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,
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
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');
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');
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 question is over 5 years old but every answer has some problems.
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
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, preformant 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.
Every example serves files from the public
directory and supports the minumum functionality of:
index.html
as a default directory indexI 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/');
});
I posted all of the examples on GitHub with more explanation.
Examples with express.static
, express
, connect
, http
and net
:
Other project using only express.static
:
Test results are available on Travis:
Everything is tested on Node versions 4, 5, 6, and 7.
Other related answers:
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.
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.