Learning Rails

What Server Is That?

You might wonder what server is running your Rails application—after all, nothing so far has required any configuration, despite the fairly complicated usual installs needed to get web programming environments to run. You can continue without knowing (until it’s time for real deployment), but if you’re curious, here are the details.

Note

Heroku doesn’t say which server it’s using, but fortunately that doesn’t matter very much for getting things done.

You may be familiar with Apache or Microsoft’s Internet Information Server (IIS), but neither of those web servers is probably running these Rails programs. (They can run Rails, but unless you took a very different path for installation, they’re not running yet.) Instead, your programs are probably running in Mongrel. The Rails 2.0 command line uses Mongrel. (In earlier versions of Rails, running the application from the command line in the usual way started up an instance of WEBrick.) Instant Rails uses Apache with Mongrel actually interacting with Rails behind it. WEBrick and Mongrel come with slightly different priorities:

WEBrick (http://www.webrick.org/)

WEBrick is written in Ruby and bundled with recent releases of Ruby. It’s very convenient for Ruby development, with or without Rails. It’s an excellent testing server, but not designed for large scale deployment.

Mongrel (http://mongrel.rubyforge.org/)

Mongrel is a highly optimized server written in Ruby that “does the bare minimum necessary to serve a Ruby application.” ...