mu-haskell/adapter/persistent

mu-persistent

This are some utilities to integrate easily with persistent while using Mu.

Usage

Say you have for example, the following Entity:

mkPersist sqlSettings [persistLowerCase|
Person
  name T.Text
  age  Int32
  deriving Show Generic
|]

But in your proto3, the Person message is defined as:

message PersonRequest {
  int64 identifier = 1;
}

message Person {
  PersonRequest pid = 1;
  string name = 2;
  int32 age = 3;
}

How can you derive the correct ToSchema instances that Mu needs to work with that nested Id that belongs to another message? 🤔

You can use WithEntityNestedId, along with a custom field mapping and DerivingVia to do all the work for you!

{-# language DerivingVia #-}

type PersonFieldMapping
  = '[ "personAge" ':-> "age", "personName" ':-> "name" ]

deriving via (WithEntityNestedId "Person" PersonFieldMapping (Entity Person))
  instance ToSchema Maybe PersistentSchema "Person" (Entity Person)

For a more complete example of usage, please check the example with persistent.