JavaScript区块链模拟：自动挖矿及性能分析

extends layout

block content
  .container-fluid
    h1 #{__('Blockchain')}
    .row.row-horizon
      - var blocks = []
      - for (var i = 1; i <= 1000; i++) {
        - blocks.push({block: i, chain: 1, nonce: i, previous: '0000000000000000000000000000000000000000000000000000000000000000'})
        - }
      each block in blocks
        .col-xs-7
          include includes/block

  script.
    $(function() {
      var miningTimes = []; // 用于存储每次挖矿的时间

      for (var i = 1; i <= 300; i++) {
        var startTime = performance.now();
        for (var j = 1; j <= 1000; j++) {
          setup(j, 1);
          mine(j, 1, false);
        }
        var endTime = performance.now();
        miningTimes.push(endTime - startTime);
        console.log('第 ' + i + ' 次挖矿耗时：' + (endTime - startTime) + ' 毫秒');
      }

      // 计算平均挖矿时间
      var totalMiningTime = 0;
      for (var i = 0; i < miningTimes.length; i++) {
        totalMiningTime += miningTimes[i];
      }
      var averageMiningTime = totalMiningTime / miningTimes.length;
      console.log('平均挖矿时间：' + averageMiningTime + ' 毫秒');
    });

    function getText(block, chain) {
      return $('#block'+block+'chain'+chain+'number').val() +
             $('#block'+block+'chain'+chain+'nonce').val() +
             $('#block'+block+'chain'+chain+'data').val() +
             $('#block'+block+'chain'+chain+'previous').val();
    }

    function setup(block, chain) {
      updateHash(block, chain);
      $('#block'+block+'chain'+chain+'mineButton').click(function(e) {
          e.preventDefault();
          var l = Ladda.create(this);
          l.start();
          setTimeout(function() {
              mine(block, chain, true);
              l.stop();
            }, 250); // give UI time to update
        });
    }


var difficulty = 5;        // number of zeros required at front of hash
var maximumNonce = 50000000; // limit the nonce to this so we don't mine too long

// NOTE: Because there are 16 possible characters in a hex value, each time you increment
// the difficulty by one you make the puzzle 16 times harder. In my testing, a difficulty
// of 6 requires a maximumNonce well over 500,000,000.

/////////////////////////
// global variable setup
/////////////////////////
var pattern = '';
for (var x = 0; x < difficulty; x++) {
  pattern += '0';
}

/////////////////////////
// functions
/////////////////////////


function sha256(block, chain) {
  // calculate a SHA256 hash of the contents of the block
  return CryptoJS.SHA256(getText(block, chain));
}

function updateState(block, chain) {
  // set the well background red or green for this block
  if ($('#block' + block + 'chain' + chain + 'hash').val().substr(0, difficulty) === pattern) {
    $('#block' + block + 'chain' + chain + 'well').removeClass('well-error').addClass('well-success');
  }
  else {
    $('#block' + block + 'chain' + chain + 'well').removeClass('well-success').addClass('well-error');
  }
}

function updateHash(block, chain) {
  // update the SHA256 hash value for this block
  $('#block' + block + 'chain' + chain + 'hash').val(sha256(block, chain));
  updateState(block, chain);
}

function updateChain(block, chain) {
  // update all blocks walking the chain from this block to the end
  for (var x = block; x <= 5; x++) {
    if (x > 1) {
      $('#block' + x + 'chain' + chain + 'previous').val($('#block' + (x - 1).toString() + 'chain' + chain + 'hash').val());
    }
    updateHash(x, chain);
  }
}

function mine(block, chain, isChain) {
  var t0 = performance.now();
  for (var x = 0; x <= maximumNonce; x++) {
    $('#block' + block + 'chain' + chain + 'nonce').val(x);
    $('#block' + block + 'chain' + chain + 'hash').val(sha256(block, chain));
    if ($('#block' + block + 'chain' + chain + 'hash').val().substr(0, difficulty) === pattern) {
      if (isChain) {
        updateChain(block, chain);
      }
      else {
        updateState(block, chain);
      }
      break;
    }
  }
  var t1 = performance.now();
}