A simple file server and uploader using sinatra

bfile.rb

#!/usr/bin/env ruby

require 'rubygems'
require 'sinatra'
require 'haml'

$pwd = ENV['PWD']

if File.exists?(ARGV.last)
  if ARGV.last != 'bfile.rb'
    $download_file = ARGV.last
  end
end

def file_listing(directory)
  Dir.glob(directory + '/*')
end

get '/upload' do
  haml :upload
end

post '/upload' do 
  file = params[:file]
  filename = file[:filename]
  tempfile = file[:tempfile]
  File.open(filename, 'w') {|f| f.write tempfile.read}
  redirect '/browse'
end

get '/download/:filename' do |filename|
  file = File.join($pwd, filename)
  send_file(file, :disposition => 'inline')
end

get '/browse' do
  @files = file_listing($pwd)
  haml :index
end

get '/bfile.rb' do
  file = File.join($pwd, 'bfile.rb')
  send_file(file, :disposition => 'attachment')
end

get '/' do
  if $download_file
    file = File.join($pwd, $download_file)
    send_file(file, :disposition => 'attachment')
  else
    redirect '/browse'
  end
end

__END__

@@ layout
%html
  %a{:href => '/browse'}Browse Files
  %a{:href => '/upload'}Upload a File
  = yield
  

@@ index
%h1 File Server
%table
  %tr
    %th File
    %th Size
  - for file in @files
    - if File.file?(file)
      %tr
        %td
          %a{:title => file, :href => '/download/' + File.basename(file)}=File.basename(file)
        %td= File.size(file).to_s + "b"

@@upload
%h1 Upload

%form{:action=>"/upload",:method=>'post',:enctype=>"multipart/form-data"}
  %input{:type => "file",:name => "file"}
  %input{:type => "submit",:value => "Upload"}