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haskellyesodhaskell-persistent

How do I respond with the value of a Key in Yesod?

I'm writing a REST API for a resource in Yesod. I have a POST method that should try to create the given resource and if successful return 201 and the ID of the newly created resource. E.g.,

postResourceR :: Handler String
postResourceR = do
  id <- runDB $ insert Resource
  sendResponseStatus status201 id -- DOES NOT COMPILE

Here's the error I get, which is plain enough:

No instance for (ToTypedContent (Key Resource))
  arising from use of 'sendResponseStatus'

I know I want something of the ToTypedContent, but I can't find any way to get that from a Key in Database.Persist.Class. Any help would be greatly appreciated.

EDIT:

Here's the definition of the actual resource:

Notification
    title Text
    content Text
    icon Text Maybe
    action Text Maybe 
    created UTCTime
    updated UTCTime
    deriving Show
Solution

  • Presuming you're using a SQL backend, you can use fromSqlKey. More generally you can use toBackendKey.