All Questions
32,382
questions
0
votes
0answers
2 views
TransactionException: Cannot unmarshal invalid hex string when deploying contract in web3j
I have a java server that uses web3j library with geth as the provider. When I tried to deploy my contract on my private test net. I got this error:
org.web3j.protocol.exceptions.TransactionException: ...
0
votes
0answers
3 views
Issue with go-ethereum on freebsd
I got an issue when I am trying to run a sample test code via go to access my full node.
Consider the following code snippet:
package main
import (
"context"
"fmt"
"log"
...
1
vote
0answers
13 views
Chainlink - on-chain contract functioning
The on-chain aggregation smart contract for ETH/USD on the mainnet (https://data.chain.link/eth-usd) is at this address https://etherscan.io/address/0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419#code.
If ...
1
vote
0answers
9 views
Cannot verify Contract - bytecode has small difference
I forgot to verify the ERC20 token contract after deploying it. Now after 5 months, Im doing it again and completely forget which compiler and if I accidently change anything on the code.
After ...
0
votes
1answer
11 views
ERC721 testing transferFrom()
How can I test (truffle test or development console) the following:
await nft.transferFrom(accounts[0], accounts[1], 1);
await nft.transferFrom(accounts[1], accounts[0],1);
The second line throws
...
1
vote
1answer
14 views
How many new nodes join the Ethereum Network per month? How many leave?
I'm researching the cost of serving old blocks to new nodes that need to synchronize and download the whole blockchain. I can indirectly estimate the bandwidth consumed to serve old blocks, if I know ...
0
votes
0answers
16 views
Transfer Failing in Solidity Smart Contract
I am calling the following function from a front-end on a Solidity smart contract, but it is not transferring the price and commission amounts properly with the call functions, although the ownership ...
0
votes
0answers
8 views
Connecting a geth node over LAN to a public geth node on my network
I need to run 2 geth nodes on separate computers on my network (ethereum Mainnet). I understand that I could connect them both to public peers the regular way over the internet simply by changing the ...
0
votes
0answers
8 views
I got an error installing Node GYP
I'm just about to work on a very big project, but I need this tool and it won't install
npm ERR! code EACCES
npm ERR! syscall rename
npm ERR! path /usr/local/lib/node_modules/npm
npm ERR! dest /usr/...
1
vote
0answers
8 views
Retrieve deposited number of Uniswap LP tokens from smart contract
I’m doing yield farming on a smart contract and I try to find out the total amount of my deposits. I know that I can follow the ERC20 tx on etherscan, but I would like to find an easier way. Under ...
0
votes
0answers
10 views
I can't call my functions in the components which I can improve to make web3 work correctly?
I'm having a problem with components, I'm using truffle unbox / react, I created a BuyForm.js component that will be the purchase form but I have problems trying to make the purchase I'm not able to ...
0
votes
1answer
9 views
Dual mining ETH/ZIL with 4GB?
I recently saw this video about dual mining of ETH and ZIL. The video especially targets GPUs with 3-4GB of VRAM. I still have to try it, but I'm wondering: isn't ETH dagger size bigger than 4GB? How ...
0
votes
0answers
10 views
Unblockable P2P Network possible?
P2P peer discovery has few methods which are multicast DNS on the local network, trackers, distributed hash tables, and etc.
But all these methods require first connection to a constant peer that ...
0
votes
0answers
8 views
Received DeclarationError when calling other contracts file name and its function
So I created 2 contracts where the first one will be the app logic contract and the other one is the database contract. So I tried to "truffle compile" my contract but receive ...
-2
votes
0answers
19 views
0
votes
0answers
9 views
Generate Ethereum account in a JSON/UTC v3
What are some trustful ways to generate an Ethereum account in a JSON/UTC v3 format? I know some web wallets, but I would prefer a very used/well-known desktop or plugin wallet.
Metamask does not ...
1
vote
0answers
11 views
Running ERC20 contract on RSK
I have been reading about RSK lately and was wondering about the compatibility and possibilities, so I wanted to ask for some basic info in case there's someone more knowleadgable.
I have a smart ...
0
votes
0answers
8 views
Where is OR using contract deployed?
