<tt>ActionController::Dispatcher.new</tt> is the primary Rack application object of a Rails application. Any Rack compliant web server should be using +ActionController::Dispatcher.new+ object to serve a Rails application.
<tt>ApplicationName::Application</tt> is the primary Rack application object of a Rails application. Any Rack compliant web server should be using +ApplicationName::Application+ object to serve a Rails application.
h4. +rails server+
<tt>rails server</tt> does the basic job of creating a +Rack::Builder+ object and starting the webserver. This is Rails' equivalent of Rack's +rackup+ script.
<tt>rails server</tt> does the basic job of creating a +Rack::Server+ object and starting the webserver.
Here's how +rails server+ creates an instance of +Rack::Builder+
Here's how +rails server+ creates an instance of +Rack::Server+
<ruby>
app = Rack::Builder.new {
use Rails::Rack::LogTailer unless options[:detach]
use Rails::Rack::Debugger if options[:debugger]
use ActionDispatch::Static
run ActionController::Dispatcher.new
}.to_app
Rails::Server.new.tap { |server|
require APP_PATH
Dir.chdir(Rails.application.root)
server.start
}
</ruby>
Middlewares used in the code above are primarily useful only in the development environment. The following table explains their usage:
The +Rails::Server+ inherits from +Rack::Server+ and calls the +Rack::Server#start+ method this way:
<ruby>
class Server < ::Rack::Server
def start
...
super
end
end
</ruby>
Here's how it loads the middlewares:
<ruby>
def middleware
middlewares = []
middlewares << [Rails::Rack::Debugger] if options[:debugger]
middlewares << [::Rack::ContentLength]
Hash.new(middlewares)
end
</ruby>
+Rails::Rack::Debugger+ is primarily useful only in the development environment. The following table explains the usage of the loaded middlewares:
|_.Middleware|_.Purpose|
|+Rails::Rack::LogTailer+|Appends log file output to console|
|+Rack::ContentLength+|Counts the number of bytes in the response and set the HTTP Content-Length header|
h4. +rackup+
...
...
@@ -55,9 +75,9 @@ To use +rackup+ instead of Rails' +rails server+, you can put the following insi
# Rails.root/config.ru
require "config/environment"
use Rails::Rack::LogTailer
use ActionDispatch::Static
run ActionController::Dispatcher.new
use Rack::Debugger
use Rack::ContentLength
run ApplicationName::Application
</ruby>
And start the server:
...
...
@@ -72,11 +92,11 @@ To find out more about different +rackup+ options:
$ rackup --help
</shell>
h3. Action Controller Middleware Stack
h3. Action Dispatcher Middleware Stack
Many of Action Controller's internal components are implemented as Rack middlewares. +ActionController::Dispatcher+ uses +ActionController::MiddlewareStack+ to combine various internal and external middlewares to form a complete Rails Rack application.
Many of Action Dispatchers's internal components are implemented as Rack middlewares. +Rails::Application+ uses +ActionDispatch::MiddlewareStack+ to combine various internal and external middlewares to form a complete Rails Rack application.
NOTE: +ActionController::MiddlewareStack+ is Rails' equivalent of +Rack::Builder+, but built for better flexibility and more features to meet Rails' requirements.
NOTE: +ActionDispatch::MiddlewareStack+ is Rails' equivalent of +Rack::Builder+, but built for better flexibility and more features to meet Rails' requirements.
h4. Inspecting Middleware Stack
...
...
@@ -111,7 +131,7 @@ use ActionDispatch::Head
use Rack::ConditionalGet
use Rack::ETag
use ActionDispatch::BestStandardsSupport
run Blog::Application.routes
run ApplicationName::Application.routes
</ruby>
Purpose of each of this middlewares is explained in the "Internal Middlewares":#internal-middleware-stack section.
...
...
@@ -172,7 +192,7 @@ use ActionDispatch::Static
use #<ActiveSupport::Cache::Strategy::LocalCache::Middleware:0x00000001c304c8>
