PHP大文件分割分片上传实现代码

服务端为什么不能直接传大文件？跟php.ini里面的几个配置有关

upload_max_filesize = 2M //PHP最大能接受的文件大小
post_max_size = 8M //PHP能收到的最大POST值'
memory_limit = 128M //内存上限
max_execution_time = 30 //最大执行时间

当然不能简单粗暴的把上面几个值调大，否则服务器内存资源吃光是迟早的问题。

解决思路

好在HTML5开放了新的FILE API，也可以直接操作二进制对象，我们可以直接在浏览器端实现文件切割，按照以前的做法就得用Flash的方案，实现起来会麻烦很多。

JS思路

1.监听上传按钮的onchange事件

2.获取文件的FILE对象

3.把文件的FILE对象进行切割，并且附加到FORMDATA对象中

4.把FORMDATA对象通过AJAX发送到服务器

5.重复3、4步骤，直到文件发送完。

PHP思路

1.建立上传文件夹

2.把文件从上传临时目录移动到上传文件夹

3.所有的文件块上传完成后，进行文件合成

4.删除文件夹

5.返回上传后的文件路径

DEMO代码

前端部分代码

<!doctype html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport"
     content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    #progress{
      width: 300px;
      height: 20px;
      background-color:#f7f7f7;
      box-shadow:inset 0 1px 2px rgba(0,0,0,0.1);
      border-radius:4px;
      background-image:linear-gradient(to bottom,#f5f5f5,#f9f9f9);
    }

    #finish{
      background-color: #149bdf;
      background-image:linear-gradient(45deg,rgba(255,255,255,0.15) 25%,transparent 25%,transparent 50%,rgba(255,255,255,0.15) 50%,rgba(255,255,255,0.15) 75%,transparent 75%,transparent);
      background-size:40px 40px;
      height: 100%;
    }
    form{
      margin-top: 50px;
    }
  </style>
</head>
<body>
<div id="progress">
  <div id="finish" style="width: 0%;" progress="0"></div>
</div>
<form action="./upload.php">
  <input type="file" name="file" id="file">
  <input type="button" value="停止" id="stop">
</form>
<script>
  var fileForm = document.getElementById("file");
  var stopBtn = document.getElementById('stop');
  var upload = new Upload();

  fileForm.onchange = function(){
    upload.addFileAndSend(this);
  }

  stopBtn.onclick = function(){
    this.value = "停止中";
    upload.stop();
    this.value = "已停止";
  }

  function Upload(){
    var xhr = new XMLHttpRequest();
    var form_data = new FormData();
    const LENGTH = 1024 * 1024;
    var start = 0;
    var end = start + LENGTH;
    var blob;
    var blob_num = 1;
    var is_stop = 0
    //对外方法，传入文件对象
    this.addFileAndSend = function(that){
      var file = that.files[0];
      blob = cutFile(file);
      sendFile(blob,file);
      blob_num += 1;
    }
    //停止文件上传
    this.stop = function(){
      xhr.abort();
      is_stop = 1;
    }
    //切割文件
    function cutFile(file){
      var file_blob = file.slice(start,end);
      start = end;
      end = start + LENGTH;
      return file_blob;
    };
    //发送文件
    function sendFile(blob,file){
      var total_blob_num = Math.ceil(file.size / LENGTH);
      form_data.append('file',blob);
      form_data.append('blob_num',blob_num);
      form_data.append('total_blob_num',total_blob_num);
      form_data.append('file_name',file.name);

      xhr.open('POST','./upload.php',false);
      xhr.onreadystatechange = function () {
        var progress;
        var progressObj = document.getElementById('finish');
        if(total_blob_num == 1){
          progress = '100%';
        }else{
          progress = Math.min(100,(blob_num/total_blob_num)* 100 ) +'%';
        }
        progressObj.style.width = progress;
        var t = setTimeout(function(){
          if(start < file.size && is_stop === 0){
            blob = cutFile(file);
            sendFile(blob,file);
            blob_num += 1;
          }else{
            setTimeout(t);
          }
        },1000);
      }
      xhr.send(form_data);
    }
  }

</script>
</body>
</html>

PHP部分代码

<?php
class Upload{
  private $filepath = './upload'; //上传目录
  private $tmpPath; //PHP文件临时目录
  private $blobNum; //第几个文件块
  private $totalBlobNum; //文件块总数
  private $fileName; //文件名

  public function __construct($tmpPath,$blobNum,$totalBlobNum,$fileName){
    $this->tmpPath = $tmpPath;
    $this->blobNum = $blobNum;
    $this->totalBlobNum = $totalBlobNum;
    $this->fileName = $fileName;

    $this->moveFile();
    $this->fileMerge();
  }

  //判断是否是最后一块，如果是则进行文件合成并且删除文件块
  private function fileMerge(){
    if($this->blobNum == $this->totalBlobNum){
      $blob = '';
      for($i=1; $i<= $this->totalBlobNum; $i++){
        $blob .= file_get_contents($this->filepath.'/'. $this->fileName.'__'.$i);
      }
      file_put_contents($this->filepath.'/'. $this->fileName,$blob);
      $this->deleteFileBlob();
    }
  }

  //删除文件块
  private function deleteFileBlob(){
    for($i=1; $i<= $this->totalBlobNum; $i++){
      @unlink($this->filepath.'/'. $this->fileName.'__'.$i);
    }
  }

  //移动文件
  private function moveFile(){
    $this->touchDir();
    $filename = $this->filepath.'/'. $this->fileName.'__'.$this->blobNum;
    move_uploaded_file($this->tmpPath,$filename);
  }

  //API返回数据
  public function apiReturn(){
    if($this->blobNum == $this->totalBlobNum){
        if(file_exists($this->filepath.'/'. $this->fileName)){
          $data['code'] = 2;
          $data['msg'] = 'success';
          $data['file_path'] = 'http://'.$_SERVER['HTTP_HOST'].dirname($_SERVER['DOCUMENT_URI']).str_replace('.','',$this->filepath).'/'. $this->fileName;
        }
    }else{
        if(file_exists($this->filepath.'/'. $this->fileName.'__'.$this->blobNum)){
          $data['code'] = 1;
          $data['msg'] = 'waiting for all';
          $data['file_path'] = '';
        }
    }
    header('Content-type: application/json');
    echo json_encode($data);
  }

  //建立上传文件夹
  private function touchDir(){
    if(!file_exists($this->filepath)){
      return mkdir($this->filepath);
    }
  }
}

//实例化并获取系统变量传参
$upload = new Upload($_FILES['file']['tmp_name'],$_POST['blob_num'],$_POST['total_blob_num'],$_POST['file_name']);
//调用方法，返回结果
$upload->apiReturn();

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