Develop Reference

Setting the correct content-type in HTML web browser [duplicate]

I have a logo that is residing at the public/images/logo.gif. Here is my nodejs code.
http.createServer(function(req, res){
res.writeHead(200, {'Content-Type': 'text/plain' });
res.end('Hello World \n');
}).listen(8080, '127.0.0.1');
It works but when I request for localhost:8080/logo.gif then I obviously don't get the logo.
What changes I need to do to serve an image.

2016 Update
Examples with Express and without Express that actually work
This question is over 5 years old but every answer has some problems.
TL;DR
Scroll down for examples to serve an image with:
express.static
express
connect
http
net
All of the examples are also on GitHub: https://github.com/rsp/node-static-http-servers
Test results are available on Travis: https://travis-ci.org/rsp/node-static-http-servers
Introduction
After over 5 years since this question was asked there is only one correct answer by generalhenry but even though that answer has no problems with the code, it seems to have some problems with reception. It was commented that it "doesn't explain much other than how to rely on someone else to get the job done" and the fact how many people have voted this comment up clearly shows that a lot of things need clarification.
First of all, a good answer to "How to serve images using Node.js" is not implementing a static file server from scratch and doing it badly. A good answer is using a module like Express that does the job correctly.
Answering comments that say that using Express "doesn't explain much other than how to rely on someone else to get the job done" it should be noted, that using the http module already relies on someone else to get the job done. If someone doesn't want to rely on anyone to get the job done then at least raw TCP sockets should be used instead - which I do in one of my examples below.
A more serious problem is that all of the answers here that use the http module are broken. They introduce race conditions, insecure path resolution that will lead to path traversal vulnerability, blocking I/O that will completely fail to serve any concurrent requests at all and other subtle problems - they are completely broken as examples of what the question asks about, and yet they already use the abstraction that is provided by the http module instead of using TCP sockets so they don't even do everything from scratch as they claim.
If the question was "How to implement static file server from scratch, as a learning exercise" then by all means answers how to do that should be posted - but even then we should expect them to at least be correct. Also, it is not unreasonable to assume that someone who wants to serve an image might want to serve more images in the future so one could argue that writing a specific custom static file server that can serve only one single file with hard-coded path is somewhat shortsighted. It seems hard to imagine that anyone who searches for an answer on how to serve an image would be content with a solution that serves just a single image instead of a general solution to serve any image.
In short, the question is how to serve an image and an answer to that is to use an appropriate module to do that in a secure, performant and reliable way that is readable, maintainable and future-proof while using the best practice of professional Node development. But I agree that a great addition to such an answer would be showing a way to implement the same functionality manually but sadly every attempt to do that has failed so far. And that is why I wrote some new examples.
After this short introduction, here are my five examples doing the job on 5 different levels of abstraction.
Minimum functionality
Every example serves files from the public directory and supports the minimum functionality of:
MIME types for most common files
serves HTML, JS, CSS, plain text and images
serves index.html as a default directory index
responds with error codes for missing files
no path traversal vulnerabilities
no race conditions while reading files
I tested every version on Node versions 4, 5, 6 and 7.
express.static
This version uses the express.static built-in middleware of the express module.
This example has the most functionality and the least amount of code.
var path = require('path');
var express = require('express');
var app = express();
var dir = path.join(__dirname, 'public');
app.use(express.static(dir));
app.listen(3000, function () {
console.log('Listening on http://localhost:3000/');
});
express
This version uses the express module but without the express.static middleware. Serving static files is implemented as a single route handler using streams.
This example has simple path traversal countermeasures and supports a limited set of most common MIME types.
var path = require('path');
var express = require('express');
var app = express();
var fs = require('fs');
var dir = path.join(__dirname, 'public');
var mime = {
html: 'text/html',
txt: 'text/plain',
css: 'text/css',
gif: 'image/gif',
jpg: 'image/jpeg',
png: 'image/png',
svg: 'image/svg+xml',
js: 'application/javascript'
};
app.get('*', function (req, res) {
var file = path.join(dir, req.path.replace(/\/$/, '/index.html'));
if (file.indexOf(dir + path.sep) !== 0) {
return res.status(403).end('Forbidden');
}
var type = mime[path.extname(file).slice(1)] || 'text/plain';
var s = fs.createReadStream(file);
s.on('open', function () {
res.set('Content-Type', type);
s.pipe(res);
});
s.on('error', function () {
res.set('Content-Type', 'text/plain');
res.status(404).end('Not found');
