Add Rack handler for 'rails server' integration

CHANGELOG

@@ -2,6 +2,7 @@ Release 5.0.25
 --------------
 
  * Fixes a crash that occurs when using Nginx + HTTPS + Sub-requests. Closes GH-1724.
+ * Integrates into the `rails server` command. Please learn more at [the Passenger + Rails integration documentation](https://www.phusionpassenger.com/library/dev/ruby/rails_integration.html).
  * [Standalone] Makes the `--address` option work more reliably if the passed hostname may resolve to multiple addresses. For example, if you pass `--address localhost` then previous versions could fail because Passenger thinks it's an IPv6 address (::1) while Nginx thinks it's an IPv6 address (127.0.0.1). Hostname resolution is now done in a consistent manner.
  * [Standalone] Adds IPv6 support to the builtin engine.
 

src/ruby_supportlib/phusion_passenger/rack_handler.rb

@@ -0,0 +1,102 @@
+#  Phusion Passenger - https://www.phusionpassenger.com/
+#  Copyright (c) 2016 Phusion Holding B.V.
+#
+#  "Passenger", "Phusion Passenger" and "Union Station" are registered
+#  trademarks of Phusion Holding B.V.
+#
+#  Permission is hereby granted, free of charge, to any person obtaining a copy
+#  of this software and associated documentation files (the "Software"), to deal
+#  in the Software without restriction, including without limitation the rights
+#  to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+#  copies of the Software, and to permit persons to whom the Software is
+#  furnished to do so, subject to the following conditions:
+#
+#  The above copyright notice and this permission notice shall be included in
+#  all copies or substantial portions of the Software.
+#
+#  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+#  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+#  FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+#  AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+#  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+#  OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+#  THE SOFTWARE.
+
+## Magic comment: begin bootstrap ##
+libdir = File.expand_path('..', File.dirname(__FILE__))
+$LOAD_PATH.unshift(libdir)
+begin
+  require 'rubygems'
+rescue LoadError
+end
+require 'phusion_passenger'
+## Magic comment: end bootstrap ##
+
+PhusionPassenger.locate_directories
+
+require 'rbconfig'
+
+module Rack
+  module Handler
+    class PhusionPassenger
+      class << self
+        def run(app, options = {})
+          result = system(ruby_executable, '-S', find_passenger_standalone,
+            'start', *build_args(options))
+          if !result
+            raise "Error starting Passenger"
+          end
+        end
+
+        def environment
+          ENV['RAILS_ENV'] || 'development'
+        end
+
+        def to_s
+          'Passenger application server'
+        end
+
+      private
+        def build_args(options)
+          args = ['-e', environment]
+          if options[:Port]
+            args << '-p'
+            args << options[:Port].to_s
+          end
+          if options[:Host]
+            args << '-a'
+            args << options[:Host].to_s
+          end
+          if options[:config]
+            args << '-R'
+            args << options[:config].to_s
+          end
+          args
+        end
+
+        def rb_config
+          if defined?(::RbConfig)
+            ::RbConfig::CONFIG
+          else
+            ::Config::CONFIG
+          end
+        end
+
+        def ruby_executable
+          @ruby_executable ||= rb_config['bindir'] + '/' +
+            rb_config['RUBY_INSTALL_NAME'] + rb_config['EXEEXT']
+        end
+
+        def find_passenger_standalone
+          ::File.join(::PhusionPassenger.bin_dir, 'passenger')
+        end
+      end
+    end
+
+    register 'passenger', 'Rack::Handler::PhusionPassenger'
+
+    def self.default(options = {})
+      Rack::Handler::PhusionPassenger
+    end
+  end
+end