使用node.js下载从EC2实例下载AWS S3文件

Question

我正在尝试从我的node.js托管应用程序从Amazon S3桶下载文件。

var folderpath= process.env.HOME || process.env.USERPROFILE  // tried using os.homedir() also
var filename  =  'ABC.jpg';
var filepath = 'ABC';
 AWS.config.update({
    accessKeyId: "XXX",
    secretAccessKey: "XXX",
    region: 'ap-southeast-1'
 });
  var DOWNLOAD_DIR = path.join(folderpath, 'Downloads/');
    var s3 = new AWS.S3();
    var s3Params = {Bucket: filepath,Key: filename, };
    var file = require('fs').createWriteStream(DOWNLOAD_DIR+ filename);
    s3.getObject(s3Params).createReadStream().pipe(file);

此代码在localhost上工作正常，但不起作用，因为在实例上，folderpath返回"/home/ec2-user"，而不是下载路径的用户计算机文件夹，即" c： users name"之类的东西。/p>

请建议我如何将文件下载到用户的计算机上？如何从EC2实例获取用户主目录的路径？

谢谢。

Answer 1

您可以使用Express创建HTTP服务器和API。您可以从Express.js开始找到许多教程。在完成Express.js的初始设置后，您可以在Node.js代码中执行类似的操作：

AWS.config.update({
   accessKeyId: "XXX",
   secretAccessKey: "XXX",
   region: 'ap-southeast-1'
});
var s3 = new AWS.S3();
app.get('/download', function(req, res){
  var filename = 'ABC.jpg';
  var filepath = 'ABC';
  var s3Params = {Bucket: filepath, Key: filename};
  var mimetype = 'video/quicktime'; // or whatever is the file type, you can use mime module to find type
  res.setHeader('Content-disposition', 'attachment; filename=' + filename);
  res.setHeader('Content-type', mimetype);
  // Here we are reading the file from S3, creating the read stream and piping it to the response.
  // I'm not sure if this would work or not, but that's what you need: Read from S3 as stream and pass as stream to response (using pipe(res)).
  s3.getObject(s3Params).createReadStream().pipe(res);
});

完成此操作后，您可以调用此API /download，然后在用户的计算机上下载文件。根据您在前端使用的框架或库（或普通的JavaScript），您可以使用此/download API下载文件。只是Google，如何使用XYZ（框架）下载文件。