});
});
app.listen(3000, function () {
console.log('Listening on http://localhost:3000/');
});
connect
This version uses the connect module which is a one level of abstraction lower than express.
This example has similar functionality to the express version but using slightly lower-lever APIs.
var path = require('path');
var connect = require('connect');
var app = connect();
var fs = require('fs');
var dir = path.join(__dirname, 'public');
var mime = {
html: 'text/html',
txt: 'text/plain',
css: 'text/css',
gif: 'image/gif',
jpg: 'image/jpeg',
png: 'image/png',
svg: 'image/svg+xml',
js: 'application/javascript'
};
app.use(function (req, res) {
var reqpath = req.url.toString().split('?')[0];
if (req.method !== 'GET') {
res.statusCode = 501;
res.setHeader('Content-Type', 'text/plain');
return res.end('Method not implemented');
}
var file = path.join(dir, reqpath.replace(/\/$/, '/index.html'));
if (file.indexOf(dir + path.sep) !== 0) {
res.statusCode = 403;
res.setHeader('Content-Type', 'text/plain');
return res.end('Forbidden');
}
var type = mime[path.extname(file).slice(1)] || 'text/plain';
var s = fs.createReadStream(file);
s.on('open', function () {
res.setHeader('Content-Type', type);
s.pipe(res);
});
s.on('error', function () {
res.setHeader('Content-Type', 'text/plain');
res.statusCode = 404;
res.end('Not found');
});
});
app.listen(3000, function () {
console.log('Listening on http://localhost:3000/');
});
http
This version uses the http module which is the lowest-level API for HTTP in Node.
This example has similar functionality to the connect version but using even more lower-level APIs.
var path = require('path');
var http = require('http');
var fs = require('fs');
var dir = path.join(__dirname, 'public');
var mime = {
html: 'text/html',
txt: 'text/plain',
css: 'text/css',
gif: 'image/gif',
jpg: 'image/jpeg',
png: 'image/png',
svg: 'image/svg+xml',
js: 'application/javascript'
};
var server = http.createServer(function (req, res) {
var reqpath = req.url.toString().split('?')[0];
if (req.method !== 'GET') {
res.statusCode = 501;
res.setHeader('Content-Type', 'text/plain');
return res.end('Method not implemented');
}
var file = path.join(dir, reqpath.replace(/\/$/, '/index.html'));
if (file.indexOf(dir + path.sep) !== 0) {
res.statusCode = 403;
res.setHeader('Content-Type', 'text/plain');
return res.end('Forbidden');
}
var type = mime[path.extname(file).slice(1)] || 'text/plain';
var s = fs.createReadStream(file);
s.on('open', function () {
res.setHeader('Content-Type', type);
s.pipe(res);
});
s.on('error', function () {
res.setHeader('Content-Type', 'text/plain');
res.statusCode = 404;
res.end('Not found');
});
});
server.listen(3000, function () {
console.log('Listening on http://localhost:3000/');
});
net
This version uses the net module which is the lowest-level API for TCP sockets in Node.
This example has some of the functionality of the http version but the minimal and incomplete HTTP protocol has been implemented from scratch. Since it doesn't support chunked encoding it loads the files into memory before serving them to know the size before sending a response because statting the files and then loading would introduce a race condition.
var path = require('path');
var net = require('net');
var fs = require('fs');
var dir = path.join(__dirname, 'public');
var mime = {
html: 'text/html',
txt: 'text/plain',
css: 'text/css',
gif: 'image/gif',
jpg: 'image/jpeg',
png: 'image/png',
svg: 'image/svg+xml',
js: 'application/javascript'
};
var server = net.createServer(function (con) {
var input = '';
con.on('data', function (data) {
input += data;
if (input.match(/\n\r?\n\r?/)) {
var line = input.split(/\n/)[0].split(' ');
var method = line[0], url = line[1], pro = line[2];
var reqpath = url.toString().split('?')[0];
if (method !== 'GET') {
var body = 'Method not implemented';
con.write('HTTP/1.1 501 Not Implemented\n');
con.write('Content-Type: text/plain\n');
con.write('Content-Length: '+body.length+'\n\n');
con.write(body);
con.destroy();
return;
}
var file = path.join(dir, reqpath.replace(/\/$/, '/index.html'));
if (file.indexOf(dir + path.sep) !== 0) {
var body = 'Forbidden';
con.write('HTTP/1.1 403 Forbidden\n');
con.write('Content-Type: text/plain\n');
con.write('Content-Length: '+body.length+'\n\n');
con.write(body);
con.destroy();
return;
}
var type = mime[path.extname(file).slice(1)] || 'text/plain';
var s = fs.readFile(file, function (err, data) {
if (err) {
var body = 'Not Found';
con.write('HTTP/1.1 404 Not Found\n');
con.write('Content-Type: text/plain\n');
con.write('Content-Length: '+body.length+'\n\n');
con.write(body);
con.destroy();
} else {
con.write('HTTP/1.1 200 OK\n');
con.write('Content-Type: '+type+'\n');
con.write('Content-Length: '+data.byteLength+'\n\n');
con.write(data);
con.destroy();
}
});
}
});
});
server.listen(3000, function () {
console.log('Listening on http://localhost:3000/');
});
Download examples
I posted all of the examples on GitHub with more explanation.
Examples with express.static, express, connect, http and net:
https://github.com/rsp/node-static-http-servers
Other project using only express.static:
https://github.com/rsp/node-express-static-example
Tests
Test results are available on Travis:
https://travis-ci.org/rsp/node-static-http-servers
Everything is tested on Node versions 4, 5, 6, and 7.
See also
Other related answers:
Failed to load resource from same directory when redirecting Javascript
onload js call not working with node
Sending whole folder content to client with express
Loading partials fails on the server JS
Node JS not serving the static image

