Compatibility with rackup gem. (#201)

Prevents "Rack::Handler is deprecated and replaced by Rackup::Handler" warning.

lib/rackup/handler/falcon.rb

@@ -0,0 +1,80 @@
+# frozen_string_literal: true
+
+require 'rackup/handler'
+
+require_relative '../../falcon'
+
+require 'kernel/sync'
+require 'async/io/host_endpoint'
+require 'async/io/notification'
+
+module Rackup
+	module Handler
+		# The falcon adaptor for the `rackup` executable.
+		class Falcon
+			# The default scheme.
+			SCHEME = "http"
+
+			# Generate an endpoint for the given `rackup` options.
+			# @returns [Async::IO::Endpoint]
+			def self.endpoint_for(**options)
+				host = options[:Host] || 'localhost'
+				port = Integer(options[:Port] || 9292)
+
+				return Async::IO::Endpoint.tcp(host, port)
+			end
+
+			# Run the specified app using the given options:
+			# @parameter app [Object] The rack middleware.
+			def self.run(app, **options)
+				app = ::Protocol::Rack::Adapter.new(app)
+
+				Sync do |task|
+					endpoint = endpoint_for(**options)
+					server = ::Falcon::Server.new(app, endpoint, protocol: Async::HTTP::Protocol::HTTP1, scheme: SCHEME)
+
+					server_task = task.async do
+						server.run.each(&:wait)
+					end
+
+					wrapper = self.new(server, task)
+
+					yield wrapper if block_given?
+
+					server_task.wait
+				ensure
+					server_task.stop
+					wrapper.close
+				end
+			end
+
+			def initialize(server, task)
+				@server = server
+				@task = task
+
+				@notification = Async::IO::Notification.new
+
+				@waiter = @task.async(transient: true) do
+					@notification.wait
+
+					@task&.stop
+					@task = nil
+				end
+			end
+
+			def stop
+				@notification&.signal
+			end
+
+			def close
+				@notification&.close
+				@notification = nil
+
+				@waiter&.stop
+				@waiter = nil
+			end
+		end
+
+		register :falcon, Falcon
+	end
+end