cdnizer

A module for replacing local links with CDN links, includes fallbacks and customization.

cdnizer

This library will replace local file references in HTML and other files with CDN locations. This allows you to work with local copies of libraries during development, and then automate switching to your CDN version when you deploy your application.

For example, if you have a development file that looks like this:

<html>
<head>
<script type="text/javascript" src="bower_components/angular/angular.js"></script>

You can use cdnizer to automatically convert it to this during your build process (every change here can be customized):

<html>
<head>
<script>
function cdnizerLoad(u) {
    document.write('<scr'+'ipt src="'+encodeURIComponent(u)+'"></scr'+'ipt>';
}
</script>
<script type="text/javascript" src="//ajax.googleapis.com/ajax/libs/angularjs/1.2.10/angular.min.js"></script>
<script>if(!(angular)) cdnizerLoad("bower_components/angular/angular.js");</script>

If you want to use this library during a gulp build, gulp-cdnizer has you covered.

  • It's flexible without being overly complicated.
  • Handles private and multiple public CDNs in the same build.
  • It can use your Bower installation to determine the correct file versions—no more getting "upgraded" during your build.
  • Provides optional fallback scripts for failed file loading. (By default it can only handle failed JavaScript files, but it's easy to provide a custom solution.)

cdnizer now can load CDN data from existing *-cdn-data packages, currently google-cdn-data, cdnjs-cdn-data, and jsdelivr-cdn-data. Now you can configure common public CDNs with a single line!

The version field has been changed in this release. Previously, it was the exact version as it existing within Bower. Now, version is the string major(.minor)?(.patch)?, with any trailing (-beta*, -snapshot*, etc) information removed. (Alpha-numeric characters that are attached to the version string, as in 1.0.0rc1, are not stripped.)

You can still access the full version string via versionFull, which is not modified at all.

First, install cdnizer:

npm install --save cdnizer

Then, use it like so:

var cdnizerFactory = require("cdnizer"),
    cdnizer = cdnizerFactory({
        defaultCDNBase: "//my.cdn.host/base",
        allowRev: true,
        allowMin: true,
        files: [
          
            // This file is on the default CDN, and will replaced with //my.cdn.host/base/js/app.js 
            'js/app.js',
            
            // On Google's public CDN 
            {
                file: 'vendor/angular/angular.js',
                package: 'angular',
                test: 'window.angular',
                cdn: '//ajax.googleapis.com/ajax/libs/angularjs/${ version }/angular.min.js'
            },
            
            // On Firebase's public CDN 
            {
                file: 'vendor/firebase/firebase.js',
                test: 'window.Firebase',
                cdn: '//cdn.firebase.com/v0/firebase.js'
            }
        ]
    });
              
// Load the file 
var contents = fs.readFileSync('./src/index.html', 'utf8');
          
// Replace the file's contents 
contents = cdnizer(contents);

Alternatively, you can just pass in the files array if you don't need to provide any options, and only have custom files:

var cdnizerFactory = require("cdnizer"),
    cdnizer = cdnizerFactory([
        {
            file: 'vendor/angular/angular.js',
            package: 'angular',
            test: 'window.angular',
            // use alternate providers easily 
            cdn: '//cdnjs.cloudflare.com/ajax/libs/angularjs/${ version }/angular.min.js'
        },
        {
            file: 'vendor/firebase/firebase.js',
            test: 'window.Firebase',
            cdn: '//cdn.firebase.com/v0/firebase.js'
        }
    ]);

You can also use globs to define groups of file, and dynamic filename properties:

var cdnizerFactory = require("cdnizer"),
    cdnizer = cdnizerFactory([{
        file: 'vendor/angular/*.js',
        package: 'angular',
        test: 'window.angular',
        cdn: '//ajax.googleapis.com/ajax/libs/angularjs/${ version }/${ filenameMin }'
    }]);

Works great on url()s in CSS files, too:

var cdnizerFactory = require("cdnizer"),
    cdnizer = cdnizerFactory({
        defaultCDNBase: '//my.cdn.url/',
        relativeRoot: 'css',
        files: ['**/*.{gif,png,jpg,jpeg}']
    });
 
var cssFile = fs.readFileSync('./css/style.css', 'utf8');
cssFile = cdnizer(cssFile);

