[Solidity][Metamask] Metamask 不再注入 web3

Question

我想更新与元掩码和solidity 交互的旧javascript 文件。 在服务器上它说 metamask 不再注入 web3？ 如何更改服务器的以下代码以请求元掩码帐户？

    try {
      const web3 = await getWeb3();
      const instance = new web3.eth.Contract(
        contractABI,
        contractAddress,
      );
      var userAccount;

      const accounts = await web3.eth.getAccounts();
      if (accounts[0] !== userAccount) {
          userAccount = accounts[0];
      }
      
    } catch (error) {
      // Catch any errors for any of the above operations.
      alert(
        `Failed to load web3, accounts, or contract. Check console for details.`,
      );
      console.error(error);
    }

Answer 1

试试看：

const Web3 = require('web3');
const web3 = new Web3(window.ethereum);
const accounts = await web3.eth.getAccounts();
var userAccount = accounts[0];

Answer 2

   npm i @metamask/detect-provider

它是一个微型实用程序，用于检测 MetaMask 以太坊提供者，或在 window.ethereum 注入的任何提供者。

import detectEthereumProvider from "@metamask/detect-provider";
import Web3 from "web3";

// in react or next.js this code should be placed in useEffect
 const provider = await detectEthereumProvider();
      if (provider) {
        const web3 = new Web3(provider);
        // now you have the provider
        // after this you can place the logic



   try {
      const instance = new web3.eth.Contract(
        contractABI,
        contractAddress,
      );
      var userAccount;

      const accounts = await web3.eth.getAccounts();
      if (accounts[0] !== userAccount) {
          userAccount = accounts[0];
      }
      
    } catch (error) {
      // Catch any errors for any of the above operations.
      alert(
        `Failed to load web3, accounts, or contract. Check console for details.`,
      );
      console.error(error);
    }
  // handle the case provider is not available
  } else {
    
    console.error("Please install Metamask");
  }
};