All Questions

i have that question , how i know what function runs the transaction ?, let me explain , if i do a transaction in remix.ethereum i can see the transaction in the bottom and in the details of this i ...

How can I send a uint parameter value to the contract in truffle? i have a function that has two uint parameter and I wrote test that function but I guess the uint parameters cannt be sent as a ...

Dear Anyone Who Can Help Me, This is my first time posting and asking for help, I'm in the midst of Deploying and Running the Transactions in Remix IDE (as per the picture). I'm stuck at the Gas ...

I want to build a truly upgradable contract. I want the child contract to only implement state and then forward all functional requests to a main implementation contract. So the scheme should look ...

I have used infura in my App.js to connect to the kovan network. Then I am creating an instance of the smart contract deployed on that network. Then I am calling a function on that smart contract ...

How can I send a uint parameter value to the contract in truffle? i have a function that has two uint parameter and I wrote test that function but I guess the uint parameters cannt be sent as a ...

I'm trying to send a transaction that writes somesthing on ethereum(kovan) but it seems my transaction is not mined and probably not even send to the network? All my view requests to ethereum work, so ...

I need to send USDT and other ERC-20 tokens via Geth on Ethereum. I'm using PHP and Web3.php library to work with Ethereum. So far, it worked well for everything. Now, I need to start sending tokens ...

I've lunched Geth for the first time and created some accounts on it. While creating accounts, I entered a password for each, and a key file is generated which contains encrypted private key belonging ...

(Working from the Lynda Ethereum course) Running the test code below I get the following error: truffle tests Warning: Both truffle-config.js and truffle.js were found. Using truffle-config.js. ...

I'm writing Django app and want to send out tokens using Web3 once Coinpayments sends me callback about successfull payment. The problem is that Coinpayments sends multiple callbacks at once and just ...

As I read, getTransactionCount() returns the number of transactions sent from an address. Which of below items should I consider? Not to use returned nonce? Use the returned nonce number as a ...

I wanted to enter the value any 1 of the "d Price" text box To donate any amount of value. But its taking from only one textbox thats the 2nd textbox and 1st textbox is returning empty value This is ...

Please bear with me here, I have been trying to figure it out myself but couldn't. I am trying to learn upgradeability with a Proxy pattern .https://blog.gnosis.pm/solidity-delegateproxy-contracts-...

I wrote a function that generate a key value. the function codes is here mapping(string => bool) processedHash; mapping(uint => bool) HashList; function generateHash(uint256 ...

It seems there are two documented mechanisms for obtaining the chainId to identify if web3 provider is on mainnet or one of the testnets. The first that I've seen is using web3.eth.getId(). However, ...

If I send token and use relay service usually how much higher than the transaction without relay? Is it too much or how many percent? How can I find big relay service to use? Better with easy api.

I have developed some smart contracts and deployed/interacted with them successfully using truffle framework. However, when copying the main smart contract's address and it's ABI into myetherwallet to ...

How to find the ethereum relay service that is easy to integrate for sending erc20 tokens, or even usdt? Easy to integrate?

This is my first contract (working from Lynda course). Even when I use the supplied code I still age this error for the following code with I try to compile: TypeError: Type address is not implicitly ...

I am using quoram distribution through Azure blockchain service.. we are emitting few events according to our logic and these events are being used to get specific data from the transaction.. though ...

The problem: I call a smart contract function on my local blockchain, then I confirm the transaction on metamask and finally the transaction is submitted but the transaction does not get mined. On ...

I have docker-composer setup: Php and Geth. I can ping from php docker container to geth cont. but I cant get response from it. If I hard code ip address of this geth container, I get response if I ...

can I add a modifier (for ex: onlyOwner) to a mapping? only I must see the value of mapping's key by myself(onlyowner). For example: mapping (address => bool) onlyOwner getAddress; Thank you.