New in v1.0, you can use simplified strings for common public CDNs, like so:

var cdnizerFactory = require("cdnizer"),
    cdnizer = cdnizerFactory([
        'google:angular',          // for most libraries, that's all you'll need to do! 
        'cdnjs:jquery',
        {
            cdn: 'jsdelivr:yui',   // You can also use a known CDN, while… 
            package: 'yui3',       // overriding the package name for Bower, and… 
            test: 'window.YUI'     // providing a custom fallback test 
        },
        // you can also specify alternate files within a package: 
        'jsdelivr:yui:anim-base/anim-base-min.js@3.17.2'
    ]);

Need multiple files from the one package on a common CDN? Here's two solutions:

// Manually list every file… 
var cdnizerFactory = require("cdnizer"),
    cdnizer = cdnizerFactory([
        'cdnjs:angular.js:angular.min.js',
        'cdnjs:angular.js:angular-touch.min.js',
        'cdnjs:angular.js:i18n/angular-locale_fr-fr.js'
    ]);
 
// Or wire up a pattern: 
var cdnizerFactory = require("cdnizer"),
    cdnizer = cdnizerFactory([
        // matches all root angular files 
        {
            file: '**/angular/*.js',
            cdn: 'cdnjs:angular.js:${ filenameMin }' // Yes, you can apply patterns to the filename! 
        },
        // matches all i18n angular files 
        {
            file: '**/angular/i18n/*.js',
            cdn: 'cdnjs:angular.js:i18n/${ filename }' // These i18n files are not minified 
        }
    ]);

Creates a new cdnizer function that can be used to process file contents. You can either pass in a configuration object, or you can pass in an array of files if you don't need to change the default shared options.

See Usage above for examples.

Type: String
Default: '' (disabled)

Used for a default, custom CDN, usually for your own files. This will be used in the defaultCDN property to define the default path for a CDN unless overridden.

Type: String
Default: '${ defaultCDNBase }/${ filepathRel }'

This is the default pattern used for generating CDN links when one isn't provided by a specific file.

Type: String
Default: ''

If you are processing a file that references relative files, or is not rooted to the CDN, you must set relativeRoot to get correct results. This relative path will be appended to the file path and the path resolved to remove relative URLs.

For example, if you have a CSS file at style/main.css, and you reference images as ../img/foo.png, you should set relativeRoot to 'style/'. Now if your defaultCDNBase is //example/, the image will be resolved to //example/img/foo.png.

If you do not set relativeRoot when referencing relative files, your files will not match, and they will not be replaced with CDN URLs.

Type: Boolean
Default: true

Allow for file names with gulp-rev appended strings, in the form of <file>-XXXXXXXX.<ext>. If you are using the gulp-rev plugin, this will automatically match filenames that have a rev string appeneded to them. If you are not using gulp-rev, then you can disable this by setting allowRev to false, which will prevent possible errors in accidentally matching similar file names.

You can always manually configure your globs to include an optional rev string by using the form ?(<rev glob here>), such as name?(-????????).ext for appended revs.

Type: Boolean
Default: true

Allow for file names that optionally have .min inserted before the file extension (but after rev, if enabled). This allows you to use the base name for a file, and have cndizer match the minified name.

Type: String
Default:

<script>
function cdnizerLoad(u) {
    document.write('<scr'+'ipt src="'+encodeURIComponent(u)+'"></scr'+'ipt>';
}
</script> 

Overwrite the default fallback script. If any of the inputs has a fallback, this script is injected before the first occurrence of <link, <script, or </head> in the HTML page. Ignored for files that don't contain <head.

If you already have a script loader (such as yepnope or Modernizr), you can set this to an empty string and override the fallbackTest below to use that instead. Of course, this won't help if you are loading those scripts off a CDN and they fail!

Type: String
Default: '<script>if(!(${ test })) cdnizerLoad("${ filepath }");</script>'

Overwrite the default fallback test. Note that all options availble to options.files[].cdn below are available to this template as well, along with the options.files[].test string.

