Allow pathTo and parse to work with Maybe (Id record)

IHP/RouterSupport.hs

@@ -48,6 +48,7 @@ import GHC.TypeLits
 import Data.Data
 import qualified Control.Monad.State.Strict as State
 import qualified Data.Text as Text
+import qualified Data.UUID as UUID
 import Network.HTTP.Types.URI
 import qualified Data.List as List
 import Unsafe.Coerce
@@ -286,8 +287,24 @@ parseFuncs parseIdType = [
                     |> fromASCIIBytes
                     |> \case
                         Just uuid -> uuid |> unsafeCoerce |> Right
-                        Nothing -> Left BadType { field = "", value = Just queryValue, expectedType = "UUID" }
+                        Nothing ->
+                            -- We couldn't parse the UUID, so try Maybe (Id UUID),
+                            -- where we have a @Just@ prefix before the UUID, or a @Nothing@ string.
+                            if (cs queryValue == ("Nothing" :: Text))
+                                -- This is a @Nothing@
+                                then Nothing |> unsafeCoerce |> Right
+                                else
+                                    queryValue
+                                        |> cs
+                                        |> Text.replace "Just" ""
+                                        |> UUID.fromText
+                                        |> \case
+                                            -- We were able to parse the UUID, so wrap it in a @Just@.
+                                            Just uuid -> Just uuid |> unsafeCoerce |> Right
+                                            Nothing -> Left BadType { field = "", value = Just queryValue, expectedType = "UUID" }
+
                 Nothing -> Left NotMatched
+
             ]
 {-# INLINABLE parseFuncs #-}
 
@@ -645,7 +662,7 @@ instance {-# OVERLAPPABLE #-} (Show controller, AutoRoute controller) => HasPath
 -- | Parses the HTTP Method from the request and returns it.
 getMethod :: (?context :: RequestContext) => Parser StdMethod
 getMethod =
-    case parseMethod ?context.request.requestMethod of 
+    case parseMethod ?context.request.requestMethod of
         Left error -> fail (ByteString.unpack error)
         Right method -> pure method
 {-# INLINABLE getMethod #-}

Test/RouterSupportSpec.hs

@@ -66,6 +66,7 @@ data TestController
   | TestInteger { p1 :: Integer, p2 :: Maybe Integer, p3 :: [Integer] }
   | TestIntegerId { integerId :: Id Band }
   | TestUUIDId { uuidId :: Id Performance }
+  | TestMaybeUUIDId { maybeUuidId :: Maybe (Id Performance) }
   | TestUUIDList { uuidList :: [UUID] }
   deriving (Eq, Show, Data)
 
@@ -105,6 +106,10 @@ instance Controller TestController where
         renderPlain (cs $ ClassyPrelude.show integerId)
     action TestUUIDId { .. } = do
         renderPlain (cs $ ClassyPrelude.show uuidId)
+    action TestMaybeUUIDId { ..} =
+        case maybeUuidId of
+            Just uuidId -> renderPlain ("Just " <> cs (ClassyPrelude.show uuidId))
+            Nothing -> renderPlain "Nothing"
     action TestUUIDList { .. } = do
         renderPlain $ cs $ ClassyPrelude.show uuidList
 
@@ -193,6 +198,10 @@ tests = beforeAll (mockContextNoDatabase WebApplication config) do
             runSession (testGet "test/TestIntegerId?integerId=123") application >>= assertSuccess "123"
         it "parses Id with UUID param" $ withContext do
             runSession (testGet "test/TestUUIDId?uuidId=8dd57d19-490a-4323-8b94-6081ab93bf34") application >>= assertSuccess "8dd57d19-490a-4323-8b94-6081ab93bf34"
+        it "parses Maybe Id with UUID param: Nothing" $ withContext do
+            runSession (testGet "test/TestMaybeUUIDId?maybeUuidId=Nothing") application >>= assertSuccess "Nothing"
+        it "parses Maybe Id with UUID param: Just" $ withContext do
+            runSession (testGet "test/TestMaybeUUIDId?maybeUuidId=Just8dd57d19-490a-4323-8b94-6081ab93bf34") application >>= assertSuccess "Just 8dd57d19-490a-4323-8b94-6081ab93bf34"
         it "parses [UUID] param: empty" $ withContext do
             runSession (testGet "test/TestUUIDList") application >>= assertSuccess "[]"
         it "parses [UUID] param: one element" $ withContext do
@@ -218,8 +227,12 @@ tests = beforeAll (mockContextNoDatabase WebApplication config) do
             pathTo (TestTextListAction ["hello", "there"]) `shouldBe` "/test/TestTextList?textList=hello%2Cthere"
         it "generates correct path for [Int] param" $ withContext do
             pathTo (TestIntListAction [1,2,3]) `shouldBe` "/test/TestIntList?intList=1%2C2%2C3"
-        it "generates correct path for UUID param" $ withContext do
+        it "generates correct path for Id with UUID param" $ withContext do
             pathTo (TestUUIDId "8dd57d19-490a-4323-8b94-6081ab93bf34") `shouldBe` "/test/TestUUIDId?uuidId=8dd57d19-490a-4323-8b94-6081ab93bf34"
+        it "generates correct path for Maybe ID with UUID param: Nothing" $ withContext do
+            pathTo (TestMaybeUUIDId Nothing) `shouldBe` "/test/TestMaybeUUIDId?maybeUuidId=Nothing"
+        it "generates correct path for Maybe ID with UUID param: Just" $ withContext do
+            pathTo (TestMaybeUUIDId (Just "8dd57d19-490a-4323-8b94-6081ab93bf34")) `shouldBe` "/test/TestMaybeUUIDId?maybeUuidId=Just8dd57d19-490a-4323-8b94-6081ab93bf34"
         it "generates correct path for [UUID] param" $ withContext do
             pathTo (TestUUIDList ["8dd57d19-490a-4323-8b94-6081ab93bf34", "fdb15f8e-2fe9-441a-ae0e-da56956b1722"]) `shouldBe` "/test/TestUUIDList?uuidList=8dd57d19-490a-4323-8b94-6081ab93bf34%2Cfdb15f8e-2fe9-441a-ae0e-da56956b1722"
         it "generates correct path when used with Breadcrumbs" $ withContext do