Built-in optimization of images in production mode using OptiPNG and JPEGTran.
Supports Sass, LESS, and Stylus using respective stylesheet compilers.
JavaScript assets are mangled and minified using UglifyJS.
Automatic detection of asset changes and will only upload changed assets to S3 in production mode.
Utilizes cachebusting, which is inspired by express-cachebuster and h5bp.
All assets are compressed using zlib into a gzip buffer for S3 uploading with Content-Encoding header set to gzip.
Embed multiple assets as a single <script> or <link> tag using the built-in dynamic view helper.
Loads and processes assets per view (allowing you to minimize client HTTP requests).
Combine commonly used assets together using a simple array argument.
Uploads changed assets automatically and asynchronously to Amazon S3 (only in production mode) using knox.

## Add-on Modules (coming soon)

express-cdn-cloudfront - Amazon S3 and Amazon CloudFront
express-cdn-maxcdn - MaxCDN and Amazon S3
express-cdn-cloudfiles - Rackspace CloudFiles
express-cdn-cloudflare - CloudFlare and Amazon S3

## Lazy Web Requests

Automatic parsing of CDN(...) in stylesheets and scripts.

// Here is a LESS mixin which could then get parsed in CSS for /CDN/ and uploaded to storage/CDN
.CDN (@image: '/path/to/cdn.png') {
  background-image: url("@{image}?mixin=CDN");
}

Add options to pick CDN network (e.g. MaxCDN vs. Amazon vs. Rackspace)
Add tests for all asset types.
Modularization of /lib/main.js please!
Support Express 3.x.x+ and utilize async with view helper.
Convert from fs.statSync to fs.stat with callback for image assets modified timestamp hack.
Investigate why Chrome Tools Audit returns leverage proxy cookieless jargon.

## How does it work?

When the server is first started, the module returns a view helper depending on the server environment (production or development). It also recursively searches through your viewsDir for any views containing instances of the CDN(...) view helper. After parsing each instance and removing duplicates, it will use your S3 credentials to upload a new copy of the production-quality assets. Enjoy :).

## Environment Differences

Development Mode:

Assets are untouched, cachebusted, and delivered as typical local files for rapid development.

Production Mode:

Assets are optimized, minified, mangled, gzipped, delivered by Amazon CloudFront CDN, and hosted from Amazon S3.

## CDN Setup Instructions

Visit https://console.aws.amazon.com/s3/home and click Create Bucket.

Bucket Name: bucket-name
Region: US Standard

Upload index.html to your new bucket (this will serve as a placeholder in case someone accesses http://cdn.your-site.com/).
Select index.html in the Objects and Folders view from your S3 console and click Actions → Make Public.
Visit https://console.aws.amazon.com/cloudfront/home and click Create Distribution.

Choose an origin:
- Origin Domain Name: bucket-name.s3.amazonaws.com
- Origin ID: S3-bucket-name
Create default behavior:
- Path Pattern: Default (*)
- Origin: S3-bucket-name
- Viewer Protocol Policy: HTTP and HTTPS
- Object Caching: Use Origin Cache Headers
- Forward Query String: No (Improves Caching)
Distribution details:
- Alternate Domain Names (CNAMEs): cdn.your-domain.com
- Default Root Object: index.html
- Logging: Off
- Comments: Created with express-cdn by @niftylettuce.
- Distribution State: Enabled

Copy the generated Domain Name (e.g. xyz.cloudfront.net) to your clipboard.
Log in to your-domain.com's DNS manager, add a new CNAME "hostname" of cdn, and paste the contents of your clipboard as the the "alias" or "points to" value.
After the DNS change propagates, you can test your new CDN by visiting http://cdn.your-domain.com (the index.html file should get displayed).

## Installation

### Install Dependencies

Linux

# install optipng and jpegtran packages
sudo apt-get install optipng libjpeg-progs

OS X (with Homebrew)

# install optipng and jpegtran packages
brew install optipng libjpeg

Install express-cdn module

npm install express-cdn

## Usage

Server

// # express-cdn

var express = require('express')
  , path    = require('path')
  , app     = express.createServer()
  , semver  = require('semver');

// Set the CDN options
var options = {
    publicDir  : path.join(__dirname, 'public')
  , viewsDir   : path.join(__dirname, 'views')
  , domain     : 'cdn.your-domain.com'
  , bucket     : 'bucket-name'
  , key        : 'amazon-s3-key'
  , secret     : 'amazon-s3-secret'
  , hostname   : 'localhost'
  , port       : 1337
  , ssl        : false
  , production : true
};

// Initialize the CDN magic
var CDN = require('express-cdn')(app, options);

app.configure(function() {
  app.set('view engine', 'jade');
  app.set('view options', { layout: false, pretty: true });
  app.enable('view cache');
  app.use(express.bodyParser());
  app.use(express.static(path.join(__dirname, 'public')));
});

// Add the view helper
if (semver.lt(express.version, '3.0.0')) {
  app.locals({ CDN: CDN() });
} else {
  app.dynamicHelpers({ CDN: CDN });
}

app.get('/', function(req, res, next) {
  res.render('basic');
  return;
});

console.log("Server started: http://localhost:1337");
app.listen(1337);

View Engine

Jade

// #1 - Load an image
!= CDN('/img/sprite.png')

// #2 - Load an image with a custom tag attribute
!= CDN('/img/sprite.png', { alt: 'Sprite' })

// #3 - Load a script
!= CDN('/js/script.js')

// #4 - Load a script with a custom tag attribute
!= CDN('/js/script.js', { 'data-message': 'Hello' })

// #5 - Load and concat two scripts
!= CDN([ '/js/plugins.js', '/js/script.js' ])

