All Questions

0
votes
0answers
5 views

Truffle connection to Ropsten testnet fails

I'm getting an error when trying to connect to ropsten from Terminal, using the following command: truffle console --network ropsten Here's the error: truffle(develop)> truffle console --network ...
0
votes
0answers
2 views

Any php script to sign transaction?

Can you recommend some php script to sign transaction.Thanks.I want to find some php script to sign transaction and without using web3.
1
vote
0answers
9 views

How does Transactions work in Ethereum Virtual Machine?

While reading the transactions sections of EVM documentation many questions raised in my head: If the target account is not set (the transaction does not have a recipient or the recipient is set ...
1
vote
1answer
6 views

finacial transaction validation

I'm new at ethereum, new at blockchain development at all, and am wondering how can I validate simple money transfer from one address to another? I'm querying the blockchain with etherscan and have ...
0
votes
1answer
9 views

estimateGas for function calls

Can someone suggest me how to use estimateGas for function calls like below: await (MyContract.methods.addDoc(id,sha256hash).send({from: coinbase[0],gas: 1000000})
0
votes
1answer
5 views

Was it secure to think no more new transaction will be add to a block if a newer block was found in the context of mainnet?

friends My application having the needs to detect newest transaction from a EOA, and I am going to use https://etherscan.io's API. To reduce transaction scanning, I decides to recording the last ...
1
vote
2answers
373 views

How much Ethereum is used daily in gas?

I can see from this site - https://etherscan.io/chart/gasused - the amount of gas used on the Ethereum network daily. What I cannot work out is how much ETH that corresponds to. Is there some other ...
1
vote
1answer
10 views

ER_TRUNCATED_WRONG_VALUE: Incorrect datetime value: '1545042106' for column 'test123' at row 1

web3.eth.getBlock(12345).then(res => { connection.query(`INSERT INTO blockdata(bnumber,btimestamp) VALUES ("${res.number}","${res.timestamp}");`) }); I got timestamp already. I wanna insert data ...
1
vote
1answer
13 views

word length in mnemonic phrase

What is the standard length of words in the mnemonic phrase for various ethereum wallets ? I need to know this in order to decide what should be the choices given to the user while creating a ethereum ...
2
votes
1answer
15 views

'Runs (Optimizer) ' and 'Optimization' while verifying source code on Etherscan

This is about the parameters that we need to provide at the time of source code verification on Etherscan. I have a bit idea about it but i am looking for some deep and clear explanation. So my ...
1
vote
1answer
12 views

getting error ParserError: Expected type name function

I am new in solidity and trying some small code however I am getting error which I could not find. I am trying below code pragma solidity >=0.4.0 <0.6.0; contract property { uint public ...
1
vote
1answer
26 views

Asset based transfer Solidity Contract

I am trying to create asset based transfer Smart contract by solidity language. i'm using ethereum. functions are Create assets (land_id, land_size, land_price) with a ownership of contract owner. ...
1
vote
0answers
9 views

Mainnet sync Broken

I am having a Mainnet on Azure VM which was syncing the network as expected, but mean while after adding Ropsten network syncing on the same VM simultaneously I'm facing problem with Mainnet sync ...
-2
votes
0answers
21 views

credential in deploy smart contrat

Iam using Android studio with webj3 API to use smart contract deployed in the local machine using Ganache and Truffle Security.removeProvider(BouncyCastleProvider.PROVIDER_NAME); Security....
2
votes
1answer
19 views

ERC721 Metadata Creation (Newbie Question)

Complete newbie here so thanks in advance for tolerating the ignorance that follows. Working on creating a little card game to learn solidity and have reached the part where I need to assign metadata ...
2
votes
1answer
22 views

Add more logic to a payable function

Is it possible to include in a payable function a message such as "Transaction rejected - Company not registered" which is displayed when a transaction is rejected? My code is as per below: ...
1
vote
1answer
19 views

i want to compare hash that i have passed in the argument of the function but keep getting this error

function compare(string memory input, uint _y) public returns (uint){ bytes32 hashedinput = keccak256(input); } Error: Invalid type for argument in function call. Invalid implicit conversion from ...
1
vote
0answers
13 views