I agree with the other posters that eventually, you should use a framework, such as Express.. but first you should also understand how to do something fundamental like this without a library, to really understand what the library abstracts away for you.. The steps are
Parse the incoming HTTP request, to see which path the user is asking for
Add a pathway in conditional statement for the server to respond to
If the image is requested, read the image file from the disk.
Serve the image content-type in a header
Serve the image contents in the body
The code would look something like this (not tested)
fs = require('fs');
http = require('http');
url = require('url');
http.createServer(function(req, res){
var request = url.parse(req.url, true);
var action = request.pathname;
if (action == '/logo.gif') {
var img = fs.readFileSync('./logo.gif');
res.writeHead(200, {'Content-Type': 'image/gif' });
res.end(img, 'binary');
} else {
res.writeHead(200, {'Content-Type': 'text/plain' });
res.end('Hello World \n');
}
}).listen(8080, '127.0.0.1');

You should use the express framework.
npm install express
and then
var express = require('express');
var app = express();
app.use(express.static(__dirname + '/public'));
app.listen(8080);
and then the URL localhost:8080/images/logo.gif should work.

var http = require('http');
var fs = require('fs');
http.createServer(function(req, res) {
res.writeHead(200,{'content-type':'image/jpg'});
fs.createReadStream('./image/demo.jpg').pipe(res);
}).listen(3000);
console.log('server running at 3000');

It is too late but helps someone, I'm using node version v7.9.0 and express version 4.15.0
if your directory structure is something like this:
your-project
uploads
package.json
server.js
server.js code:
var express = require('express');
var app = express();
app.use(express.static(__dirname + '/uploads'));// you can access image
//using this url: http://localhost:7000/abc.jpg
//make sure `abc.jpg` is present in `uploads` dir.
//Or you can change the directory for hiding real directory name:
`app.use('/images', express.static(__dirname+'/uploads/'));// you can access image using this url: http://localhost:7000/images/abc.jpg
app.listen(7000);