Type: String
Default: null

If provided, this is the directory to look for Bower components in. If not provided, cdnizer will attempt to look for the .bowerrc file, and if that is not found or does not specify a directory, it falls back to './bower_components'.

Once the directory is determined, the script will look for files in <bowerComponents>/bower.json or <bowerComponents>/.bower.json to try to determine the version of the installed component.

Type: Array
Default: []

Array of custom matchers. Use this to add extra patterns within which you would like to cdn-ize URLs, for example if you have such URLs in data-attributes. The matchers should include regular expressions with three matching groups:

  1. Leading characters
  2. The actual URL to work on, and
  3. Trailing characters, which should include the end tag if you want a fallback script injected.

Example (matches the data-src attribute in <img> tags):

matchers: [
    {
        pattern: /(<img\s.*?data-src=["'])(.+?)(["'].*?>)/gi,
        //groups: (       leading        )(url)(trailing) 
        fallback: false
    }
]

You can also specify just a regular expression. In that case, fallback will default to false.

Equivalent example:

matchers: [
    /(<img\s.*?data-src=["'])(.+?)(["'].*?>)/gi
]

Type: Array Default: []

Future-proof option to add additional *-cdn-data packages. These packages must be in the same format as google-cdn-data. The format is to only include the leading part of the package name, for example, cdnjs-cdn-data would be included as simply 'cdnjs'.

Type: Array
Default: (none) required

Array of sources or objects defining sources to cdnize. Each item in the array can be one of three types, a simple glob, a public CDN string, or object hashmap.

When using a glob, if it matches a source, the defaultCDN template is applied. Because there is no test, the script will not have a fallback.

Examples:

'**/*.js' // matches any .js file anywhere 
'js/**/*.js' // matches any *.js file under the js folder 
'styles/main.css' // only matches styles/main.css, possibly rev'd or min'd based on options 
'img/icon/foo??.{png,gif,jpg}' // img/icon/foo10.png, img/icon/fooAA.gif, etc 

Public CDN strings make it easy to add known libraries from common public CDN repositories. They always take the form of '<provider>:<package>(:filename)?(@version)?'. Currently, cdnizer has built-in support for Google, cdnjs, and jsDelivr, via the existing packages maintained by Shahar Talmi.

Examples:

'google:jquery'                             // Note that it's all lowercase 
'google:jquery@1.0.0'                       // provide a version if you are not using Bower OR to override it 
'google:angular'
// this loads the angular-touch file from angular on cdnjs 
'cdnjs:angular.js:angular-touch.min.js'     // you need `.js` for angular on cdnjs, but not on Google! 
'jsdelivr:angularjs'                        // jsdelivr has it different still 

The result of these patterns follows the following process:

  1. Look up the package (e.g.: angular) within the correct CDN's cdn-data.
  2. Get the URL for the package with the version set to ${ version }, which allows dynamic replacement of the version later
  3. If we are provided an alternate filename, replace everything in the URL after ${ version }/ with the new filename. This is how you can select alternate files on the CDN.
  4. Set the cdn property to the URL.
  5. Grab everything after ${ version }/—this is assumed to be the filename—and set the file property (i.e.: the glob pattern) to **/«filename».
  6. Set the package property either to a known package (some known packages are mapped to their Bower package name) or to the passed-in package name.
  7. If we know the correct fallback test for a package, use that. Otherwise, don't set a test.
  8. If a version was passed in, store that as well under the version property.

You can also use a common cdn while customizing the result by using a common CDN with the cdn option within a hashmap. You will need to do this if the CDN provider uses a different package name than Bower, or if you want to provide a fallback test (excluding a few popular libraries).

Note: you can use template strings in the :filename portion of the string. However, if you do this, you'll need to overwrite the file property by using a hashmap (below), or it will try to match the literal string. For example, you can this will match any file directly under an angular directory, and replace it with the CDN equivalent:

{
    file: '**/angular/*.js',
    cdn: 'cdnjs:angular.js:${ filenameMin }'
}

If this solution gets a little too "magic-y", you can always just revert to manually specifying the hashmap, which might be easier. The hashmap alternative looks like this:

{
    file: '**/angular/*.js',
    package: 'angular',
    test: 'window.angular',
    cdn: '//cdnjs.cloudflare.com/ajax/libs/angular.js/${ version }/${ filenameMin }'
}

Important Notes:

  1. Case matters with these strings. Make sure you are not capitalizing the packages (such as jQuery, instead of jquery), or the output will be incorrect.