IPFS gateway not getting my files , Keeps on loading without any errors

After making all the client side scripts inside a folder which are needed for my website (in dist folder) checked with ipfs swarm peers : shows many results then adding the files with ipfs add -r ...
1
vote
1answer
15 views

tm.ipc: no such file or directory (socket file to use for the private API / IPC)

I am following this tutorial to setup a Quorum cluster: https://medium.com/@shizekun/how-to-set-up-a-quorum-private-chain-with-raft-consensus-and-dynamic-membership-bf826f3927e5 But unfortunately I ...
1
vote
1answer
17 views

Transfer from multiple inputs

Is there a way to send ether from several input addresses in one transaction WITHOUT the use of smart contracts? I wish that different transactions could not be linked to each other. A similar ...
1
vote
3answers
48 views

Can I easily generate a public address which has no private key?

I might be wrong in some of the facts that I state here, so please correct me if necessary. My understanding: Private key - 256 bits Public key - 256 bits Public address - the last 160 bits of a ...
2
votes
1answer
20 views

solidity-coverage adds extra events which make unit-test fail

It seems that when using the latest solidity-coverage (0.5.11), truffle (5.0.0-next.25) ganache-cli (6.2.4-beta.1) and solc (0.5.0) additional events / logs are emitted during tests which make the ...
1
vote
1answer
18 views

DApps that require stake

Does anyone knows apps that use the concept of proof-of-stake of ERC20 tokens? For example, applications like STEEM, that uses and its STEEM POWER. "STEEM Power is what gives you influence on Steemit....
2
votes
0answers
9 views

The '*.ldb' files in `~/.ethereum/geth/chaindata`are not sequence one after one, is it normal?

I start ethereum with command: geth --syncmode fast --cache 256 and I find my files in ~/.ethereum/geth/chaindata are like: 000390.ldb 000392.ldb 000420.ldb 000484.ldb They are not one after one. ...
1
vote
1answer
58 views

Recently upgraded Solc and Web3. Transactions with zero addresses now reverting with “invalid address” message?

I recently upgraded Web3JS and Solc. Now every time I pass a zero address to a Solidity contact method the transaction reverts with an "invalid address" message. This message appears to be coming ...
2
votes
2answers
38 views

Why is the Eternal Storage approach still used if it hugely increases gas usage compared to storing data in structs?

I was wondering why is the eternal storage approach (first code snippet) still used? I know it's meant to make contracts upgradable but it seems too expensive to me. contract Storage { mapping(...
1
vote
1answer
13 views

Inability to Log into MetaMask

I had a MetaMask account with password. Had used password to connect to DDex exchange for Ethereum connectivity, transactions, and token balance checks. Recently, I deactivated MetaMask from one of ...
1
vote
1answer
19 views

Interacting with dapps using wrapper smart contract (and not personal accounts)

Metamask (or other browser plug-in) helps a lot the user to submit transactions using his personal account since it manages his private keys. When interacting with an dapp front-end, web3 will ...
1
vote
0answers
21 views

Is there any way to integrate ERC20 token as payment to ecommerce [on hold]

If want to integrate ERC20 token to integrate as paymen to a website. how can?
1
vote
1answer
22 views

Is ApproveAndCall also vulnerable to double withdrawal attack as is Approve?

As above, is ApproveAndCall also vulnerable to double withdrawal attack? https://www.reddit.com/r/ethereum/comments/6uckdx/reminder_about_problems_of_most_erc20_tokens/
2
votes
1answer
38 views

What's the difference between 'address' and 'address payable'?

I saw a Solidity smart contract where some variables were declared with the type address and some were declared with the type address payable. What are the differences between the two? Do they store ...
1
vote
1answer
13 views

Constantinople fork replay protection

I was wondering... Will Constantinople hard fork surely replace the current fork? Is there any chance that the Constantinople fork and the current one will co-exist? If so, any replay attack ...
2
votes
0answers
29 views

Parse two API into one JSON for oraclize

I'm working with oraclize and Solidity and I need to get a URL of the API to query, usually "json().XX". The expected format is a JSON object with 2 fields or string like so: { "portfolioValue": 100....
1
vote
1answer
27 views

Unable to return address array in solidity

I have the following code for a simple gambling game. The code works fine except for getPlayers function pragma solidity >=0.4.22 <0.6.0; contract Lottery { address payable public manager; ...
2
votes
0answers
22 views

