Download a file from NodeJS Server using Express

Solution 1:

Update

Express has a helper for this to make life easier.

app.get('/download', function(req, res){
  const file = `${__dirname}/upload-folder/dramaticpenguin.MOV`;
  res.download(file); // Set disposition and send it.
});

Old Answer

As far as your browser is concerned, the file's name is just 'download', so you need to give it more info by using another HTTP header.

res.setHeader('Content-disposition', 'attachment; filename=dramaticpenguin.MOV');

You may also want to send a mime-type such as this:

res.setHeader('Content-type', 'video/quicktime');

If you want something more in-depth, here ya go.

var path = require('path');
var mime = require('mime');
var fs = require('fs');

app.get('/download', function(req, res){

  var file = __dirname + '/upload-folder/dramaticpenguin.MOV';

  var filename = path.basename(file);
  var mimetype = mime.lookup(file);

  res.setHeader('Content-disposition', 'attachment; filename=' + filename);
  res.setHeader('Content-type', mimetype);

  var filestream = fs.createReadStream(file);
  filestream.pipe(res);
});

You can set the header value to whatever you like. In this case, I am using a mime-type library - node-mime, to check what the mime-type of the file is.

Another important thing to note here is that I have changed your code to use a readStream. This is a much better way to do things because using any method with 'Sync' in the name is frowned upon because node is meant to be asynchronous.

Solution 2:

Use res.download()

It transfers the file at path as an “attachment”. For instance:

var express = require('express');
var router = express.Router();

// ...

router.get('/:id/download', function (req, res, next) {
    var filePath = "/my/file/path/..."; // Or format the path using the `id` rest param
    var fileName = "report.pdf"; // The default name the browser will use

    res.download(filePath, fileName);    
});

• Read more about res.download()

Solution 3:

For static files like pdfs, Word docs, etc. just use Express's static function in your config:

// Express config
var app = express().configure(function () {
    this.use('/public', express.static('public')); // <-- This right here
});

And then just put all your files inside that 'public' folder, for example:

/public/docs/my_word_doc.docx

And then a regular old link will allow the user to download it:

<a href="public/docs/my_word_doc.docx">My Word Doc</a>

Solution 4:

Here's how I do it:

1. create file
2. send file to client
3. remove file

Code:

let fs = require('fs');
let path = require('path');

let myController = (req, res) => {
  let filename = 'myFile.ext';
  let absPath = path.join(__dirname, '/my_files/', filename);
  let relPath = path.join('./my_files', filename); // path relative to server root

  fs.writeFile(relPath, 'File content', (err) => {
    if (err) {
      console.log(err);
    }
    res.download(absPath, (err) => {
      if (err) {
        console.log(err);
      }
      fs.unlink(relPath, (err) => {
        if (err) {
          console.log(err);
        }
        console.log('FILE [' + filename + '] REMOVED!');
      });
    });
  });
};