BadType routing failure in IHP even though types are defined

Question

Context

I have a record with a field that is of type Day (which corresponds to a field with type DATE in my Postgresql database). I have a Create action which works fine (records are saved to the database). However, from the Create action, if I try to redirect to another action and pass in the field with type Day like:

-- PostsController.hs
action CreatePostAction = do
    let post = newRecord @Post
            post
                |> buildPost
                |> ifValid \case
                    Left post -> do
                        render NewView { .. }
                    Right post -> do
                        let date1 = get #date1 post
                        redirectTo SomeAction { .. }
                

I get this error:

Query parameter "date1" needs to be a "UUID" but got "2021-10-16"

Routing failed with: BadType {expectedType = "UUID", value = Just "2021-10-23", field = "date1"}

even though SomeAction's param type is Day:

-- Types.hs
data PostsController = SomeAction { date1 :: Day }

Question

Why is the error thrown? And why is the expected type UUID when it should be Day?

Answer 1

IHP's AutoRoute only works with the following data types:

• Text
• [Text]
• Maybe Text
• Int
• [Int]
• Maybe Int
• Id

You can find more details in the docs: https://ihp.digitallyinduced.com/Guide/routing.html#parameter-types

I suggest that you use SomeAction { date1 :: Text } as a workaround. You could also use SomeAction without any explicit args and then access the date using param like this:

action SomeAction = do
    let date1 :: Day = param "date1"