How can ethereum token use as payment gateway on ecommerce website [on hold]

I have problem that if I created ethereum token and I want to use it in real project . especially in payment gateway . How can integrate ethereum token as payment in ecommerce website and how can ...
1
vote
0answers
13 views

Metamask and web3 wrong behaviour when extension is disabled

Basically I have a dapp that gets the web3 object from window.web3 (the injected from metamask). When i disable de extention from chrome (not removing, just disabling) the web3 invocations are ...
2
votes
1answer
20 views

How to install Oyente on Windows 10?

Can some body please guide me how to install Oyente on Windows 10? I have found Oyente for Linux but not for windows on github. Some body please guide me. Zulfi.
1
vote
1answer
20 views

SyntaxError: Source file requires different compiler version

I am trying to compile the following contract on Remix IDE (online): pragma solidity ^0.4.24; contract ProofofExistence{ event ProofCreated( uint256 indexed id, bytes32 documentHash);/...
1
vote
0answers
14 views

How to setup Dapp on Cpanel? [on hold]

I have followed the truffle petshop tutorial and it runs in my local machine, I have a shared hosting account and i would like to upload and test this Dapp on my server to start to modify it. The ...
1
vote
1answer
16 views

Truffle-contract installed, but receiving error in Chrome console: Uncaught Error: Cannot find module 'truffle-contract'

I am working on my first end to end ethereum project. A problem that I am stuck on is that I have installed 'truffle-contract', but when I run my server and open the project in the Chrome browser, the ...
3
votes
2answers
680 views

If the hackers of the DAO converted the funds to bitcoin, would it have been possible to return the funds to the investors?

My understanding of the DAO hack is that Ethereum was hard forked so that those who lost funds could have them retrieved. If the hacked funds were immediately converted to bitcoin, would this still ...
2
votes
0answers
38 views

Call a function with an address attached (Solidity React)

I'm trying to make a frontend of calling a function with an address attached: function getAvailableAllocation(address _addr) constant returns (uint ethAvailableAllocation) { return ...
1
vote
0answers
13 views

ethereum-bridge: always return a callback error

I am using Oraclize for generating random number for my smart contract. I write unit test for testing oraclize things so I use ethereum-bridge written by Oraclize. Here is my problem: First: my smart ...
2
votes
1answer
11 views

How to configure truffle network with IPC provider?

How can I define in truffle the ipc connection to the node? Currently I am using in truffle.js host/port fields, which are used to create a HttpProvider. module.exports = { networks: { dev: { ...
1
vote
0answers
13 views

ethereum wallet running a private net 0 peers 0 waiting for blocks

am using geth VRSION: 1.8.20-stable-24d727b6 and ethereum wallet Ethereum-Wallet-linux64-0-9-3 and i am using Ubuntu 18.04.1 LTS in the geth console i started the miner but either is not ...
2
votes
0answers
14 views

Gas estimation failed

whenever I want to run this code I get this error "Gas estimation errored with the following message (see below). The transaction execution will likely fail. Do you want to force sending? VM ...
1
vote
1answer
19 views

ERC20- Error encountered during contract execution [Reverted] Transfer Already Created Token

I have created contract on Ropston TestNet which will send any already created tokens. Unfortunately its giving me error Transaction Details Available at: https://ropsten.etherscan.io/tx/...
2
votes
1answer
18 views

ethereum wallet:Your computer's clock is not synced.

i am using geth VRSION: 1.8.20-stable-24d727b6 and ethereum wallet Ethereum-Wallet-linux64-0-9-3 and i am using Ubuntu 18.04.1 LTS and on wallet startup wallet is showing the error message here ...
1
vote
2answers
37 views

Payable function with additional value attached (web3, React)

I'm making a React frontend for an open-source blockchain protocol for tokenized hedge funds. So the question is how to provide the payable function that requires some other value attached (n this ...
2
votes
0answers
21 views

Unable to send large transactions on ethereum private chain

I have a small contract pragma solidity ^0.4.17; contract A10test{ mapping(uint=>string) public data; uint public revisionNo=0; function setdata(string _data) public { data[revisionNo] = ...

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