Dead links (like this one http://you.cant.click.this.com/) are magically transformed into live links! Rack::Linkify is very generous in what it considers a link; it will turn http://www.google.com, www.google.com, and just plain google.com into a link.

Rack::Linkify can also turn text that looks like @this into a twitter link.

This middleware highlights spelling errors in your web pages. It’s great for catching those silly typos before they reach the customer.

Rack::Steamroller completely flattens your web page into plain text. It even compresses multiple whitespace characters and newlines into a single space. While your end users will certainly not appreciate this middleware, it could be useful for automated regression testing.

This is a Rack middleware wrapper for gsub. You can replace text on your web page without worrying about accidentally modifying the HTML tags themselves.

Rack::EtyRack, don’t talk back.

This middleware only allows GET and HEAD HTTP methods through. If for some reason you think your web application is currently being attacked, you can quickly switch on this middleware. If your application is RESTful, this will prevent users from creating, modifying, or deleting data through the web application. Viewing data would still be allowed.

Warning: this code is untested.

The simplest Rack middleware ever.

I can think of at least one practical use for this middleware. Can you?

Never again will you accidentally delete production data! Rack::Environmental adds an indicator badge to your web application so that you can tell whether you’re working with the staging, test, development or production version of your web app.

Responds rudely to any 4xx client error except 404. Great addition to the Rack::RBL or BanHammer middlewares.