Question

我正在使用blob在ajax的javascript下载器中工作。我想知道是否可以在客户端网络从同一点断开后继续下载。

我做了一个按钮，当单击该按钮时，打开一个ajax并再次发送，但它重新开始下载。

var xhr = new XMLHttpRequest();

var x0 = 0, y0 = 0;

xhr.open('GET', 'download.rar');
xhr.responseType = 'blob';

xhr.onerror  = function(e){

  console.log(xhr.readyState);

  div = document.createElement('div');
  document.body.appendChild(div);
  div.onclick = function(){
    xhr.open('GET', 'download.rar');
    xhr.responseType = 'blob';
    xhr.send();
  }
  div.innerHTML = 'CLIQUE PARA CONTINUAR';

}

console.log(xhr);

function normalizeSize( size ){

  if( size > Math.pow( 1024, 3) ){
    return (parseInt(size)/Math.pow( 1024, 3)).toFixed(2)+' Gb';
  }else if( size > Math.pow( 1024, 2) ){
    return (parseInt(size)/Math.pow( 1024, 2)).toFixed(2)+' Mb';
  }else if( size > 1024 ){
    return (parseInt(size)/1024).toFixed(2)+' Kb';
  }else{
    return size.toFixed(2)+' bytes';
  }

}

xhr.onprogress = function(e){

  console.log(e);

  var d = new Date();
  var time = d.getTime();

  if( x0 != 0 && y0 != 0 ){

    let spd = 1000*(e.loaded - x0)/(parseInt(e.timeStamp - y0));

    let medida = '';

    if( spd > 1024*1024 ){
      spd2 = spd/(1024*1024);
      medida = 'mb/s';
}else if( spd > 1024 ){
  spd2 = spd/1024;
  medida = 'kb/s';
}else{
  spd2 = spd;
  medida = 'bytes/s';
    }

    spd2 = Math.round(spd2);

    document.getElementById('velocidade').innerHTML = 'Velocidade: '+spd2+medida;
    document.getElementById('tempo_falta').innerHTML = 'Falta: '+(e.total-e.loaded)/spd+' segundos';

  }

  document.getElementById('progress').value = (e.loaded/e.total)*100;
  document.getElementById('tempo_gasto').innerHTML = 'Tempo Gasto: '+Number.parseFloat(e.timeStamp/1000).toFixed(2)+' segundos';
  document.getElementById('valor_baixado').innerHTML = 'Baixado: '+normalizeSize(e.loaded);
  document.getElementById('valor_falta').innerHTML = 'Falta: '+normalizeSize(e.total - e.loaded);
  document.getElementById('valor_total').innerHTML = 'Tamanho do arquivo: '+normalizeSize(e.total);

  x0 = e.loaded;
  y0 = e.timeStamp;

}

xhr.onload = function(e){

  document.getElementById('msgs').innerHTML = 'decodificando...';

  let blob = xhr.response;

  let url = URL.createObjectURL(blob);


  let a = document.createElement('a');

  a.download = 'download.rar';
  a.href = url;
  a.style.display = 'none';
  document.body.appendChild(a);

  a.click();

  window.URL.revokeObjectURL(url);

  document.getElementById('msgs').innerHTML = 'baixando';
}

xhr.send();

我希望出现错误后，下载会继续并且不会重新启动。

网络错误后继续Blob下载

0 个答案: