module Rack::Handler

Handlers connect web servers with Rack.

Rack includes Handlers for Thin, WEBrick, FastCGI, CGI, SCGI and LiteSpeed.

Handlers usually are activated by calling MyHandler.run(myapp). A second optional hash can be passed to include server-specific configuration.

Public Class Methods

default ()

# File lib/rack/handler.rb, line 51
def self.default
  # Guess.
  if ENV.include?("PHP_FCGI_CHILDREN")
    Rack::Handler::FastCGI
  elsif ENV.include?(REQUEST_METHOD)
    Rack::Handler::CGI
  elsif ENV.include?("RACK_HANDLER")
    self.get(ENV["RACK_HANDLER"])
  else
    pick SERVER_NAMES
  end
end

get (server)

# File lib/rack/handler.rb, line 13
def self.get(server)
  return unless server
  server = server.to_s

  unless @handlers.include? server
    load_error = try_require('rack/handler', server)
  end

  if klass = @handlers[server]
    const_get(klass)
  else
    const_get(server, false)
  end

rescue NameError => name_error
  raise load_error || name_error
end

pick (server_names)

Select first available Rack handler given an ‘Array` of server names. Raises `LoadError` if no handler was found.

> pick ['thin', 'webrick']
=> Rack::Handler::WEBrick

# File lib/rack/handler.rb, line 36
def self.pick(server_names)
  server_names = Array(server_names)
  server_names.each do |server_name|
    begin
      return get(server_name.to_s)
    rescue LoadError, NameError
    end
  end

  raise LoadError, "Couldn't find handler for: #{server_names.join(', ')}."
end

# File lib/rack/handler.rb, line 85
def self.register(server, klass)
  @handlers ||= {}
  @handlers[server.to_s] = klass.to_s
end

try_require (prefix, const_name)

Transforms server-name constants to their canonical form as filenames, then tries to require them but silences the LoadError if not found

Naming convention:

Foo # => 'foo'
FooBar # => 'foo_bar.rb'
FooBAR # => 'foobar.rb'
FOObar # => 'foobar.rb'
FOOBAR # => 'foobar.rb'
FooBarBaz # => 'foo_bar_baz.rb'

# File lib/rack/handler.rb, line 75
def self.try_require(prefix, const_name)
  file = const_name.gsub(/^[A-Z]+/) { |pre| pre.downcase }.
    gsub(/[A-Z]+[^A-Z]/, '_\&').downcase

  require(::File.join(prefix, file))
  nil
rescue LoadError => error
  error
end