Add getLectureByIdCached function

README.md

@@ -3,3 +3,8 @@
 > lightweight squeak access
 
 Webserver that offers an HTML-only interface to Squeak.
+
+## TODO
+
+- Improve error handling: Write functions that turn `Maybe` and `Either` `SpockAction`s that return `4xx` or `5xx`.
+- Document JSON stuff

src/Lisa.hs

@@ -16,7 +16,7 @@ import Web.Internal.HttpApiData (FromHttpApiData)
 import Web.Spock (ActionCtxT, SpockM, get, lazyBytes, modifySession, param, post, readSession, redirect, request, root, setHeader, setStatus, text, var, (<//>))
 import Web.Spock.Config (PoolOrConn(PCNoDatabase), SpockCfg, defaultSpockCfg)
 
-import Lisa.Types (Session, State, getAllLecturesCached, emtpySession, mkState, setSessionAuthToken)
+import Lisa.Types (Session, State, getAllLecturesCached, getLectureByIdCached, emtpySession, mkState, setSessionAuthToken)
 
 import qualified Lisa.Squeak as Squeak
 import qualified Lisa.Views as Views
@@ -51,8 +51,9 @@ app = do
         blaze Views.viewIndex
     
     get ("lectures" <//> var) $ \lid -> do
+        lecture <- getLectureByIdCached lid
         documents <- Squeak.getDocumentsByLectureId lid
-        blaze $ either Views.viewSqueakError (Views.viewLecture lid) documents
+        blaze $ either Views.viewSqueakError id $ Views.viewLecture <$> lecture <*> documents
 
     get "lectures" $ do
         query <- fromMaybe "" <$> param "query"

src/Lisa/Types.hs

@@ -6,13 +6,14 @@ module Lisa.Types where
 
 import Control.Concurrent (MVar, newMVar, putMVar, takeMVar)
 import Control.Monad.IO.Class (liftIO)
+import Data.List (find)
 import Data.Text (Text)
 import Data.Time.Clock (UTCTime, addUTCTime, getCurrentTime)
 import Network.HTTP.Req (https)
 import Text.Printf (printf)
 import Web.Spock (SpockAction, getState, readSession)
 
-import Lisa.Squeak (Lecture, SqueakCtx, SqueakError)
+import Lisa.Squeak (Lecture(..), SqueakCtx, SqueakError(..))
 
 import qualified Lisa.Squeak as Squeak
 
@@ -61,6 +62,14 @@ getAllLecturesCached = do
     liftIO $ putMVar lecturesMVar newContents
     pure result
 
+getLectureByIdCached :: Text -> SpockAction conn Session State (Either SqueakError Lecture)
+getLectureByIdCached lid = do
+    lectures <- getAllLecturesCached
+    pure $ lectures >>= findLecture
+    where
+        findLecture =
+            maybe (Left $ SqueakError "LISA" "Lecture does not exist") Right . find ((lid ==) . lectureId)
+
 instance SqueakCtx (SpockAction conn Session State) where
     getLocationInfo = pure $ Right (https "api.squeak-test.fsmi.uni-karlsruhe.de", mempty)
     getAuthToken = fmap sessionAuthToken readSession

src/Lisa/Views.hs

@@ -36,9 +36,9 @@ viewLectures query lectures = do
         matchQuery (Lecture _id displayName aliases) =
             any (query `isInfixOf`) (displayName : aliases)
 
-viewLecture :: Text -> [Document] -> Html
+viewLecture :: Lecture -> [Document] -> Html
 viewLecture lecture documents = do
-    h1 $ text ("Vorlesung " <> lecture)
+    h1 $ text ("Vorlesung " <> lectureDisplayName lecture)
     table $ do
         thead $ tr $ mapM_ th ["Art", "Vorlesungen", "Prüfer", "Datum", "Semester", "Seiten"]
         tbody $ forM_ documents $ \document -> tr $ do