Saving search query using MVar and waiting for that MVar on form submit

src/Component/Search.hs

@@ -25,22 +25,34 @@ import Miso
   , (<#)
   , consoleLog
   , noEff
-  , batchEff
   )
 import Data.JSString (pack)
 import qualified Network.Client as Client
 import Network.Http (HttpResult (..))
+import Control.Concurrent.MVar (tryTakeMVar, takeMVar, putMVar, swapMVar)
+
 import Component.Search.SearchTypes
 
 update :: Interface a -> Action -> Model -> Effect a Model
 update iface (SearchChange q) model = model { searchTerm = q } <# do
-    consoleLog q
+    consoleLog $ "SearchChange " <> q
+    m_search_query <- tryTakeMVar (searchVar model)
+
+    case m_search_query of
+        Nothing -> putMVar (searchVar model) q
+        Just _ -> swapMVar (searchVar model) q >> return ()
+
     return $ (passAction iface) NoAction
 
-update iface (OnSubmit search_query) model = model { searchTerm = search_query } <# do
+update iface OnSubmit model = model <# do
+    search_query <- takeMVar (searchVar model)
     consoleLog $ "Submit! " <> search_query
     Client.search (clientModel model) search_query (clientIface iface)
 
+update iface (ChangeAndSubmit search_query) model = model { searchTerm = search_query } <# do
+    _ <- swapMVar (searchVar model) search_query
+    return $ (passAction iface) OnSubmit
+
 update iface (SearchResult result) model = model <# do
     consoleLog $ "Received search results!"
 
@@ -62,12 +74,13 @@ update iface (PassPostsToSelf search_results) model = model { displayResults = s
 
 update _ NoAction m = noEff m
 
+
 view :: Interface a -> Model -> View a
 view iface m = form_
     [ class_ "search_form"
     , action_ "/search"
     , method_ "GET"
-    , onSubmit $ pass $ OnSubmit $ searchTerm m
+    , onSubmit $ pass $ OnSubmit
     ]
     [ input_
         [ type_ "submit"

src/Component/Search/SearchTypes.hs

@@ -2,19 +2,22 @@ module Component.Search.SearchTypes where
 
 import Data.JSString (JSString)
 import Network.Http (HttpResult (..))
+import Control.Concurrent.MVar (MVar)
 
 import qualified Network.ClientTypes as Client
 import Network.CatalogPostType (CatalogPost)
 
 data Action
     = SearchChange JSString
-    | OnSubmit JSString
+    | OnSubmit
+    | ChangeAndSubmit JSString
     | SearchResult (HttpResult [ CatalogPost ])
     | PassPostsToSelf [ CatalogPost ] -- I think I don't understand something about the update type but I had to add this...
     | NoAction
 
 data Model = Model
     { searchTerm :: JSString
+    , searchVar :: MVar JSString
     , clientModel :: Client.Model
     , displayResults :: [ CatalogPost ]
     } deriving Eq

src/Main.hs

@@ -12,6 +12,7 @@ import qualified Data.Text as T
 import Network.URI (uriPath, uriQuery, escapeURIString, unEscapeString, isAllowedInURI)
 import System.FilePath ((</>))
 import Data.Time.Clock (UTCTime, getCurrentTime)
+import Control.Concurrent.MVar (MVar, newEmptyMVar)
 
 import Data.Aeson (FromJSON)
 import Data.JSString (pack, append, unpack)
@@ -51,7 +52,6 @@ import qualified Component.CatalogGrid as Grid
 import qualified Component.ThreadView as Thread
 import qualified Component.TimeControl as TC
 import qualified Component.Search as Search
-import qualified Component.Search.SearchTypes as Search
 
 
 data Model = Model
@@ -89,10 +89,10 @@ initialActionFromRoute model uri = either (const NoAction) id routing_result
         h_thread website board_pathpart board_thread_id _ = GetThread GetThreadArgs {..}
 
         h_search :: Maybe Text -> Model -> Action
-        h_search Nothing model = GoToTime $ current_time model
+        h_search Nothing m = GoToTime $ current_time m
-        h_search (Just search_query) model
+        h_search (Just search_query) m
-            | Search.searchTerm (search_model model) == unescaped_search_query = SearchResults unescaped_search_query
+            | Search.searchTerm (search_model m) == unescaped_search_query = SearchResults unescaped_search_query
-            | otherwise = (Search.passAction iSearch) $ Search.OnSubmit $ toJSString $ T.unpack search_query
+            | otherwise = (Search.passAction iSearch) $ Search.ChangeAndSubmit unescaped_search_query
 
             where
                 unescaped_search_query = toJSString $ unEscapeString $ T.unpack search_query
@@ -104,8 +104,9 @@ initialModel
     -> JSString
     -> URI
     -> UTCTime
+    -> MVar JSString
     -> Model
-initialModel pgroot client_fetch_count media_root u t = Model
+initialModel pgroot client_fetch_count media_root u t smv = Model
     { grid_model = Grid.initialModel media_root
     , client_model = client_model_
     , thread_model = Nothing
@@ -115,6 +116,7 @@ initialModel pgroot client_fetch_count media_root u t = Model
     , tc_model = TC.initialModel 0
     , search_model = Search.Model
         { Search.searchTerm = ""
+        , Search.searchVar = smv
         , Search.clientModel = client_model_
         , Search.displayResults = []
         }
@@ -160,11 +162,14 @@ main = do
 
     now <- getCurrentTime
 
+    search_var <- newEmptyMVar
+
     let initial_model = initialModel
           pg_api_root
           pg_fetch_count
           media_root uri
           now
+          search_var
 
     startApp App
         { model         = initial_model
@@ -285,6 +290,7 @@ mainUpdate (SearchAction sa) m =
   >>= \sm -> noEff m { search_model = sm }
 
 mainUpdate (SearchResults query) m = m { current_uri = new_current_uri } <# do
+    consoleLog $ "SearchResults new uri: " <> (pack $ show new_current_uri)
     pushURI new_current_uri
     return NoAction
 
@@ -328,6 +334,6 @@ iSearch :: Search.Interface Action
 iSearch =
   Search.Interface
     { passAction = SearchAction
-    , clientIface = iClient (SearchAction . Search.SearchResult)
+    , clientIface = iClient $ SearchAction . Search.SearchResult
     , searchResults = SearchResults
     }