I'm trying to develop a mobile Dapp with React Native but I have a few questions: 1) Is it possible to call a smart contract methods like we do in web with metamask? 2) Is there any wallet that ...

What will it take intergrate Etherum Wallets for all my customers. I run a business and would love my customers to be able to create their own Etherum Wallets to receive and send.

For multi sign transaction, who will pay for the gas? Any sample code? I am not quite sure about this.

What is relay in ethereum?For doing transactions, any difference? I am not sure the concept of relay, it looks like one account can pay gas for transaction on another account.

If I use account1 sign transaction but use account2 send signed transaction who will pay the gas? Account2? Any sample code?

Whether I can sign the tx by private key 1 but I use private key 2 to sendrawtransaction, any sample code for this? Thanks.

I have a function inside my smart contract that fetches the timestamp of the block it's in: function getTime() public returns (uint256 time){ return block.timestamp;; } According to how I ...

I'm using Truffle and I want to increase the blocktime to mimic that of the mainnet when i run my tests. As i understand it, Truffle has already instantiated a web3 instance that's ready to use so i ...

Why I can use ethers.js and web3.js together? Thanks. In same nodejs.

I am using the ethers.js library, and am trying to code a transaction. Here is a snippet where I connect a wallet to a provider, connect to a contract I want to call a function in, and try to call the ...

Given the following function: function checkLock() external view returns (bool) { require( address(this) == IERC721(_nftRegistryAddress).ownerOf(_tokenId), "[...

https://github.com/ethereum/wiki/wiki/Ethash I have compiled above code but I am not able to write the dag into a file. Could anyone please help me on this? I have combined all code mentioned in ...

I want to simulate sending multiple transactions at the same time to a smart contract and i'm wondering if, for example, sending 100 transactions from one address is the same as sending 1 transaction ...

I had created a token using eth based blockchain via remix.ethereum.org But I need to verify the source code ,but I am not having the backup copy of source code How can I see the source code of the ...

How can I make an erc20 token transfer in node, I know to transfer eth is like this for using ethers. Lib: let privateKey = "0x3141592653589793238462643383279502884197169399375105820974944592" let ...

Here's the contract events I want to pull from the ropsten network. Here's how I constructed the event request event_request = ("https://api.etherscan.io/api?module=logs&action=getLogs"+ ...

What is max number that can be generated from receive() and did transactions use gas(fee)??I mad this and i can't send 0.009eth to my contract.Can anyone explain me why? pragma solidity ^0.6.4; ...

I'm facing a little issue here, that's the mintTo function from contract for NFT. Which I require the sender to send a value with >= 0.1 Ether: pragma solidity ^0.5.0; import "./TradeableERC721Token....

pragma solidity >=0.4.12; contract HealthRecords{ struct Contact { string symptoms; string medications; string allergies; uint weight; uint height; } mapping (uint => ...

I need to write some unit tests for my modules that involve in event processing. So I need to create an AttributeDict to make a mock event. Are there libraries exposed to do this?

This is an external function which will be called when a transaction have enough number of confirmations. function external_call(address destination, uint value, uint dataLength, bytes data) ...

Right now, I am running my private blockchain on aws ec2(t2.medium) using geth. I am just curious that later on is it possible to upgrade that aws ec2(t2.medium) instance to aws ec2(t2.large) instance?...

so I already successfully make a smart contract and deployed it on my BC network. I can execute the function using the Ethereum wallet. My question is, how can I execute the functions on Python ...

I am creating a MultiSigWallet contract. I compiled and deployed the MultiSigFactory contract to kovan network. But when I transfer funds to the contract it gets reverted, as shown on Etherscan.

This is a function that returns an array of addresses that confirmed for a transactionId. mapping (uint => Transaction) public transactions; mapping (uint => mapping (address => bool)...

I want to set my custom gas and gas Price in sendTransaction method.Currently I set it but when i send the transaction gas fee is showing 0.21 ETH in metamask. How can I solve this? web3.eth....