VirtualFS

This is a library that allows you to access various datastores in a unified way. Local FS and Github support in included, feel free to contibute other backends.

The API is designed to be compatible with the standard File and Dir APIs. Currently data access is read-only.

Installation

Add this line to your application's Gemfile:

gem 'virtualfs'

And then execute:

$ bundle

Or install it yourself as:

$ gem install virtualfs

Usage

Read a file for a local directory

fs = VirtualFS::Local.new :path => '/home/evol/hello'
file = fs["hello_world"].first  # fs[pattern] is an alias for fs.glob(pattern)

file.read

List the root directory of a Github repository

fs = VirtualFS::Github.new :user => 'evoL', :repo => 'virtualfs'
fs.entries

Find recursively files in subfolders

fs = VirtualFS::Github.new :user => 'evoL', :repo => 'virtualfs'
rb_files = fs.glob('**/*.rb')

Caching

cache = VirtualFS::FileCache.new :filename => 'file.cache', :expires_after => 3600
fs = VirtualFS::Github.new :user => 'evoL', :repo => 'virtualfs', :cache => cache

Available cache providers are RuntimeCache and FileCache.

The Anatomy of a Backend

A backend is a subclass of VirtualFS::Backend. It has to define the following methods:

#entries - lists the contents of a directory, like Dir.entries. Optionally accepts a path parameter, which specifies the path to the directory that will be listed. By default it lists the root directory of the backend.
#glob - lists files mathing the pattern, like Dir.glob. Optionally accepts a path parameter.
#stream_for - returns an IO object for the file specified by the path parameter.

The arrays returned by #entries and #glob are arrays of VirtualFS::Dir and VirtualFS::File objects, which mimic the API of the respective standard library classes. The VirtualFS::Backend class provides the #map_entries method for easy creation of those lists within backends.

Basic usage:

map_entries(paths) { |path| is_directory? path }

Instead of an array of strings you can supply an array of any objects, as long as they have a method for getting the path. The default method for getting the path of an object is #to_s.

map_entries(objects, :get_path) { |obj| obj.is_directory? }

Also, it is possible to cache the results of your code in the backend. It's simple:

cache { get_your_remote_data }

The remote data will then be cached using the user specified cache provider.

Contributing

Fork it
Create your feature branch (git checkout -b my-new-feature)
Commit your changes (git commit -am 'Added some feature')
Push to the branch (git push origin my-new-feature)
Create new Pull Request