Change the file name on the fly for downloading - node.js

Question

I am saving user uploads by renaming it's original name to userID + '_' + new Date().getTime() + fileExt. I am storing the file properties in mongodb collections as :
{
name : String //generated name
, originalName : String //its original name
...
}
Now when the user requests for downloading of file I have to provide the file with its original name (which is persisted in db so no problem to grab it) to the user.
For the following request
GET /users/:userId/uploads/:fileId?type=download
I have this handler
//the mongoose query
UserUpload.findById(req.params.fileId).exec(function(err, doc){
var fileLocation = __dirname + '/public/uploads/users/' + req.params.userId + '/' + doc.name;
if(req.query.type && req.query.type == 'download') {
// I don't know what should I do now
// Downloader.download(fileLocation, newName);
}
});
I read wiki of node-static module but could not figure out how to do that job?

Answer 1

I found the answer here : Download a file from NodeJS Server using Express . Both using express and without using express.
It is too simple if you are using Express. Here is the documentation for res.download. I can't believe that the solution is just one line of code :
res.download('/path/to/file.ext', 'newname.ext');

Answer 2

Here what I use in one of my project, smil is a type of file I need to download, nevermind it.
In that project I have DOWNLOAD_DIR as global variable, which contain the full path to the download folder.
It may make a lot of people cringe (especcially the fileExistSync) but it s a start.
var DOWNLOAD_DIR = '/path/to/download',
url = require('url'),
http = require('http'),
/*
download
IN_:
file_url, url of the file to download
OUT:
file_name, full path to downloaded file, null if the file cound t be downloaded.
COM:
download a file, the file name will be the last part of the url (http://why.so/serious.txt => serious.txt).
WARNING: Do NOT follow redirections.
*/
function download(file_url, callback) {
var options = {host: url.parse(file_url).host, port: 80, path: url.parse(file_url).pathname},
file_name = url.parse(file_url).pathname.split('/').pop(),
//Creating the file
file = fs.createWriteStream(DOWNLOAD_DIR + file_name, {flags: 'w', encoding: 'binary'});
console.log('Downloading file from ' + file_url);
console.log('\tto ' + file_name);
http.get(options, function (res) {
res.pipe(file, {end: 'false'});
//When the file is complete
res.on('end', function () {
//Closing the file
file.end();
console.log('\t\tDownloaded '+ file_name);
callback(DOWNLOAD_DIR + file_name);
});
});
process.on('uncaughtException', function(err) {
console.log('Can t download ' + file_url + '\t(' + err + ')', false);
callback(null);
});
}
/*
download_smil
IN_:
file_url, url of the file to download
OUT:
file_name, full path to downloaded file
COM:
Follow http redirection and then call download function to download it.
You can modify the cad function to use custom names.
*/
function download_smil(file_url, callback) {
function cad(link, callback) {
//Does the file already exist?
var file = url.parse(link).pathname.substr(url.parse(link).pathname.lastIndexOf('/') + 1),
pkmn;
pkmn = fs.existsSync(DOWNLOAD_DIR + '/' + file);
if (pkmn) {
//YES: callback
console.log('File ' + file + ' already exist, skipping');
callback(DOWNLOAD_DIR + file, true);
} else {
//NO: Download it
console.log('Will download ' + link);
download(link, callback);
}
}
//GET the page
http.get(file_url, function (res) {
var link;
//console.log('res.statusCode = ' + res.statusCode + ' res.headers.location = ' + res.headers.location);
//Check if it is a redirect
if (res.statusCode > 300 && res.statusCode < 400 && res.headers.location) {
//console.log('redirect');
//Check if the hostname is in the location
if (url.parse(res.headers.location).hostname) {
//console.log('The link to the smil is res.headers.location');
link = res.headers.location;
cad(link, callback);
} else {
//console.log('The link to the smil is url_parse(file_url).hostname + res.headers.location = ' + url_parse(file_url).hostname + res.headers.location);
link = url_parse(file_url).hostname + res.headers.location;
cad(link, callback);
}
} else {
//console.log('The url is good : ' + file_url);
cad(file_url, callback);
}
});
}