近期接到的新需求：上传大文件，因文件上传的大小不定，所以需要切片上传

前端代码：

import md5 from "js-md5";/** * 缓存转换  导入大文件 * @param {*} that   this * @param {*} file 上传文件的对象 * @param {*} size   每次上传文件的限制大小 * @param {*} progress 上传文件的进度条 * @param {*} url string 上传文件的url * @param {*} module_name  string   上传文件的需要上文的文件名 */export function uploadFile(that, file, size, progress, url, module_name) {  let xhr = new XMLHttpRequest();  let form_data = new FormData();  let start = 0;  let end = start + that.size;  let blob;  let blob_num = 1;  blob = cutFile(file);  sendFile(blob, file);  blob_num += 1;  //切割文件  function cutFile(file) {    let file_blob = file.slice(start, end);    start = end;    end = start + that.size;    return file_blob;  };  //发送文件  function sendFile(blob, file) {    let total_blob_num = Math.ceil(file.size / size);    form_data = new FormData();    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);    form_data.append('module_name', module_name);    form_data.append('code', md5(md5(file.name + global.ENCRYPTION_KEY)));    xhr.open("POST", global.IMG_URL + url, false);    xhr.onreadystatechange = function () {      if (total_blob_num == 1) {        that.progress = 100;      } else {        that.progress = Math.min(100, (blob_num / total_blob_num) * 100);      }      if (JSON.parse(xhr.response).code == 0) {        that.file_name = '';        that.$Message.error('上传错误');        return false      } else if (JSON.parse(xhr.response).code == 2) {        that.$Message.success('上传成功');        that.file_path = JSON.parse(xhr.response).file_path;        return false      }      let t = setTimeout(function () {        if (start < file.size) {          blob = cutFile(file);          sendFile(blob, file);          blob_num += 1;        } else {          clearTimeout(t);        }      }, 1000);    }    xhr.send(form_data);  }}

后端代码：我们后端是用PHP完成的

     filepath = $fileDir;        $this->tmpPath = $_FILES['file']['tmp_name'];        $this->blobNum = $_POST['blob_num'];        $this->totalBlobNum = $_POST['total_blob_num'];        $this->fileName = $_POST['file_name'];        // 校验        $this->validate($_POST['code'], $_POST['file_name']);        // 移动文件        $this->moveFile();        // 合并分块的文件        $this->fileMerge();        // 响应状态        $this->apiReturn();    }    // 判断是否是最后一块，如果是则进行文件合成并且删除文件块    private function fileMerge()    {        if($this->blobNum == $this->totalBlobNum){            $blob = '';            for($i=1; $i<= $this->totalBlobNum; $i++){                $blob .= file_get_contents($this->filepath.'/'. $this->fileName.'__'.$i);            }            $ext = '.'.substr(strrchr($this->fileName, '.'), 1);            $this->finalFileName = date('YmdHis') . rand('10000', '99999') . $ext;            file_put_contents($this->filepath.'/'. $this->finalFileName,$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()    {        header('Content-type: application/json');        if($this->blobNum == $this->totalBlobNum){            if(file_exists($this->filepath.'/'. $this->finalFileName)){                $data['code'] = 2;                $data['msg'] = 'success';                $data['file_path'] = ltrim($this->filepath,'./').'/'. $this->finalFileName;                echo json_encode($data);                exit;            }        }else{            if(file_exists($this->filepath.'/'. $this->fileName.'__'.$this->blobNum)){                $data['code'] = 1;                $data['msg'] = '上传中，共:'.$this->totalBlobNum.'块，当前第'.$this->blobNum.'块....';                $data['file_path'] = '';                echo json_encode($data);                exit;            }        }    }    // 建立上传文件夹    private function touchDir()    {        if(!file_exists($this->filepath)){            return mkdir($this->filepath, 0777, true);        }    }    // 参数校验    private function validate($code,$fileName)    {        if (md5(md5($fileName.config_item('encryption_key'))) != $code) {            echo_json(0,'参数校验失败');        }    }}function echo_json($code = 0, $msg = '', $data = array()){    $arr = array(        'code' => $code,        'msg' => $msg,        'data' => $data    );    echo json_encode($arr);    exit;}