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How to download a file from node server(using only node modules, no express, etc)

Im currently writing a handler for a download feature. When the user clicks on the download button from his\her browser the download handler is called, which will then initiate the download(mp3 files only). I had this working on php, but I have since changed everything on my project to Node and I can't seem to get this last part working on Node.
This is the php code I had working before:
<?php
header("Content-Type: application/octet-stream");
header("Content-Disposition: attachment; filename=".($_GET['title']));
readfile($_GET['path']);
?>
This is the the new code for Node:
function download(response, request){
var body = [];
request.on('data', function(chunk) {
body.push(chunk);
});
request.on('end', function() {
body = Buffer.concat(body).toString();
var data = qs.parse(body);
var title = data.songTitle;
var filePath = __dirname + "/../myproject/songs/"+title+".mp3";
fs.open(filePath,'r',function(err, fd){
if(!err){
fs.readFile(fd, function(err, data){
if(!err){
var rs = fs.createReadStream(filePath);
response.writeHead(200, {"Content-Type": "application/octet-stream",
"Content-Disposition": "attachment; filename="+title+".mp3",
"Content-Length" : data.length});
rs.pipe(response);
response.on("end",function(){
fs.close(fd);
});
}else{
console.log("Error while trying to read: ", err);
}
});
}else{
console.log("Error could not open: ", err);
}
});
});
When trying to download, I do not get any errors but nothing happens. I have also tried "audio/mpeg3" for content-type, and nothing. Any ideas on what's going on? I'm trying to do this without using third-party modules.
Please note that the function download in not passed as the callback function of http.createServer(). So the order of response and request is not the issue :)

It looks like you switched request and response. Also, instead of using fs.open()/fs.readFile() to determine file size, you can use fs.stat(), which should be much more resource-friendly (since it doesn't require loading the entire file into memory first):
function download(request, response) {
var body = [];
request.on('data', function(chunk) {
body.push(chunk);
});
request.on('end', function() {
var data = qs.parse(Buffer.concat(body).toString());
var title = data.songTitle;
var filePath = title + '.mp3';
fs.stat(filePath, function(err, stats) {
if (err) {
response.statusCode = 500;
return response.end();
}
response.writeHead(200, {
"Content-Type" : "application/octet-stream",
"Content-Disposition" : "attachment; filename="+title+".mp3",
"Content-Length" : stats.size,
});
fs.createReadStream(filePath).pipe(response);
});
});
}

memory error in node JS (node::smalloc::Alloc)

I'm new to node Js, I've build a really simple server that send me back a zip file I request. It's all working but after some request a crash occur and i visualize this message on the terminal :
FATAL ERROR: node::smalloc::Alloc(v8::Handle, size_t, v8::ExternalArrayType) Out Of Memory
var http = require('http');
var url = require('url');
var fs = require('fs');
var port = 1337;
// create http server
var server = http.createServer(function (request, response) {
var path = require('url').parse(request.url, true);
console.log('requested ' + path.pathname);
//get zipped resoures
if (path.pathname == '/getzip') {
console.log(request.url);
var queryData = url.parse(request.url, true).query;
if (queryData.name) {
var filename = queryData.name;
//open corrisponding file
var zipFile = fs.readFileSync('packets/' + filename);
response.writeHead(200, {
'Content-Type': 'application/x-zip',
'Content-disposition': 'attachment; filename=data.zip'
});
//send file in response
response.end(zipFile);
}
else {
response.writeHead(200, {'Content-Type': 'text/plain'});
response.end('{error = "bad url"}');
}
}
}).listen(port);
server.timeout = 1000000;
Do you have any idea of what it can be? this code looks so simple.