// #6 - Load and concat two scripts with custom tag attributes
!= CDN([ '/js/plugins.js', '/js/script.js' ], { 'data-message': 'Hello' })

// #7 - Load a stylesheet
!= CDN('/css/style.css')

// #8 - Load and concat two stylesheets
!= CDN([ '/css/style.css', '/css/extra.css' ])

EJS

<!-- #1 - Load an image -->
<%- CDN('/img/sprite.png') %>

<!-- #2 - Load an image with a custom tag attribute -->
<%- CDN('/img/sprite.png', { alt: 'Sprite' }) %>

<!-- #3 - Load a script -->
<%- CDN('/js/script.js') %>

<!-- #4 - Load a script with a custom tag attribute -->
<%- CDN('/js/script.js', { 'data-message': 'Hello' }) %>

<!-- #5 - Load and concat two scripts -->
<%- CDN([ '/js/plugins.js', '/js/script.js' ]) %>

<!-- #6 - Load and concat two scripts with custom tag attributes -->
<%- CDN([ '/js/plugins.js', '/js/script.js' ], { 'data-message': 'Hello' }) %>

<!-- #7 - Load a stylesheet -->
<%- CDN('/css/style.css') %>

<!-- #8 - Load and concat two stylesheets -->
<%- CDN([ '/css/style.css', '/css/extra.css' ]) %>

Automatically Rendered HTML

Development Mode

<!-- #1 - Load an image -->
<img src="/img/sprite.png?v=1341214029" />

<!-- #2 - Load an image with a custom tag attribute -->
<img src="/img/sprite.png?v=1341214029" alt="Sprite" />

<!-- #3 - Load a script -->
<script src="/js/script.js?v=1341214029" type="text/javascript"></script>

<!-- #4 - Load a script with a custom tag attribute -->
<script src="/js/script.js?v=1341214029" type="text/javascript" data-message="Hello"></script>

<!-- #5 - Load and concat two scripts -->
<script src="/js/plugins.js?v=1341214029" type="text/javascript"></script>
<script src="/js/script.js?v=1341214029" type="text/javascript"></script>

<!-- #6 - Load and concat two scripts with custom tag attributes -->
<script src="/js/plugins.js?v=1341214029" type="text/javascript" data-message="Hello"></script>
<script src="/js/script.js?v=1341214029" type="text/javascript" data-message="Hello"></script>

<!-- #7 - Load a stylesheet -->
<link href="/css/style.css?v=1341214029" rel="stylesheet" type="text/css" />

<!-- #8 - Load and concat two stylesheets -->
<link href="/css/style.css?v=1341214029" rel="stylesheet" type="text/css" />
<link href="/css/extra.css?v=1341214029" rel="stylesheet" type="text/css" />

Production Mode

The protocol will automatically change to "https" or "http" depending on the SSL option.

The module will automatically upload and detect new/modified assets based off timestamp, as it utilizes the timestamp for version control! There is built-in magic to detect if individual assets were changed when concatenating multiple assets together (it adds the timestamps together and checks if the combined asset timestamp on S3 exists!).

<!-- #1 - Load an image -->
<img src="https://cdn.your-site.com/img/sprite.1341382571.png" />

<!-- #2 - Load an image with a custom tag attribute -->
<img src="https://cdn.your-site.com/img/sprite.1341382571.png" alt="Sprite" />

<!-- #3 - Load a script -->
<script src="https://cdn.your-site.com/js/script.1341382571.js" type="text/javascript"></script>

<!-- #4 - Load a script with a custom tag attribute -->
<script src="https://cdn.your-site.com/js/script.1341382571.js" type="text/javascript" data-message="Hello"></script>

<!-- #5 - Load and concat two scripts -->
<script src="https://cdn.your-site.com/plugins%2Bscript.1341382571.js" type="text/javascript"></script>

<!-- #6 - Load and concat two scripts with custom tag attributes -->
<script src="https://cdn.your-site.com/plugins%2Bscript.1341382571.js" type="text/javascript" data-message="Hello"></script>

<!-- #7 - Load a stylesheet -->
<link href="https://cdn.your-site.com/css/style.1341382571.css" rel="stylesheet" type="text/css" />

<!-- #8 - Load and concat two stylesheets -->
<link href="https://cdn.your-site.com/style%2Bextra.1341382571.css" rel="stylesheet" type="text/css" />

## Optional Features ### Using a custom logger

By default log messages will be sent to the console. If you would like to use a custom logger function you may pass it in as options.logger

The example below uses the Winston logging library.

var winston = require('winston');
winston.add(winston.transports.File, {filename: 'somefile.log'});

// Set the CDN options
var options = {
    publicDir  : path.join(__dirname, 'public')
  , viewsDir   : path.join(__dirname, 'views')
  , domain     : 'cdn.your-domain.com'
  , bucket     : 'bucket-name'
  , key        : 'amazon-s3-key'
  , secret     : 'amazon-s3-secret'
  , hostname   : 'localhost'
  , port       : 1337
  , ssl        : false
  , production : true
  , logger     : winston.info
};

// Initialize the CDN magic
var CDN = require('express-cdn')(app, options);

app.configure(function() {
  app.set('view engine', 'jade');
  app.set('view options', { layout: false, pretty: true });
  app.enable('view cache');
  app.use(express.bodyParser());
  app.use(express.static(path.join(__dirname, 'public')));
});

// Add the dynamic view helper
app.dynamicHelpers({ CDN: CDN });

Any output from express-cdn is now passed to winston.info() which writes to both console and somefile.log.

## Contributors

## License

MIT Licensed

Keywords

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Package last updated on 23 Aug 2012

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