256 _amount ) And in my Node.js app I try to ...
0
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0answers
27 views

bZx: exploit or attack? [closed]

Ethereum-based lending project bZx has been recently in the news due an expensive bug exploit, see here or here. In many articles this event is referred as an "attack". In fact every step performed ...
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0answers
17 views

Contract not getting deployed and no failed transaction is shown on rinkeby.etherscan.io

I deployed this same contract a week ago and it deployed successfully. Now when I try to deploy it I get a message in the console telling me 'Attempting to deploy contract from (my account)' but then ...
0
votes
1answer
18 views

Cross Origin Blocked? Setting up Infura provider

useEffect(() => { const loadWeb3 = async () => { const web3 = new Web3( new Web3.providers.HttpProvider("https://mainnet.infura.io/censored") ); let n = await web3....
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0answers
17 views

DIGIX tokens mapped with physcial gold ids?

If digix tokens are linked to Physical gold, what will happen to this linkage, if user transfers his tokens to other users.
1
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1answer
16 views

Information Regarding LASER and Ethereum

I was reading this article https://diligence.consensys.net/files/D1T2%20-%20Bernhard%20Mueller%20-%20Smashing%20Ethereum%20Smart%20Contracts%20for%20Fun%20and%20ACTUAL%20Profit.pdf and came across ...

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