112 lines
4.2 KiB
Haskell
112 lines
4.2 KiB
Haskell
{-# LANGUAGE QuasiQuotes, TemplateHaskell, TypeFamilies, OverloadedStrings, ScopedTypeVariables #-}
|
|
import Yesod.Core
|
|
import Yesod.WebSockets
|
|
import qualified Data.Text.Lazy as TL
|
|
import Control.Monad (forever)
|
|
import Control.Monad.Trans.Reader
|
|
import Control.Concurrent (threadDelay)
|
|
import Data.Time
|
|
import Conduit
|
|
import Data.Monoid ((<>))
|
|
import Control.Concurrent.STM.Lifted
|
|
import Data.Text (Text)
|
|
import UnliftIO.Exception (try, SomeException)
|
|
|
|
data App = App (TChan Text)
|
|
|
|
mkYesod "App" [parseRoutes|
|
|
/ HomeR GET
|
|
|]
|
|
|
|
instance Yesod App
|
|
|
|
chatApp :: WebSocketsT Handler ()
|
|
chatApp = do
|
|
sendTextData ("Welcome to the chat server, please enter your name." :: Text)
|
|
name <- receiveData
|
|
sendTextData $ "Welcome, " <> name
|
|
App writeChan <- getYesod
|
|
readChan <- atomically $ do
|
|
writeTChan writeChan $ name <> " has joined the chat"
|
|
dupTChan writeChan
|
|
(e :: Either SomeException ()) <- try $ race_
|
|
(forever $ atomically (readTChan readChan) >>= sendTextData)
|
|
(sourceWS $$ mapM_C (\msg ->
|
|
atomically $ writeTChan writeChan $ name <> ": " <> msg))
|
|
|
|
atomically $ case e of
|
|
Left _ -> writeTChan writeChan $ name <> " has left the chat"
|
|
Right () -> return ()
|
|
|
|
getHomeR :: Handler Html
|
|
getHomeR = do
|
|
webSockets chatApp
|
|
defaultLayout $ do
|
|
[whamlet|
|
|
<div #output>
|
|
<form #form>
|
|
<input #input autofocus>
|
|
|]
|
|
toWidget [lucius|
|
|
\#output {
|
|
width: 600px;
|
|
height: 400px;
|
|
border: 1px solid black;
|
|
margin-bottom: 1em;
|
|
p {
|
|
margin: 0 0 0.5em 0;
|
|
padding: 0 0 0.5em 0;
|
|
border-bottom: 1px dashed #99aa99;
|
|
}
|
|
}
|
|
\#input {
|
|
width: 600px;
|
|
display: block;
|
|
}
|
|
|]
|
|
toWidget [julius|
|
|
var url = document.URL,
|
|
output = document.getElementById("output"),
|
|
form = document.getElementById("form"),
|
|
input = document.getElementById("input"),
|
|
conn;
|
|
|
|
url = url.replace("http:", "ws:").replace("https:", "wss:");
|
|
conn = new WebSocket(url);
|
|
|
|
conn.onmessage = function(e) {
|
|
var p = document.createElement("p");
|
|
p.appendChild(document.createTextNode(e.data));
|
|
output.appendChild(p);
|
|
};
|
|
/* *******************************************************************************************************
|
|
The following code demonstrates one way to prevent timeouts. The "if" test is added to prevent chat participants from getting the ping message “dcba” every twenty seconds. It also prevents participants from receiving any message ending with “dcba” sent by any chat participant. “ e.data.split("").reverse().join("").substring(0,4)” changes, for example, “user:abc123dcba” to “abcd321cba:resu” and grabs the first four characters; i.e., “abcd”. Messages are broadcast only if the last four characters are not “dcba”. Note that the variable "t" controls the length of the timeout period. t = 3 allows one minute of inactivity. t = 30 allows ten minutes, and t = 180 allows an hour. The value inserted below is 360 (2 hours).
|
|
*/
|
|
conn.onmessage = function(e) {
|
|
var p = document.createElement("p");
|
|
p.appendChild(document.createTextNode(e.data));
|
|
if (e.data.split("").reverse().join("").substring(0,4) != "abcd") {
|
|
output.appendChild(p);
|
|
}
|
|
};
|
|
var t = 360
|
|
setInterval (function () {
|
|
t = t - 1;
|
|
if (t > 0)
|
|
{
|
|
conn.send("dcba");
|
|
}
|
|
}, 20000);
|
|
/* ****************************************************************************************************** */
|
|
form.addEventListener("submit", function(e){
|
|
conn.send(input.value);
|
|
input.value = "";
|
|
e.preventDefault();
|
|
});
|
|
|]
|
|
|
|
main :: IO ()
|
|
main = do
|
|
chan <- atomically newBroadcastTChan
|
|
warp 3000 $ App chan
|