Just trying to understand a bit about Optimistic Rollups. Was wondering where does the actual contract that uses ORs gets deployed? Is there a copy on both L1 and L2? I would assume yes, since how ...
0
votes
1answer
14 views
Etherscan Input bool is 1 or true or True
I want to execute a smart contract function that takes input bool.
Here for example makes the distinction that web3 uses javascript which doesn't consider 1 as true, but solidity does consider 1 as ...
1
vote
1answer
27 views
Get total supply of any ERC20 token in Solidity
I'm a new developper on Solidity and maybe this is a trivial question but it is a crucial point for my project.
Is there any way to get the total supply of any ERC20 token (WBTC, and others) on ...
0
votes
0answers
20 views
How do I pick up Ether after Crowdsale? And other questions
Testnet: Rinkeby
Address token: 0xeAD7ACF95b260E4C866a036F9E792759Ba0Ad4ce
Address Crowdsale:0xf2D4B282CE60A0abBE7fb74C694A9A04087E5519
Ethers credited at the end of Crowdsale: ...
0
votes
0answers
5 views
Geth/Parity node - When is a new block imported
Based on my observations and also on block-timestamps-vs-received-timestamp, I suppose that a block "n" is imported into geth or parity node, only after a block "n+1" is mined.
Is ...
0
votes
0answers
15 views
Challenge: What is Ethereum's 1 Billionth transaction?
I am trying to find ethereum's 1 billionth tx for a project but I don't know how I would go about finding this? Also if you already know what the tx is would be great if you could share! Thanks
0
votes
1answer
12 views
How to use Oraclize (Provable Things) in smart contractin Remix ide ? i have a program of exchanging Ethereum to USD [closed]
`pragma solidity > 0.7.0;
import "github.com/oraclize/ethereum-api/provableAPI.sol";
contract USDPrice is usingProvable {
uint public price;
event Log(string text);
function USDPrice(...
0
votes
0answers
12 views
“No Contracts Deployed” TRUFFLE ERROR PLEASE HELP!
I really need help!
[12:20 PM]
i deployed an erc721 smart contract to testnet, it worked fine! Then i deployed it into the live network. It worked. But, i have an other script to mint my tokens. I ...
0
votes
0answers
17 views
How do I execute this Timelock contract on Remix Ethereum?
i am using a timelock smart contract but im not sure how to input the proper value to use this function on remix. what exactly do i put in data byte field? how do i get that data from the other ...
1
vote
1answer
18 views
What are the available options (March 2021) for bridging tokens across the chains?
Actual problem in mind
I would like to release a token for the Island DAO.
I'm worried that ETH gas prices are prohibitively expensive - if I use ETH, the smaller guys will not come.
But ETH is the ...
0
votes
0answers
13 views
Division and floor rounding with 18 decimals
I am recreating a UNISWAP-like AMM and have encountered problems anytime I want to divide the balances of tokens in my pool. For example: I want to require() that tokens are deposited in the correct ...
0
votes
0answers
9 views
How to add Lock Function on solidity?
I have code for the ERC20 token which has freeze, unfreeze, lockUser & unlockUser functions. I want:
When I lock someone he will be automatically unlocked after x days or,
Scheduled release of ...
0
votes
0answers
14 views
Truffle Mainnet - “No contracts deployed.”
I really need help! I created an ERC721 smart contract and deployed into the rinkeby test network. All was nice, after that I deployed into mainnet.
I set the gas price to 65 Gwei. Now the contract is ...
0
votes
0answers
13 views
Why must gas limit be set to 900 more than actual gas usage?
I have a contract which a specific function call will always cost x gas.
However, setting the gas limit of the transaction to anything less than x + 900 will result in an out of gas error.
What is ...
2
votes
1answer
11 views
Cancelled Transaction in MetaMask USDC leads to loss of funds
I had attempted to transfer 992 USDC from MetaMask to a Ledger Account but had decided to cancel the transaction. On cancelling, MetaMask reports that the cancellation succeeded, but my MetaMask USDC ...
0
votes
0answers
7 views
Is there any way to browse DeFi apps with “watch-only address” wallet?
I like to sign my transactions with a offline computer, then broadcast on the network with an online computer. This way I never get hacked.
With MEW, it is possible to send ETH to another address like ...
