Returning actual Data in Json

• Building out some hardcoded users





• need to supply User before the data





• don’t forget the = sign





• We could manually build the encode and decode to/from JSON, but Generics, lets you automatically do things based on the data type

  
  
  
  
  

  • adding {-# LANGUAGE DeriveGeneric #-} and import GHC.Generics

  
  
  

  • don’t forget to add instance

  
  
  

  • instance ToJSON User
    instance FromJSON User
    

  
  

Now we are able to see the output of having the generic encoder

Ok, two modules loaded.
*Main Lib> import Data.Aeson (encode)
*Main Lib Data.Aeson> encode bob
"{\"userName\":\"Bobby Boy\",\"userId\":1}"

• And now with that it looks like Scotty has a function json for use to return a json payload. sweet

    get "/users" $ do
        json allUsers

Resources

• Following this guide a bit


• Aeson


• Scotty

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• Jesse Tomchak
  
  
  
  
  • Twitter: @jtomchak