# frozen_string_literal: true
# Released under the MIT License.
# Copyright, 2022-2023, by Samuel Williams.
module Rackup
# *Handlers* connect web servers with Rack.
#
# Rackup includes Handlers for WEBrick and CGI.
#
# Handlers usually are activated by calling <tt>MyHandler.run(myapp)</tt>.
# A second optional hash can be passed to include server-specific
# configuration.
module Handler
@handlers = {}
# Register a named handler class.
def self.register(name, klass)
if klass.is_a?(String)
warn "Calling Rackup::Handler.register with a string is deprecated, use the class/module itself.", uplevel: 1
klass = self.const_get(klass, false)
end
name = name.to_sym
@handlers[name] = klass
end
def self.[](name)
name = name.to_sym
begin
@handlers[name] || self.const_get(name, false)
rescue NameError
# Ignore.
end
end
def self.get(name)
return nil unless name
name = name.to_sym
if server = self[name]
return server
end
begin
require_handler("rackup/handler", name)
rescue LoadError
require_handler("rack/handler", name)
end
return self[name]
end
RACK_HANDLER = 'RACK_HANDLER'
RACKUP_HANDLER = 'RACKUP_HANDLER'
SERVER_NAMES = %i(puma falcon webrick).freeze
private_constant :SERVER_NAMES
# Select first available Rack handler given an `Array` of server names.
# Raises `LoadError` if no handler was found.
#
# > pick ['puma', 'webrick']
# => Rackup::Handler::WEBrick
def self.pick(server_names)
server_names = Array(server_names)
server_names.each do |server_name|
begin
server = self.get(server_name)
return server if server
rescue LoadError
# Ignore.
end
end
raise LoadError, "Couldn't find handler for: #{server_names.join(', ')}."
end
def self.default
if rack_handler = ENV[RACKUP_HANDLER]
self.get(rack_handler)
elsif rack_handler = ENV[RACK_HANDLER]
warn "RACK_HANDLER is deprecated, use RACKUP_HANDLER."
self.get(rack_handler)
else
pick SERVER_NAMES
end
end
# 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'
def self.require_handler(prefix, const_name)
file = const_name.to_s.gsub(/^[A-Z]+/) { |pre| pre.downcase }.
gsub(/[A-Z]+[^A-Z]/, '_\&').downcase
require(::File.join(prefix, file))
end
end
end
|