0
votes
1answer
14 views
The called function should be payable if you send value and the value you send should be less than your current balance. WITH NON-Payable functions
I have the following functions
function balance() public view returns(uint152) {
return uint152(IERC20(token).balanceOf(address(this)));
}
function balance1() public view returns(...
0
votes
0answers
19 views
Cannot find module '@truffle/db'
I am following a tutorial to build smart contract. And when I do the truffle migrate, there is en error shows can not find module truffle/db
0
votes
1answer
20 views
Does revert() send received ether back to sender?
When revert() undoes all state changes, does that include sending any received ether back to the sender?
For example, would both sendBackOne() and sendBackTwo() send ether back to the sender?
function ...
0
votes
0answers
14 views
GSN Contract but only for one function
I'm blindly trying to implement OpenGSN in my contracts. I'm still not sure how it works. Do I need a special application running and scanning for signed messages on my computer to make it working?
I ...
0
votes
0answers
10 views
Is it possible to install 2 geth ethereum nodes with one external ip?
I want to install 2 nodes in one local network, will I succeed? and what is needed for this?
1
vote
1answer
15 views
How to extract the URL of a crypto art as it appears within the NFT? and technical details like ERC-token type?
The following piece of crypto art has a title, description, and additional details regarding file and image size, provided by the NFT platform (Makersplace) where the artist (Lumi) minted the NFT for ...
0
votes
1answer
23 views
If crypto art is stored off-chain, how does the collector have any control over their NFT's contents if the server where it is saved shuts down?
CryptoKitties essentially sells crypto art NFTs to collectors on the Ethereum blockchain. However, the pictures of the cryptokitties are stored on the company's server, since the NFT merely represents ...
1
vote
1answer
19 views
How to recognize if a website is a DApp?
A Launch App button often appears on the top-right corner of Ethereum-platform websites. Is this an indication that a link is a link to a DApp (decentralized application)? Are the following two ...
0
votes
0answers
14 views
From what source does etherscan.io aggregate and broadcast data that appears on the blockchain ledger?
as blocks are hashed together as transactions pile up and are broadcasted on the Ethereum blockchain, how exactly does the website etherscan.io in turn publish and broadcast all that information in ...
0
votes
1answer
12 views
Can't use Uniswap contract function 'swapExactTokensForETH'
When using Uniswap function swapExactTokensForETH() I get the following error:
'TransferHelper: ETH_TRANSFER_FAILED'
Contract code:
pragma solidity 0.8.0;
import "https://github.com/Uniswap/...
0
votes
0answers
6 views
web3.py - AttributeError: 'Eth' object has no attribute 'get_block'
So... I'm probably being super dumb - but I started using web3.py in a jupyter notebook and it connects to the node just fine... but I can't seem to use any .eth methods as it throws a: AttributeError:...
0
votes
1answer
19 views
How to validate a transaction from any block in Blockchain
Given that we have a Blockchain with smart contracts. We have end users operating the platform for some time. Now one user wants to verify the claim of a transaction.
Example, I have to prove that ...
0
votes
0answers
8 views
im looking for an exchange to trade my tokens cheap
0
Is there any other site i can send my tokens to, where i can trade them for like a normal rate like on binance? trying to trade 50$ worth of token but the gas fees are 80$ - to 140$ how does that ...
0
votes
0answers
9 views
Is ownership of tokenized real assets through NFT upheld by law?
Let's say you've tokenized your house as a non-fungible token (NFT) on the Ethereum blockchain.
if an NFT simply represents ownership of a tokenized asset, what actors or agencies currently will ...
2
votes
2answers
28 views
What tokenized assets can be stored on-chain?
Examples of digital assets that can be tokenized as NFTs are:
crypto art (.jpg or .png file stored off-chain)
game weapons or characters
Examples of physical assets that can be tokenized as NFTs are:...
1
vote
0answers
13 views
My contract shows a zero balance on Metamask
I just need some help on a contract I'm doing an experimental project token for.
My setup as follows:
Using Remix for solidity
Metamask account linked Contract is using
pragma ^0.4.4 (original code ...
0
votes
0answers
5 views
Truffle not working after install using npm
I just tried to install truffle using npm. I followed the documentation and did
npm -g install truffle
However, after that, when I try to do anything (such as just run truffle or truffle --version), I ...