web3

问题 I used web3@1.00 in node.js to interact with private blockchain. And I write the code according to the official documents of web3@1.00. var Web3 = require('web3'); var Tx = require('ethereumjs-tx'); var web3 = new Web3('http://localhost:8101'); //get the privatekey var decryptPK = web3.eth.accounts.decrypt({"address":"68c5cb5aa9f568ae2a6ec530e982f4f1144f2d10", "crypto":{"cipher":"aes-128-ctr", "ciphertext":"96b6a86bd5ff16a5669975974eabba844bc414bc52d9cc36843b4f41e89d46b9", "cipherparams":{"iv

问题 I am developing a document verification system with ReactJS and solidity - smart contract. I want to display the result of my smart contract's get().call() method on the frontend, with a popup or even with a simple text. The problem I am facing now is that when I am trying to display the response of the method, it throws to me that error: Objects are not valid as a React child. If you meant to render a collection of children, use an array instead Here is the code of my solidity contract:

问题 I'm currently using 0.2x.x version of Web3 Javascript API. I deployed my custom ERC20 token by creating smart contract in solidity (on REMIX IDE). I installed the MetaMask and had a test on https://wallet.ethereum.org/ to send some custom ERC token to another my account. It worked well. I want to add the 'send custom ERC20 Token' function in my javascript code using Web3. Here is my code below. var http = require('http'); var Web3 = require('web3'); var Tx = require('ethereumjs-tx'); var abi

问题 I'm currently using 0.2x.x version of Web3 Javascript API. I deployed my custom ERC20 token by creating smart contract in solidity (on REMIX IDE). I installed the MetaMask and had a test on https://wallet.ethereum.org/ to send some custom ERC token to another my account. It worked well. I want to add the 'send custom ERC20 Token' function in my javascript code using Web3. Here is my code below. var http = require('http'); var Web3 = require('web3'); var Tx = require('ethereumjs-tx'); var abi

问题 I am running a private Ethereum network. I do use https://aws.amazon.com/blockchain/templates/ The entire setup has been done. Things look setup properly on AWS. Now, I am trying to create the account and retrieve all those accounts. For that, I am using methods as below. Web3Service.js var Web3 = require('web3'); var web3 = new Web3(new Web3.providers.HttpProvider(process.env.NETWORK_URL)); exports.getAccounts = function () { return web3.eth.getAccounts(); }; exports.createAccount = function

问题 I try implement a simple bank account example (get balance, deposit, withdraw). pragma solidity 0.5.1; contract Bank { int bal; constructor() public { bal = 1; } //get balance function function getBalance () view public returns(int) { return bal; } //withdraw money function withdraw (int amt) public { bal = bal - amt; } //deposit money function deposit (int amt) public { bal = bal + amt; } } I can get the balance of a simple account but I cannot use the deposit/withdraw functions as web3.eth

问题 I'm creating my first Ethereum contract with truffle. I want the web application to be usable without MetaMask so I was wondering if it is a good idea to run my own private node and to connect from the frontend like this: this.web3 = new Web3(new Web3.providers.HttpProvider('http://my-public-ip:8545')); Are there any security risks with this approach ? 回答1: I'm answering my own question because it seems that a lot of people are doinig the same mistake that I did and lose their ether ! I did

问题 I started learning ethereum and web3js and noticed some functions on Web3js are asynchronous. What i want to achieve is get the account balance of a wallet and use the data for something else. My code below function getAccountBalance2(address){ var wei, balance //address = document.getElementById("addy").value return new Promise(function(resolve, reject){ web3.eth.getBalance(address, function(error, wei){ if(error){ console.log("Error with address"); }else{ var balance = web3.fromWei(wei,

问题 This is a follow up question to the previous thread How to return json data to a react state? My react component makes an axios.post to an express server. The server uses web3 to sign a transaction onto Ethereum . Ethereum returns the following json object. Of note is that it takes some time (seconds to minutes depending on the miners) for the json to be returned: { blockHash: '0xcd08039bac40e2865886e8f707ce9b901978c339d3abb81516787b0357f53fbd', blockNumber: 4611028, ...other data...