Instead of reading the entire file into memory, you should leverage streams for this:
response.writeHead(200, {
'Content-Type' : 'application/x-zip',
'Content-disposition' : 'attachment; filename=data.zip'
});
fs.createReadStream('packets/' + filename).pipe(response);

node.js redirection not working to add username

I am working on a Team Treehouse project that builds a dynamic website with Node.js. The user enters in a username into the search field and it displays the user's avatar, number of badges earned and the number of JavaScript points. For some reason when I enter in the user name and click search the page just goes blank. I think there might be something wrong with the 303 redirection in my router.js file. I'm still fairly new to coding so any insight would be very helpful. Here are each of my js files.
/*****app.js file******/
var router = require('./router.js');
//Problem: We need a simple way to look at a user's badge count and JavaScript points from a web browser
//Solution: Use Node.js to perform the profile look ups and serve our templates via HTTP
//Create a web server
var http = require('http');
http.createServer(function (request, response) {
router.home(request, response);
router.user(request, response);
}).listen(3000);
console.log('Server running at http://<workspace-url>');
/*****router.js file******/
var Profile = require("./profile.js");
var renderer = require('./renderer');
var querystring = require('querystring');
var commonHeader = {'Content-Type': 'text/html'};
// Handle the HTTP route GET / and POST / i.e. Home
function home(request, response) {
//if url == "/" && GET
if (request.url === '/'){
if (request.method.toLowerCase() === "get") {
//show search
console.log(request.url);
response.writeHead(200, commonHeader);
renderer.view('header', {}, response);
renderer.view('search', {}, response);
renderer.view('footer', {}, response);
response.end();
}
else {
//if url == "/" && POST
//get the post data from body
request.on('data', function(postBody){
//extract the username
var query = querystring.parse(postBody.toString());
//redirect to /:username
response.writeHead(303, {'Location': '/' + query.username });
response.end();
});
}
}
}
// Handle the HTTP route for GET /:username i.e. /chalkers
function user(request, response) {
//if url == "/...."
var username = request.url.replace('/', '');
if(user.name.length > 0){
response.writeHead(200, commonHeader);
renderer.view('header', {}, response);
//get json from Treehouse
var studentProfile = new Profile(username);
//on "end"
studentProfile.on("end", function(profileJSON){
//show profile
//Store the values which we need
var values = {
avatarUrl: profileJSON.gravatar_url,
username: profileJSON.profile_name,
badges: profileJSON.badges.length,
javascriptPoints: profileJSON.points.JavaScript
}
//Simple response
renderer.view('profile', values, response);
renderer.view('footer', {}, response);
response.end();
});
//on "error"
studentProfile.on("error", function(error){
//show error
renderer.view('error', {errorMessage: error.message}, response);
renderer.view('search', {}, response);
renderer.view('footer', {}, response);
response.end();
});
}
}
module.exports.home = home;
module.exports.user = user;
/*****profile.js file*******/
var EventEmitter = require("events").EventEmitter;
var http = require("http");
var util = require("util");
/**
* An EventEmitter to get a Treehouse students profile.
* #param username
* #constructor
*/
function Profile(username) {
EventEmitter.call(this);
profileEmitter = this;
//Connect to the API URL (http://teamtreehouse.com/username.json)
var request = http.get("http://teamtreehouse.com/" + username + ".json", function(response) {
var body = "";
if (response.statusCode !== 200) {
request.abort();
//Status Code Error
profileEmitter.emit("error", new Error("There was an error getting the profile for " + username + ". (" + http.STATUS_CODES[response.statusCode] + ")"));
}
//Read the data
response.on('data', function (chunk) {
body += chunk;
profileEmitter.emit("data", chunk);
});
response.on('end', function () {
if(response.statusCode === 200) {
try {
//Parse the data
var profile = JSON.parse(body);
profileEmitter.emit("end", profile);
} catch (error) {
profileEmitter.emit("error", error);
}
}
}).on("error", function(error){
profileEmitter.emit("error", error);
});
});
}
util.inherits( Profile, EventEmitter );
module.exports = Profile;
/*****renderer.js file*******/
var fs = require('fs');
function mergeValues(values, content) {
//Cycle over the keys
for(var key in values) {
//Replace all the {{key}} with the value from the values object
content = content.replace('{{' + key + '}}', values[key]);
}
//return merged content
return content;
}
function view(templateName, values, response) {
//Read from the template file
var fileContents = fs.readFileSync('./views/' + templateName + '.html', {encoding: 'utf8'});
//Insert values in to the content
fileContents = mergeValues(values, fileContents);
//Write out the contents to the response
response.write(fileContents);
}
module.exports.view = view;

Treehouse changed from http to https and so this example code doesn't work any longer. The reason for that is in the profile.js file. You are making calls for an http site and it doesn't exist. You need to change the code (only in profile.js) to make it connect to the https site instead.
var http = require("http");
should be changed to
var https = require("https");
and with that all references to the variable in your profile.js code should be changed to https.
As well as the hard-coded URL start:
var request = http.get("http://teamtreehous...
should be
var request = https.get("https://teamtreehous...
That should resolve the problem. Good luck!

