智能合约遇到的三个大坑

WINDOWS中安装WEB3始终不成功。

第一个坑，npm install web3 提示需要VC环境，安装VC环境也有问题

网上各种找资料，都是介绍以下方法：

npm install windows-build-tools
没有用。

最终解决方案为

npm install web3@^0.20.0
第二个坑，truffle部署的地址并不是testrpc中的account[0].其地址应该是truffle migrate时部署的地址。
testrpc中的accounts[0]

truffle migrate中的地址.如果这个地址找错了，会让web3找不到合约。

第三个坑。web3调用truffle部署好的合约后需要定义defaultAccount，否则会报invalid address错误而不能转账。查账是没有问题的。

const Base = require('./base.js');
var Web3 = require("web3");
//创建web3对象

// 连接到以太坊节点
if (typeof web3 !== 'undefined') {
web3 = new Web3(web3.currentProvider);
} else {
// set the provider you want from Web3.providers
web3 = new Web3(new Web3.providers.HttpProvider("http://localhost:8545"));
}
var abi = [ { "constant": true, "inputs": [], "name": "name", "outputs": [ { "name": "", "type": "string" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [ { "name": "_spender", "type": "address" }, { "name": "_value", "type": "uint256" } ], "name": "approve", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "constant": true, "inputs": [], "name": "totalSupply", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [ { "name": "_from", "type": "address" }, { "name": "_to", "type": "address" }, { "name": "_value", "type": "uint256" } ], "name": "transferFrom", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "constant": true, "inputs": [], "name": "INITIAL_SUPPLY", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": true, "inputs": [], "name": "decimals", "outputs": [ { "name": "", "type": "uint8" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [ { "name": "_spender", "type": "address" }, { "name": "_subtractedValue", "type": "uint256" } ], "name": "decreaseApproval", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "constant": true, "inputs": [ { "name": "_owner", "type": "address" } ], "name": "balanceOf", "outputs": [ { "name": "balance", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": true, "inputs": [], "name": "symbol", "outputs": [ { "name": "", "type": "string" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "constant": false, "inputs": [ { "name": "_to", "type": "address" }, { "name": "_value", "type": "uint256" } ], "name": "transfer", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "constant": false, "inputs": [ { "name": "_spender", "type": "address" }, { "name": "_addedValue", "type": "uint256" } ], "name": "increaseApproval", "outputs": [ { "name": "", "type": "bool" } ], "payable": false, "stateMutability": "nonpayable", "type": "function" }, { "constant": true, "inputs": [ { "name": "_owner", "type": "address" }, { "name": "_spender", "type": "address" } ], "name": "allowance", "outputs": [ { "name": "", "type": "uint256" } ], "payable": false, "stateMutability": "view", "type": "function" }, { "inputs": [], "payable": false, "stateMutability": "nonpayable", "type": "constructor" }, { "anonymous": false, "inputs": [ { "indexed": true, "name": "owner", "type": "address" }, { "indexed": true, "name": "spender", "type": "address" }, { "indexed": false, "name": "value", "type": "uint256" } ], "name": "Approval", "type": "event" }, { "anonymous": false, "inputs": [ { "indexed": true, "name": "from", "type": "address" }, { "indexed": true, "name": "to", "type": "address" }, { "indexed": false, "name": "value", "type": "uint256" } ], "name": "Transfer", "type": "event" }];
var address ='0x3be29127330474399a7449b16a1ec01980e71690';
//通过abi以及合约部署的地址实例化一个coin
var coin = web3.eth.contract(abi).at(address);
//必须先定义defaultAccount，不然会报invalid address错
web3.eth.defaultAccount= web3.eth.accounts[0];
module.exports = class extends Base {
async indexAction() {

console.log(web3.eth.defaultAccount);
this.assign('title11', web3.eth.coinbase);
await this.assign('xianjin',coin.balanceOf.call(web3.eth.coinbase));
// console.log(coin.balanceOf(web3.eth.accounts[1]));
// coin.transferFrom(web3.eth.accounts[0],web3.eth.accounts[1], 800);
coin.transfer(web3.eth.accounts[1],200);
// console.log(web3.eth.accounts[1]);
return this.display();
}
};

上面是thinkjs的一个controller 调用web3进行查账，转账200个币到accounts[1]