Convert get params into a haskell record

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Lookup content will take a list of values and parse them with a transformer into the right values. Then will map them into a JSON Object. To do this the final Data type must be an Instance of FromJSON and the transormer provided must convert (Text,Text) into a (Text,Val) type according to whatever Transformation rule you want

---

              
lookupContent ::(FromJSON a , MonadHandler m) => ( (Text,Text)  -> (Text,Value) ) -> m (Result a)
lookupContent objTransformer = do 
  req <- getRequest
  return $ fromJSON.object $ objTransformer <$> (reqGetParams req)

 
data TestObj =  TestObj { testWidth :: Int
                          ,testTitle :: Text 
                          ,testStep :: Int   
                       }
             deriving (Show,Eq)

instance FromJSON TestObj where 
    parseJSON (Object tObj) = TestObj <$> 
                          tObj .: "width" <*> 
                          tObj .: "title" <*> 
                          tObj .: "step" 

    parseJSON _ = fail "Rule: Expecting Test Object Received, Other"

instance ToJSON TestObj where 
    toJSON (TestObj {..}) = object 
                        [ 
                         "width" .= testWidth 
                         ,"step" .= testStep
                         ,"title" .= testTitle 
                         ]


-- | An example transformer on a get parameter string

exTransformObject :: (Text,Text) -> (Text, Value)
exTransformObject (t,v)
  | t == "width" = (t .= intVal v)
  | t == "title" = (t .=  textVal v)
  | t == "step"  = (t .=  intVal v)
  | otherwise = (t .= toJSON v)


-- | Helper functions to explicity do type conversion 

intVal :: Text -> Value
intVal = toJSON.intRead
         where
           intRead :: Text -> Int
           intRead = read . unpack


                     
textVal :: Text -> Value
textVal = toJSON