In order to get your code in the profile.js file to run, you need to change some instances of the "http" module to "https" but, and this is important, not all instances.
What needs to remain http is the the status code error on the profile.js page. This line of code is correct:
profileEmitter.emit("error", new Error("There was an error getting the profile for " + username + ". (" + http.STATUS_CODES[response.statusCode] + ")"));
But all other instances of the http module need to change to https. For example, these lines are correct:
var url = "https://teamtreehouse.com/" + username + ".json";
var request = https.get(url, function(response){
Remember to require both modules at the top of profile.js page
var http = require("http");
var https = require("https");

Node.js request data event not firing. What am I doing wrong?

It seems like the data event on the request object is not firing, or I can't wire it up right in order to get anything from it. I am getting the end event just fine, and all the urls are working. I have looked on forums and documentation, and when I look at my code it seems like it should work. I am using Node version 0.10.12.
I am new. I am trying to get a simple server going in node. I was following The Node Beginner Book. Most of this code comes from there, with some very small modifications. I have already tried the code straight from the book.
Here is the code I am working with now.
index.js
var server = require("./server");
var router = require("./router");
var requestHandlers = require("./requestHandlers");
var handle = {};
handle["/"] = requestHandlers.start;
handle["/start"] = requestHandlers.start;
handle["/upload"] = requestHandlers.upload;
if (process.argv[2] !== undefined && process.argv[2] !== null) {
server.start(router.route, handle, process.argv[2]);
} else {
server.start(router.route, handle);
}
router.js
route = function(handle, pathname, response, postData) {
if (typeof handle[pathname] === "function") {
handle[pathname](response, postData);
} else {
response.writeHead(404, {"Content-Type": "text/plain"});
response.end("404 Not found");
}
}
exports.route = route;
server.js
var http = require('http');
var url = require('url');
var portToUse = 8888;
start = function(route, handle, port) {
if (port !== undefined && port !== null && typeof parseInt(port) === 'number' && port > 1000 && port < 10000) {
console.log('You passed in the port number %d.', port);
portToUse = port;
}
http.createServer(function(request, response) {
var postData = '';
var pathname = url.parse(request.url).pathname;
console.log('Request for %s received.', pathname);
route(handle, pathname, response);
request.setEncoding('utf8');
// I have tried both .on and .addListener
request.on('data', function(postDataChunk) {
postData += postDataChunk;
console.log('Received POST data chunk %s.', postData);
});
request.on('end', function(postDataChunk) {
console.log(postDataChunk);
route(handle, pathname, response, postData);
});
}).listen(portToUse);
console.log('The server listening on %d.', portToUse);
}
exports.start = start;
requestHandlers.js
var exec = require('child_process').exec;
start = function(response, postData) {
var body = '<!doctype html>' +
'<html lang="en">' +
'<head>' +
'<meta charset="UTF-8">' +
'<title>Upload Server</title>' +
'</head>' +
'<body>' +
'<form action="/upload">' +
'<textarea name="text" id="text-area" cols="40" rows="20"></textarea>' +
'<input type="submit" value="Submit text">' +
'</form>' +
'</body>' +
'</html>';
response.writeHead(200, {"Content-Type": "text/html"});
response.end(body);
}
upload = function(response, postData) {
response.writeHead(200, {'Content-Type': 'text/plain'});
response.end('You\'ve sent: ' + postData);
}
exports.start = start;
exports.upload = upload;
Thanks in advance.

