Woah!

Woah! is an unobtrusive, (extremely) minimal web framework built on Rack.

gem install woah

You're gonna want to extend Woah::Base, which will be your app's, er, base.

require 'woah'

class MyApp < Woah::Base
end

MyApp.run!

You now have an app that serves 404 errors on every route. Not very useful, so let's extend that.

By the way, the lines require 'woah' and MyApp.run! will always be necessary, but to keep this file a little neater, they'll be omitted in the next examples. Just pretend they're there.

class MyApp < Woah::Base
	on '/hello' do
		"hey, what's up"
	end
end

When someone stumbles upon /hello now, they'll be greeted properly. Nice. These blocks of code are called routes. There's more types of blocks than just routes though. Check this out:

class MyApp < Woah::Base
	before do
		@@num ||= 1
	end

	on '/' do
		"this is the root of this app, and page hit nr. #{@@num}"
	end

	on '/hello' do
		"hey, what's up. this is page hit nr. #{@@num}"
	end

	after do
		@@num += 1
	end
end

There's two new blocks here: before and after. They do things before and after the relevant route gets executed. This example will increment a counter everytime a page is hit, regardless of what page it is.

Of course, getting pages isn't everything you can do on the Internet. There's other HTTP verbs as well, like POST. Behold:

class MyApp < Woah::Base
	before do
		@@content ||=
		'<form action="/" method="post">'\
			'<input type="submit" value="click me please" />'\
		'</form>'
	end

	on '/' do
		@@content
	end

	on '/', 'POST' do
		@@content = 'thanks for clicking!'
	end
end

As soon as you click the button on /, the message on the page will transform.

Of course, sometimes you want routes to be flexible, and to catch more than one expression. For this, you can use regular expressions instead of strings as your routes, just like this:

class MyApp < Woah::Base
	on %r{^/greet/(\w+)$} do
		"oh, hello, I didn't see you there #{match[1]}"
	end
end

Now, visiting /greet/Socrates will greet you with your own name (assuming your name is Socrates). Wonderful. By the way, you may have noticed the regex here is delimited by %r{}, instead of the more common //. This is because of how common slashes are in routes, so it's recommended to use this syntax. You can use slashes to delimit your regex though, if you like. I won't judge you.

Redirects are possible as well:

class MyApp < Woah::Base
	on '/' do
		redirect_to '/landing'
	end

	on '/landing' do
		'welcome'
	end
end

So are cookies:

class MyApp < Woah::Base
	on '/' do
		cookie 'chunky' || 'no cookie set'
	end

	on '/set' do
		cookie 'chunky', 'bacon'
	end

	on '/del' do
		cookie 'chunky', :delete
	end
end

Upon first visiting, this page will tell you there's no cookie set. After visiting /set however, it'll display bacon, as that is now the content of the chunky cookie. Visiting /del will delete the cookie again.

We're nearing the end of this little guide already, I'm afraid. However, there's still one more trick you need to see. Look, sometimes, you might disagree with the things Woah! thinks up for you. That's why you can override everything Woah! is about to send, if you so please. Por exemplo:

class MyApp < Woah::Base
	on '/' do
		'(insert super secret information)'
	end

	on %r{^/pass/(\w+)$} do
		@password = match[1]
		'logged in! <a href="/">back to root</a>'
	end

	after do
		unless @password && @password == 'penguin'
			set :status, 403
			set :body, 'log in first!'
		end
	end
end

That's all. Have fun!