Vanilla node version as requested:
var http = require('http');
var url = require('url');
var path = require('path');
var fs = require('fs');
http.createServer(function(req, res) {
// parse url
var request = url.parse(req.url, true);
var action = request.pathname;
// disallow non get requests
if (req.method !== 'GET') {
res.writeHead(405, {'Content-Type': 'text/plain' });
res.end('405 Method Not Allowed');
return;
}
// routes
if (action === '/') {
res.writeHead(200, {'Content-Type': 'text/plain' });
res.end('Hello World \n');
return;
}
// static (note not safe, use a module for anything serious)
var filePath = path.join(__dirname, action).split('%20').join(' ');
fs.exists(filePath, function (exists) {
if (!exists) {
// 404 missing files
res.writeHead(404, {'Content-Type': 'text/plain' });
res.end('404 Not Found');
return;
}
// set the content type
var ext = path.extname(action);
var contentType = 'text/plain';
if (ext === '.gif') {
contentType = 'image/gif'
}
res.writeHead(200, {'Content-Type': contentType });
// stream the file
fs.createReadStream(filePath, 'utf-8').pipe(res);
});
}).listen(8080, '127.0.0.1');

I like using Restify for REST services. In my case, I had created a REST service to serve up images and then if an image source returned 404/403, I wanted to return an alternative image. Here's what I came up with combining some of the stuff here:
function processRequest(req, res, next, url) {
var httpOptions = {
hostname: host,
path: url,
port: port,
method: 'GET'
};
var reqGet = http.request(httpOptions, function (response) {
var statusCode = response.statusCode;
// Many images come back as 404/403 so check explicitly
if (statusCode === 404 || statusCode === 403) {
// Send default image if error
var file = 'img/user.png';
fs.stat(file, function (err, stat) {
var img = fs.readFileSync(file);
res.contentType = 'image/png';
res.contentLength = stat.size;
res.end(img, 'binary');
});
} else {
var idx = 0;
var len = parseInt(response.header("Content-Length"));
var body = new Buffer(len);
response.setEncoding('binary');
response.on('data', function (chunk) {
body.write(chunk, idx, "binary");
idx += chunk.length;
});
response.on('end', function () {
res.contentType = 'image/jpg';
res.send(body);
});
}
});
reqGet.on('error', function (e) {
// Send default image if error
var file = 'img/user.png';
fs.stat(file, function (err, stat) {
var img = fs.readFileSync(file);
res.contentType = 'image/png';
res.contentLength = stat.size;
res.end(img, 'binary');
});
});
reqGet.end();
return next();
}

This may be a bit off-topic, since you are asking about static file serving via Node.js specifically (where fs.createReadStream('./image/demo.jpg').pipe(res) is actually a good idea), but in production you may want to have your Node app handle tasks, that cannot be tackled otherwise, and off-load static serving to e.g Nginx.
This means less coding inside your app, and better efficiency since reverse proxies are by design ideal for this.

This method works for me, it's not dynamic but straight to the point:
const fs = require('fs');
const express = require('express');
const app = express();
app.get( '/logo.gif', function( req, res ) {
fs.readFile( 'logo.gif', function( err, data ) {
if ( err ) {
console.log( err );
return;
}
res.write( data );
return res.end();
});
});
app.listen( 80 );

Let me just add to the answers above, that optimizing images, and serving responsive images helps page loading times dramatically since >90% of web traffic are images. You might want to pre-process images using JS / Node modules such as imagemin and related plug-ins, ideally during the build process with Grunt or Gulp.
Optimizing images means processing finding an ideal image type, and selecting optimal compression to achieve a balance between image quality and file size.
Serving responsive images translates into creating several sizes and formats of each image automatically and using srcset in your HTML allows you to serve optimal image set (that is, the ideal format and dimensions, thus optimal file size) for every single browser).
Image processing automation during the build process means incorporating it up once, and presenting optimized images further on, requiring minimum extra time.
Some great read on responsive images, minification in general, imagemin node module and using srcset.

