js+分块上传文件

// 文件分块大小（例如1MB）
const chunkSize = 1024 * 1024;

// 上传文件
function uploadFile(file) {
  const totalChunks = Math.ceil(file.size / chunkSize);
  let currentChunk = 0;

  function uploadNextChunk() {
    if (currentChunk >= totalChunks) {
      console.log('Upload complete');
      return;
    }

    const start = currentChunk * chunkSize;
    const end = Math.min(file.size, start + chunkSize);
    const chunk = file.slice(start, end);

    const formData = new FormData();
    formData.append('file', chunk);
    formData.append('chunkIndex', currentChunk);
    formData.append('totalChunks', totalChunks);
    formData.append('fileName', file.name);

    fetch('/upload', {
      method: 'POST',
      body: formData
    })
    .then(response => response.json())
    .then(data => {
      console.log(`Chunk ${currentChunk} uploaded`);
      currentChunk++;
      uploadNextChunk();
    })
    .catch(error => {
      console.error('Error uploading chunk', error);
    });
  }

  uploadNextChunk();
}

// 选择文件并上传
document.getElementById('fileInput').addEventListener('change', (event) => {
  const file = event.target.files[0];
  if (file) {
    uploadFile(file);
  }
});

const express = require('express');
const multer = require('multer');
const fs = require('fs');
const path = require('path');

const app = express();
const upload = multer({ dest: 'uploads/' });

app.post('/upload', upload.single('file'), (req, res) => {
  const { chunkIndex, totalChunks, fileName } = req.body;
  const tempFilePath = path.join('uploads', `${fileName}.part${chunkIndex}`);
  fs.renameSync(req.file.path, tempFilePath);

  if (parseInt(chunkIndex) === parseInt(totalChunks) - 1) {
    const finalFilePath = path.join('uploads', fileName);
    const writeStream = fs.createWriteStream(finalFilePath);
    for (let i = 0; i < totalChunks; i++) {
      const partFilePath = path.join('uploads', `${fileName}.part${i}`);
      const readStream = fs.createReadStream(partFilePath);
      readStream.pipe(writeStream, { end: false });
      readStream.on('end', () => {
        fs.unlinkSync(partFilePath);
      });
    }
    writeStream.on('finish', () => {
      res.json({ message: 'File uploaded successfully' });
    });
  } else {
    res.json({ message: 'Chunk uploaded successfully' });
  }
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});