http://happstack.com/docs/crashcourse

install: cabal install happstack

helloworld:
	module Main where
	import Happstack.Server
	main :: IO ()
	main = simpleHTTP nullConf $ ok "Hello, World"
simpleHTTP :: (ToMessage a) => Conf -> ServerPartT IO a -> IO ()
data Conf, nullConf
ServerPartT
	ok String
	ok (toResponse String)

routing: 
	ServerPartT:
	msum [ mzero, ok "Hello", ok "Unreachable"]
	tries all parts until one succeeds
	mzero fails always
	match dir:
		[ dir "hello" $ ok "hello",
		dir "goodbye" $ dir "moon" $ ok "goodye",
		dirs "path/to" $ ok "sth"]
	path:
		[ dir "hello" $ path $ \s -> ok $ "Hello, " ++ s]
	FromReqURI instance to match more stuff
	match request method:
		methodM
		[ do methodM GET ok & ...,
		do methodM POST ok $ ...,
		dir "foo" $ do methodM GET ...
	allow unconsumed path segments:
		methodOnly
		[do methodM [GET, HEAD]
			ok $ "hey"
		]
	other routing filters:
		nullDir, host, withHost, uriRest, anyPath, trailingSlash

html:
	BlazeHtml, HSP, Hamlet, HStringTemplate, Heist, XSLT

request data:
	look, if it fails -> mzero
	always when processing post or put
		decodeBody myPolicy
		myPolicy = defaultBodyPolicy "/tmp/" 0 1000 1000
		then look
	forms should have enctype=multipart/form-data
	file uploads:
		lookFile
	other: getDataFn, lookRead

cookies:
	mkCookie, lookCookie, lookCookieValue, readCookieValue

state:
	at http://happstack.com/docs/crashcourse/HappstackState.html