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I’ve just released my first ever RubyGem. It’s a simple gem named Manifesto that dynamically generates an HTML 5 cache manifest for offline application caching. I got the idea whilst developing my Truth Tables Sinatra micro web application. It returns a list of files within the specified directory and sub-directories. By default it also includes a computed hash of the files' contents, so that if a file is changed a different hash is produced, causing the cache to be automatically invalidated.

Installation

To install the gem, use:

    [sudo] gem install manifesto
    

Usage

    # Basic usage, list all non-hidden files in ./public and include
    # a computed hash of their contents
    Manifesto.cache
    
    # Specify a directory
    Manifesto.cache :directory => './mobile'
    
    # Specify a directory and don't compute the hash
    Manifesto.cache :directory => './mobile', :compute_hash => false
    

Sample Output

    CACHE MANIFEST
    # Generated by manifesto (http://github.com/johntopley/manifesto)
    # Hash: 7013a3b8292ceeeb6336849bee1d1365
    /apple-touch-icon.png
    /apple-touch-startup.png
    /index.html
    /mobile/mobile.css
    /mobile/mobile.js
    

Sinatra Example

    require 'manifesto.rb'
    
    get '/manifest' do
      # Must be served with this MIME type
      headers 'Content-Type' => 'text/cache-manifest' 
      Manifesto.cache
    end
    

Ruby on Rails Example

    # Create a Rails 2.x route for the manifest
    map.manifest '/manifest', :controller => 'manifest', :action => 'show'
    
    # ...or a Rails 3.x route
    match '/manifest' => 'manifest#show'
    
    # Create a controller action
    def show
      headers['Content-Type'] = 'text/cache-manifest'
      render :text => Manifesto.cache, :layout => false
    end
    

Enjoy!