在後端使用 web3 簽署乙太坊合約交易？

如何通過私鑰直接將帳戶導入 web3 庫，以便它可以被 myContract.methods.myMethod().call() 和 myContract.methods.myMethod().send() 等函式呼叫？我沒有執行自己的節點，而是使用 Infura。

正如 Ismael 所提到的，在這種情況下應該做的是使用 web3-provider-engine。使用自定義私鑰和 Infura API URL（甚至是 TestRPC）執行的範常式式碼片段如下：

//Provider Engine sub-modules

const ProviderEngine = require('web3-provider-engine')
const CacheSubprovider = require('web3-provider-engine/subproviders/cache.js')
const FixtureSubprovider = require('web3-provider-engine/subproviders/fixture.js')
const FilterSubprovider = require('web3-provider-engine/subproviders/filters.js')
const VmSubprovider = require('web3-provider-engine/subproviders/vm.js')
const NonceSubprovider = require('web3-provider-engine/subproviders/nonce-tracker.js')
const RpcSubprovider = require('web3-provider-engine/subproviders/rpc.js')

//EthereumJS Wallet Sub-Provider

const WalletSubprovider = require('ethereumjs-wallet/provider-engine')
const walletFactory = require('ethereumjs-wallet')

//Web3 Module

const Web3 = require('web3')

//Wallet Initialization

var privateKey = "3a1076bf45ab87712ad64ccb3b10217737f7faacbf2872e88fdd9a537d8fe266"
var privateKeyBuffer = new Buffer(privateKey, "hex")
var myWallet = walletFactory.fromPrivateKey(privateKeyBuffer)

//Engine initialization & sub-provider attachment

var engine = new ProviderEngine();

engine.addProvider(new FixtureSubprovider({
 web3_clientVersion: 'ProviderEngine/v0.0.0/javascript',
 net_listening: true,
 eth_hashrate: '0x00',
 eth_mining: false,
 eth_syncing: true,
}))

// cache layer
engine.addProvider(new CacheSubprovider())

// filters
engine.addProvider(new FilterSubprovider())

// pending nonce
engine.addProvider(new NonceSubprovider())

// vm
engine.addProvider(new VmSubprovider())

// Here the URL can be your localhost for TestRPC or the Infura URL
engine.addProvider(new RpcSubprovider({
 rpcUrl: 'https://mainnet.infura.io/YOUR_ACCESS_TOKEN',
}))

// Wallet Attachment
engine.addProvider(new WalletSubprovider(myWallet))

// network connectivity error
engine.on('error', function(err){
 // report connectivity errors
 console.error(err.stack)
})

// start polling for blocks
engine.start()

//Actual Initialization of the web3 module

var web3 = new Web3(engine)

引用自：https://ethereum.stackexchange.com/questions/29436