  2. The packages may have different names on different public CDNs. Make sure you look up the package name on the CDN website first. For example, AngularJS is angular on Google, angular.js on cdnjs, and angularjs on jsDelivr!

  3. You must provide the version if you are not using Bower to manage your packages, or if you want to override the Bower version (not recommended).

  4. Due to the way versions are calculated, -beta*, -unstable*, and -snapshot* releases will not work with common CDNs. This means only projects with standard 1-, 2-, or 3-part version strings will work.

  5. The CDN packages available are limited to those included in the cdn-data packages, which means they might not always be up-to-date with the latest public packages. However, the version information is not used at all by cdnizer, which means you can update to the latest version faster.

The object hashmap gives you full control, using the following properties:

Type: String
Default: (none) required

Glob to match against for the file to cdnize. All properties within this object will be applied to all files that match the glob. Globs are matched in a first-come, first-served basis, where only the first matched object hashmap is applied.

Type: String
Default: (none)

Bower package name for this source or set of sources. By providing the package name, cdnizer will look up the version string of the currently installed Bower package, and provide it as a property to the cdn string. This is done by looking for either the bower.json or .bower.json file within your Bower components directory.

The benefit of doing it this way is that the version used from the CDN always matches your local copy. It will never automatically be updated to a newer patch version without being tested.

Type: String
Default: options.defaultCDN

This it the template for the replacement string. It can either be a custom CDN string, or it can be a common public CDN string, using the same format as a public CDN string above.

Common Public CDN String:

Load in the default data for an existing common public CDN, using the format '<provider>:<package>(:filename)?(@version)?'. You can then customize the settings for the package, by overriding any property in this section (e.g.: providing a fallback test, a different package name, or even matching a different file).

Custom CDN String:

Provide a custom CDN string, which can be a simple static string, or contain one or more underscore/lodash template properties to be injected into the string:

  • versionFull: if package was provided, this is the complete version currently installed version from Bower.
  • version: if package was provided, this is the major(.minor)?(.patch)? version number, minus any trailing information (such as -beta* or -snapshot*).
  • major: if package was provided, this is the major version number.
  • minor: if package was provided, this is the minor version number.
  • patch: if package was provided, this is the patch version number.
  • defaultBase: the default base provided above. Note that this will never end with a trailing slash.
  • filepath: the full path of the source, as it exists currently. There is no guarantee about the whether this contains a leading slash or not, so be careful.
  • filepathRel: the relative path of the source, guaranteed to never have a leading slash. The path is also processed against options.relativeRoot above, to try and remove any parent directory path elements.
  • filename: the name of the file, without any parent directories
  • filenameMin: the name of the file, without any rev tags (if allowRev is true), but with a .min extension added. This won't add a min if there is one already.
  • package: the Bower package name, as provided above.

Type: String
Default: (none)

If provided, this string will be evaluated within a javascript block. If the result is truthy, then we assume the CDN resource loaded properly. If it isn't, then the original local file will be loaded. This is ignored for files that don't get the fallback script.

This snippet will be inserted exactly as provided. If the package fails to load from the CDN, the global variable won't exist, so you need to check for it's existence on an existing global object. Usually this will be window, which you'll see through most of the examples here.

When using a common public CDN, some popular packages come with fallback tests. The current packages that have a built-in fallback test are:

  • AngularJS
  • Backbone.js
  • Dojo
  • EmberJS
  • jQuery
  • jQuery UI
  • Lo-Dash
  • MooTools
  • Prototype
  • React
  • SwfObject
  • Underscore

For any other packages, you'll need to provide the fallback test yourself.

See options.fallbackScript and options.fallbackTest for more information.

If you'd like to support this and other OverZealous Creations (Phil DeJarnett) projects, donate via Gratipay!

You can learn a little more about me and some of the work I do for open source projects in an article at CDNify.

MIT License