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import Network.CGI
( CGI, CGIResult, runCGI, output, setCookie, newCookie, getCookie
)
import Text.XHtml
( Html, h1, p, header, body, (+++), thetitle, (<<), renderHtml
)
setCounterCookie :: Int -> CGI ()
setCounterCookie n = setCookie (newCookie "mycookie" (show n))
firstTime :: CGI [Html]
firstTime = do setCounterCookie 1
return [h1 << "Welcome!"]
returnVisitor :: Int -> CGI [Html]
returnVisitor c =
do setCounterCookie (c + 1)
return [h1 << "Welcome back!",
p << ("I have seen you " ++ show c ++ " times before.")]
cgiMain :: CGI CGIResult
cgiMain = do mc <- getCookie "mycookie"
h <- maybe firstTime (returnVisitor . read) mc
output $ renderHtml $ header << thetitle << "Cookie example"
+++ body << h
main :: IO ()
main = runCGI cgiMain
|
