Create chat-with-timeout-control.hs

2014-10-06 20:56:08 -04:00 · 2014-10-06 20:56:08 -04:00 · 8caa9f087b
commit 8caa9f087b
parent dece47fe9e
1 changed files with 106 additions and 0 deletions
--- a/yesod-websockets/chat-with-timeout-control.hs
+++ b/yesod-websockets/chat-with-timeout-control.hs
@ -0,0 +1,106 @@
+{-# LANGUAGE QuasiQuotes, TemplateHaskell, TypeFamilies, OverloadedStrings #-}
+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)
+
+data App = App (TChan Text)
+
+instance Yesod App
+
+mkYesod "App" [parseRoutes|
+/ HomeR GET
+|]
+
+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
+    race_
+        (forever $ atomically (readTChan readChan) >>= sendTextData)
+        (sourceWS $$ mapM_C (\msg ->
+            atomically $ writeTChan writeChan $ name <> ": " <> msg))
+
+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