gistfile1.rb

#!/usr/bin/env ruby
#
# Based on drbfs example by Kent Sibilev

require 'lib/fusefs'

# We're basically just passing all requests on to the local filesystem.
class UfsDirectory
  def initialize(dir)
    @dir = dir
    @files = {}
  end

  def contents(path)
    Dir[File.join(@dir, path,'*')].map{|fn| File.basename fn}
  end

  %w|file? directory? executable? size delete|.each do |name|
    define_method(name) do |path|
      File.send name, File.join(@dir, path)
    end
  end

  %w|mkdir rmdir|.each do |name|
    define_method(name) do |path|
      Dir.send name, File.join(@dir, path)
    end
  end

  %w|can_write? can_delete? can_mkdir? can_rmdir?|.each do |name|
    define_method(name) do |path|
      true
    end
  end

  def raw_rename(path,dest)
    puts "HOOK: renamed #{path} to #{dest}"
    File.rename(File.join(@dir,path),File.join(@dir,dest))
  end

  def raw_open(path, mode)
    return true if @files.has_key? path
    @files[path] = File.open(File.join(@dir, path), mode)
    return true
  rescue
    puts $!
    false
  end

  def raw_read(path, off, size)
    file = @files[path]
    return unless file
    file.seek(off, File::SEEK_SET)
    file.read(size)
  rescue
    puts $!
    nil
  end

  def raw_write(path, off, sz, buf)
    file = @files[path]
    return unless file
    file.seek(off, File::SEEK_SET)
    file.write(buf[0, sz])
  rescue
    puts $!
  end

  def raw_close(path)
    file = @files[path]
    return unless file
    file.close
    @files.delete path
  rescue
    puts $!
  end
end

if $0 == __FILE__
  #raw filesystem
  FuseFS.set_root(UfsDirectory.new("./photos"))
  #hooked filesystem
  FuseFS.mount_under("./virt_photos", "allow_root") 
  FuseFS.run
end