You need to add your data listener before you call route. Reason being, in your handlers you are calling response.end. When you do this, node checks if there are any data listeners on the socket, and if not, it will dump the existing request data, as it figures it's no longer needed.

call two file from another with node js

I have a file called node.js:
var net = require('net');
var crypto = require('crypto');
//sjcl
var sjcl = require('./sjcl');
//retrive fb profile
var loadFb = require('./loadFb.js');
var loadFeed = require('./loadFeed.js');
//read json user file
var fs = require('fs');
var text = fs.readFileSync(__dirname + '/users','utf8');
var HOST = 'localhost';
var PORT = 7000;
net.createServer(function(sock) {
// We have a connection - a socket object
console.log('CONNECTED: ' + sock.remoteAddress +':'+ sock.remotePort);
// Add a 'data' event handler to this instance of socket
sock.on('data', function(data) {
console.log('User request profile of: ' + data);
//var date = (data.toString()).split("***");
//var from = date[1];
loadFb(extendetPath, function(pageData)
{
loadFeed(extendetPath2, function(pageData2)
{
var fs = require('fs');
var profileText = fs.readFileSync('/tmp/profile','utf8');
console.log(profileText);
sock.write(profileText);
});
});
});
// Add a 'close' event handler to this instance of socket
sock.on('close', function(data) {
console.log('CLOSED: ' + sock.remoteAddress +' '+ sock.remotePort);
});
}).listen(PORT);
console.log('Server listening on ' + HOST +':'+ PORT);
function returnKeyFromUser(id)
{
//text
var trovata = false;
var dati = JSON.parse(text);
for(var i=0; i<dati.friendlist.friend.length && trovata==false; i++)
{
var user = (dati.friendlist.friend[i].username).replace("\n","");
var userID = (id).replace("\n","");
if(user==userID)
{
trovata=true;
return ((dati.friendlist.friend[i].publicKey).toString()).replace("\n","");
}
}
if(trovata==false)
return null;
}
There is a small http server that receives a facebook username and what he have to do is retrieve 2 page:
a graphapi with the profile information, and a graphapi with the feed informations of a facebook profile
I copy the other two files:
var https = require('https');
module.exports = function(path, callback) {
var options = {
host: 'graph.facebook.com',
port: 443,
path: (path.toString()).replace("\n",""),
method: 'GET'
};
var req = https.get(options, function(res) {
var pageData = "";
if((path.toString()).indexOf("/")==0 && (path.toString()).indexOf("/GET /`HTTP/")!=0)
//for load only (I hope facebook profile)
{
console.log(options);
res.setEncoding('utf8');
res.on('data', function (chunk) {
pageData += chunk;
});
res.on('end', function()
{
var fs = require('fs');
fs.writeFile("/tmp/profile", pageData, function(err) {
if(err) {
console.log(err);
} else {
console.log("The file was saved!");
}
});
//callback(pageData);
return;
});
}
});
};
3° file
var https = require('https');
module.exports = function(path, callback) {
var options = {
host: 'graph.facebook.com',
port: 443,
path: (path.toString()).replace("\n",""),
method: 'GET'
};
var req = https.get(options, function(res) {
var pageData = "";
if((path.toString()).indexOf("/")==0 && (path.toString()).indexOf("/GET / HTTP/")!=0) //for load only (I hope facebook profile)
{
console.log(options);
res.setEncoding('utf8');
res.on('data', function (chunk) {
pageData += chunk;
});
res.on('end', function()
{
var fs = require('fs');
fs.appendFile('/tmp/profile', "***"+pageData, function (err) {
if (err) throw err;
console.log('It\'s saved!');
});
callback(pageData);
});
}
});
};
I don't know If there is a way to call the two file in the first file node.js but what I done is this: (to call from node.js the fist file, and from the second file call the third)
in node.js file I call the first file loadFb.js with this command:
loadFb(extendetPath, function(pageData)
{
This call saves a file on my tmp profile directory and inside I call the other file loadFeed that appends some text.
After that I have to send the entire information to the client but I have a mistake.
In order the nodejs correctly call loadFb and he write tmp - profile, than he call loadFeed
but before appending the information the node call back to the client only the half of informations that I need.
I'm not a good nodejs programmer, this is a work for my thesis.
Can someone help me?

Let's look at the following code:
res.on('end', function()
{
var fs = require('fs');
fs.appendFile('/tmp/profile', "***"+pageData, function (err) {
if (err) throw err;
console.log('It\'s saved!');
});
callback(pageData);
});
What it does it runs the asynchronous method appendFile and immediately after that calls callback. So when the code in the callback is executed, the file is not updated yet. You need to move the callback(pageData); to the appendFile's callback. And you need to review you code keeping this in mind because I see that the same fix should be made in another file so maybe there are some similar places as well.