//This method involves directly integrating HTML Code in the res.write
//first time posting to stack ...pls be kind
const express = require('express');
const app = express();
const https = require('https');
app.get("/",function(res,res){
res.write("<img src="+image url / src +">");
res.send();
});
app.listen(3000, function(req, res) {
console.log("the server is onnnn");
});

import http from "node:http";
import fs from "node:fs";
const app = http.createServer((req, res)=>{
if(req.url === "/" && req.method === "GET"){
res.writeHead(200, {
"Content-Type" : "image/jpg"
})
fs.readFile("sending.jpg", (err, data)=>{
if(err){
throw err;
}else{
res.write(data);
res.end();
}
})
}
}).listen(8080, ()=>{
console.log(8080)
})

request.url showing two urls in node.js

I am getting two urls in req.url in http.creatServer() function.
If i console the current url it shows "/favicon.io" and "/test.txt".
I want to show the file "text.txt" content when user try to open the url "http://localhost:3000/test.txt".
Here is my code
var fs = require('fs');
var PORT = process.env.PORT || 3000;
var http = require('http');
http.createServer(function(req,res){
res.writeHead(200, {'Content-type' : 'text/plain'});
console.log('----',req.url);
if(req.url === "/test.txt"){
fs.createReadStream(__dirname + "/test.txt").pipe(res);
}
else
{
res.end('Hello World!!');
}
}).listen(PORT);
console.log('Server Running at port ' + PORT);

Ohh..got your problem.
Node is Asynchronous event driven programming language.
so It wont wait unit the file content being read by request operation.
It will execute another request and your another request is favicon in pipeline.
so it will always return false. so that you will getting hello world every time.
use this and check
if('txt' == req.url.split('.')[1]){
var read = fs.readFileSync(__dirname + "/test.txt");
res.end(read.toString());
}

Node.js file server with file index

I have the below code for a file server and I would like to use and html page to show an index of the files that are available for download in the static folder "public1"
I currently can serve an html page if the user explicitly requests it but I can't make it automatically serve the html page. The commented out code is my attempt at serving the html page named "hello" by default. It doesn't work...
How can I make the html page display (by default) to the user that navigates to the ip address in a browser?
How can I make the html file show an index of files in the static folder?
So for this two part question, does anyone know how to do this? Can you point me in the right direction.
var express = require('express');
var server = express();
var port = 10001;
//server.get(__dirname + 'public1', function(req, res) {
// res.send('Hello.html');
//});
server.use(express.static(__dirname + '/public1'));
server.listen(port, function() {
console.log('server listening on port ' + port);
});

The easiest way to do this is by using the serve-index and serve-static middleware that is available for express. The below example code works, just swap out the process.cwd() for whatever directory you'd like to serve.
const express = require('express');
const serveIndex = require('serve-index');
const serveStatic = require('serve-static');
const path = require('path');
const server = express();
const port = process.env.PORT || 3000;
function setHeaders(res, filepath) {
res.setHeader('Content-Disposition', 'attachment; filename=' + path.basename(filepath));
}
const dirToServe = process.cwd();
server.use('/', serveIndex(dirToServe, {icons: true}));
server.use('/', serveStatic(dirToServe, {setHeaders: setHeaders}));
server.listen(port, () => {
console.log('listening on port ' + port);
});

Manipulating Cookies before serving

Scenario
I have a simple NodeJS server using the Express framework. I have some ReactJS pages that I need to serve. No Isomorphic for now.
Before serving, I want to check if the user has a particular cookie and then based on that I want to create a new cookie.
What I tried
Here is the code for my server.js file.
var express = require("express");
var app = express();
var Cookies = require("cookies");
app.use(function(req, res){
var cookies = new Cookies( req, res);
var userCookie = cookies.get("sso");
var isLoggedIn = cookies.get("isLoggedIn");
if(userCookie !== undefined && isLoggedIn === false){
cookies.set("isLoggedIn", true);
}
});
app.use(express.static(__dirname + '/build'));
var port = process.env.PORT || 8080;
app.listen(port, function() {
console.log("Listening on " + port);
});
So I am using express.static for serving static files from my build folder.
I tried moving the app.use(express.static(__dirname + '/build')); line above the previous app.use, but then the code never enters the cookies section.
I tried this simple thing. Even this didn't worked. I can see log hello, but the website isn't working.
var express = require("express");
var app = express();
app.use(function(req, res){
console.log("hello");
});
app.use(express.static(__dirname + '/build'));
var port = process.env.PORT || 8080;
app.listen(port, function() {
console.log("Listening on " + port);
});

