CDNMD5

A helful library to allow you to create a unique version of every asset on a CDN, but renaming the filename (on the CDN) to the md5sum hash of the file.

This means you always defeate browser cache when the file is changed, but also always utilize browser cache when the file remains unchanged...

No more query string timestamps.

Justification

File Assets need to be stored on a CDN but each "specific" version of the files need to be accessed, and sometimes we are going forward in time, and backward in time, all versions need to be available, uniquely

As such, the basic plan is:

on file creation/editing: before you use this library, create the file... then use this library to:

make a md5sum of the file ($md5hash)
store the md5sum of the file in a config file (commited to git)
make a copy of the file renamed to "{$filename}_{$md5hash}.{$ext}"
transfer the renamed copy to the CDN

At the time of rendering the file:

Cdnmd5::url($filename) ==> http://domain/filename_md5hash.ext

This function looks up the md5hash stored in the config file and returns the URL to the CDN for the file...

If we are in development mode: Configure::read('Cdnmd5.disabled') == true

If that md5hash doesn't exist for some reason (or is empty) we try to just load the "real" file from the local repository.

Limitations:

Filenames must be unique, all path data is stripped when determining the md5hash for a file and when transfering files to the CDN. This means if you have 'webroot/css/main.css' and 'webroot/plugin/main.css' that they will walk on top of each other and you'll never get what you want.

I highly recommend you aggregate your assets into one or two files per type, before you consider the cdnmd5 processing.

Suggestions

https://github.com/markstory/asset_compress (cakephp toolkit for all assets)
https://developers.google.com/closure/ (slow, java, but best compression and good parser warnings)
https://github.com/mishoo/UglifyJS2 (fast JS aggregation/minification)

Note: This library only works with one CDN at a time (for now).

Requirements:

php5
php5-curl
CakePHP (could be decoupled with a little bit of work)

(CakePHP 1.3, CakePHP 2x versions available, switch branches)

NOTE: submodules added for API Libs, inside plugin/vendors

git://github.com/zeroasterisk/php-opencloud.git -> [plugindir]/vendors/php-opencloud

Installation:

Put the plugin into the correct place in the CakePHP app:

CakePHP 1.3

cd repo
git submodule add git://github.com/zeroasterisk/cdnmd5 app/plugins/cdnmd5
cd app/plugins/cdnmd5
git checkout 1.3
cd ../../..
git submodule update --init --recursive
cp app/plugins/cdnmd5/config/cdnmd5.example.php app/config/cdnmd5.php
vim app/config/cdnmd5.php

Usage:

After you create your CDNable assets (AssetCompress, Closure, Uglify, CssMin, etc)

App::Import('Lib', 'Cdnmd5.Cdnmd5');
Cdnmd5::process(APP . $fullPathToFile);

And how to render it in your Views

App::Import('Lib', 'Cdnmd5.Cdnmd5');
$this->Html->script(Cdnmd5::url($webrootRelativePathTofile));

Or with the simple helper:

$this->Cdnmd5->script($webrootRelativePathTofile);

About / License

Author: Alan Blount alan@zeroasterisk.com

License: MIT (see https://github.com/zeroasterisk/cdnmd5/LICENSE.txt)

(pull requests encouraged)

zeroasterisk / cdnmd5