区块链Demo：修改blockchain.pug和blockchain.js实现自定义数据生成和挖矿难度统计

修改区块链Demo：自定义数据生成和挖矿难度统计

本教程将指导你修改blockchain-demo项目中的blockchain.pug和blockchain.js文件，实现以下功能：

1. 顺序生成区块数据: 使区块链依次包含数字1到1000，共计1000个区块。2. 统计挖矿平均时间: 对每个区块进行300次挖矿，并统计不同挖矿难度下所需的平均时间。

修改 blockchain.pug

在blockchain.pug中，我们需要添加一个表单，以便用户输入数据：pugform(action='/mineBlock' method='post') input(type='number' name='data' placeholder='输入数据') input(type='submit' value='挖矿')

修改 blockchain.js

在blockchain.js中，我们需要进行以下修改：

1. **接收并处理输入数据:**javascriptapp.post('/mineBlock', function(req, res) { var newData = []; for (var i = 1; i <= 1000; i++) { newData.push(i); } var newBlock = generateNextBlock(newData); addBlock(newBlock); broadcast(responseLatestMsg());

console.log('已添加区块: ' + JSON.stringify(newBlock)); res.redirect('/blocks'); });

2. **修改generateNextBlock函数，使其生成包含顺序数据的区块:**javascriptvar generateNextBlock = function(data) { var previousBlock = getLatestBlock(); var nextIndex = previousBlock.index + 1; var nextTimestamp = new Date().getTime() / 1000; var nextHash = calculateHash(nextIndex, previousBlock.hash, nextTimestamp, data);

return new Block(nextIndex, previousBlock.hash, nextTimestamp, data, nextHash);};

3. **修改proofOfWork函数，进行300次挖矿并统计平均时间:**javascriptvar proofOfWork = function(index, previousHash, timestamp, data, difficulty) { var target = Array(difficulty + 1).join('0'); var nonce = 0; var startTime = new Date().getTime();

while (true) { var hash = calculateHash(index, previousHash, timestamp, data, difficulty, nonce); if (hash.substring(0, difficulty) === target) { var endTime = new Date().getTime(); var timeTaken = endTime - startTime; console.log('区块已挖矿: ' + hash + ' 耗时 ' + timeTaken + 'ms'); return { hash: hash, time: timeTaken }; } nonce++; }};

// 在主函数中执行300次挖矿并统计平均时间var main = function() { // ... var difficulties = [1, 2, 3, 4, 5]; // 设置不同难度 var avgTimes = {};

for (var i = 0; i < 300; i++) { for (var j = 0; j < difficulties.length; j++) { var difficulty = difficulties[j]; var result = proofOfWork(nextIndex, previousBlock.hash, nextTimestamp, newData, difficulty); if (avgTimes[difficulty]) { avgTimes[difficulty] += result.time; } else { avgTimes[difficulty] = result.time; } } }

for (var difficulty in avgTimes) { avgTimes[difficulty] /= 300; console.log('难度 ' + difficulty + ' 的平均挖矿时间: ' + avgTimes[difficulty] + 'ms'); }