There's a problem with your use of cookies. You're checking if isLoggedIn, the cookie value, === false, a boolean value. But cookies are always strings, so the comparison will always be false and you'll never set isLoggedIn to "true".
If your update your code to treat the values as strings it might work. Try something like this:
if(userCookie !== undefined && isLoggedIn !== "true"){
cookies.set("isLoggedIn", "true");
}

As jeremy's answer pointed out, I was using the cookies the wrong way. But that wasn't the core problem. If code would have run, express server would have thrown error. The real problem was that i wasn't calling the next middleware in the application’s request-response cycle. According to the docs
Middleware is a function with access to the request object (req), the
response object (res), and the next middleware in the application’s
request-response cycle, commonly denoted by a variable named next.
I wasn't calling the next.
So the updated running code is:
var express = require("express");
var app = express();
var Cookies = require("cookies");
app.use(function(req, res, next){
var cookies = new Cookies( req, res);
var userCookie = cookies.get("sso");
var isLoggedIn = cookies.get("isLoggedIn");
if(userCookie !== undefined && isLoggedIn !== "true"){
cookies.set("isLoggedIn", "true",{ httpOnly: false } );
}
next();
});
app.use(express.static(__dirname + '/build'));
var port = process.env.PORT || 8142;
app.listen(port, function() {
console.log("Listening on " + port);
});

Node JS Express all requests showing 404

All requests are showing GET / 404 8.128 ms-13 in console.
I have posted the code below, there is no error in the code. I can run other NodeJS applications. But this is showing 404 in console. It is not even showing the fav icon. It worked once showing Cannot GET / error and the fav icon was visible at that time.
'use strict';
var express = require('express');
var app = express();
var bodyParser = require('body-parser');
var favicon = require('serve-favicon');
var logger = require('morgan');
var port = process.env.PORT || 8001;
var four0four = require('./utils/404')();
var environment = process.env.NODE_ENV;
app.use(favicon(__dirname + '/favicon.ico'));
app.use(bodyParser.urlencoded({extended: true}));
app.use(bodyParser.json());
app.use(logger('dev'));
app.use('/api', require('./routes'));
console.log('About to crank up node');
console.log('PORT=' + port);
console.log('NODE_ENV=' + environment);
switch (environment){
default:
console.log('** DEV **');
app.use(express.static('./src/client/'));
app.use(express.static('./'));
app.use(express.static('./tmp'));
app.use('/app/*', function(req, res, next) {
four0four.send404(req, res);
});
app.use('/*', express.static('./src/client/index.html'));
break;
}
app.listen(port, function() {
console.log('Express server listening on port ' + port);
console.log('env = ' + app.get('env') +
'\n__dirname = ' + __dirname +
'\nprocess.cwd = ' + process.cwd());
});

According to http://expressjs.com/starter/static-files.html I think that your route here app.use('/*', express.static('./src/client/index.html')); will use ./src/client/index.html as the base path and append whatever you provide to find a file. For example
/some-file will look for ./src/client/index.html/some-file which is obviously not existed
In case you want to understand it more, the static middleware use https://github.com/pillarjs/send internally to stream file
So you can do this
app.use('/*', express.static('./src/client'));
It will, by default, set / to src/client/index.html, you can change that behaviour by setting index option as specified here https://github.com/expressjs/serve-static
If you want to redirect /* to ./src/client/index.html do this
// first set the static middleware
app.use('/public', express.static('./src/client'));
// then use redirect
app.get('/*', function(req, res, next){
res.redirect('/public/index.html');
});
This setup will redirect everything to public/index.html. If you want to add APIs or other routes, put it before the app.get('/*')