From 9bea2e88fa7db10756353abcb4c7230af309085a Mon Sep 17 00:00:00 2001
From: stuebinm
Date: Fri, 19 Feb 2021 00:21:53 +0100
Subject: Send JSON instead of bare text

(before, the server just sent "state [n]" on state change, instead of
a properly serialised json value)
---
 Main.lhs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/Main.lhs b/Main.lhs
index 3799fbe..c05c2ab 100644
--- a/Main.lhs
+++ b/Main.lhs
@@ -63,6 +63,7 @@ are pretty boring:
 > data State = State { state :: Int } deriving (Show, Generic)
 > instance FromJSON Join
 > instance FromJSON State
+> instance ToJSON State
 
 Join is sent after a connection is established to indicate which room
 should be joined, State to indicate a state change
@@ -124,7 +125,7 @@ to the usual message handling loop, which just needs the room's state,
 not the server's global state:
 
 >           putStrLn $ show i <> " joined room " <> (show $ room join)
->           WS.sendTextData conn (T.pack $ "state " <> show n)
+>           WS.sendTextData conn $ encode State { state = n }
 >           talk (i, conn) roomstate
 
 Only one thing is still left to do, which is to define the `insertClient`
@@ -163,7 +164,7 @@ it did drop them).
 >       Left err -> putStrLn $ "json malformed" <> err
 >       Right new -> do
 >         peers <- modifyMVar roomstate $ \(cs,n) -> return ((cs, state new), cs)
->         broadcast ("state " <> (T.pack $ show $ state new)) peers
+>         broadcast (encode $ State { state = state new }) peers
 >     where
 >       disconnect i = do
 >         modifyMVar_ roomstate (\room -> return $ removeClient i room)
@@ -176,9 +177,9 @@ Note that this is a linked list (i.e. may be slow and cause some cache
 misses while iterating), but it's probably going to be fine unless there's
 a couple thousand clients in a room.
 
-> broadcast :: Text -> [Client] -> IO ()
+> broadcast :: LB.ByteString -> [Client] -> IO ()
 > broadcast message cs = do
->     --T.putStrLn message -- log messages
+>     LB.putStrLn message -- log messages
 >     forM_ cs $ \(_,conn) -> WS.sendTextData conn message
 
 
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