本页目录

签名

启用扩展、选择账户，并将 API 客户端连接到目标链。根据链的当前元数据构建交易 payload；本指南中省略的十六进制数据均为占位值。

了解如何在 Polkadot 上签署交易和消息。

签署交易 Payload

签署交易 payload（extrinsic payload）：


import { web3FromAddress } from '@polkadot/extension-dapp'
 
// Get injector for specific account
const injector = await web3FromAddress(accountAddress)
 
// Sign payload
const payload = {
  address: accountAddress,
  blockHash: '0x...',
  blockNumber: '0x...',
  era: '0x...',
  genesisHash: '0x...',
  method: '0x...',
  nonce: '0x...',
  specVersion: '0x...',
  tip: '0x...',
  transactionVersion: '0x...',
  signedExtensions: [], // Populate from current chain metadata; do not sign this placeholder
  version: 4,
}
 
const result = await provider.web3SignPayload(payload)
 
console.log({
  id: result.id,
  signature: result.signature, // Hex signature
})

签署原始消息


const payload = {
  address: accountAddress,
  data: '0x48656c6c6f', // Hex-encoded message
  type: 'bytes',
}
 
const result = await provider.web3SignRaw(payload)
 
console.log({
  id: result.id,
  signature: result.signature,
})

监听交易事件


await tx.signAndSend(
  account.address,
  { signer: injector.signer },
  ({ status, events }) => {
    if (status.isInBlock) {
      console.log('In block:', status.asInBlock.toHex())
    }
    if (status.isFinalized) {
      console.log('Finalized:', status.asFinalized.toHex())
 
      events.forEach(({ event }) => {
        if (api.events.system.ExtrinsicSuccess.is(event)) {
          console.log('Transaction succeeded')
        }
        if (api.events.system.ExtrinsicFailed.is(event)) {
          console.log('Transaction failed')
        }
      })
    }
  }
)

RPC 方法

发送 RPC 请求


const response = await provider.web3RpcSend({
  method: 'chain_getHeader',
  params: [],
})
 
console.log('Latest header:', response.result)

订阅 RPC 事件


const subscriptionId = await provider.web3RpcSubscribe(
  {
    method: 'chain_subscribeNewHeads',
    params: [],
  },
  (response) => {
    console.log('New block:', response.result)
  }
)
 
// Unsubscribe later
await provider.web3RpcUnSubscribe()

错误处理


try {
  const result = await provider.web3SignPayload(payload)
} catch (error) {
  if (error.message === 'Cancelled') {
    console.log('User cancelled signing')
  } else {
    console.error('Signing failed:', error)
  }
}

在 React 中使用


import { useState, useEffect } from 'react'
import { web3Enable, web3Accounts } from '@polkadot/extension-dapp'
 
function usePolkadotWallet() {
  const [accounts, setAccounts] = useState([])
  const [isConnected, setIsConnected] = useState(false)
 
  const connect = async () => {
    const extensions = await web3Enable('My dApp')
    if (extensions.length > 0) {
      const allAccounts = await web3Accounts()
      setAccounts(allAccounts)
      setIsConnected(true)
    }
  }
 
  return { accounts, isConnected, connect }
}