purescript-apiary: A PureScript repository from robertdp

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It's hard to be a busy little bee when working with unspec'ed APIs. This library is designed for the creation of type-level specs that can be queried against automatically!

Example

type User
  = { id :: Int
    , name :: String
    , email :: String
    }

type ListUsers
  = GET "/users"
      { query ::
        { sortBy :: UserSort
        , sortDir :: SortDir
        }
      , response ::
        { ok :: JSON (Array User)
        }
      }

type CreateNewUser
  = POST "/users"
      { body :: JSON { name :: String, email :: String }
      , response ::
        { ok :: JSON User
        , badRequest :: JSON { errors :: Array { field :: String, message :: String } }
        }
      }

listUsers params =
  Apiary.makeRequest (Route :: ListUsers) identity params none

createNewUser body =
  Apiary.makeRequest (Route :: CreateNewUser) identity none body

This will give us inferred types equivalent to

listUsers ::
  { sortBy :: Maybe UserSort, sortDir :: Maybe SortDir } ->
  Aff (Either Apiary.Error (Variant ( ok :: Array User )))

createNewUser ::
  { name :: String, email :: String } ->
  Aff
    (Either Apiary.Error
      (Variant
        ( ok :: User
        , badRequest :: { errors :: Array { field :: String, message :: String } }
        )
      )
    )

Here is an example with URL modification and JWT-based authorisation inspired by some production code:

makeSecureRequest ::
  forall m r route params body rep response.
  MonadAff m =>
  MonadAsk { baseUrl :: String, token :: String | r } m =>
  Apiary.BuildRequest route params body rep =>
  Apiary.DecodeResponse rep response =>
  route ->
  params ->
  body ->
  m (Either Apiary.Error response)
makeSecureRequest route params body = do
  env <- ask
  liftAff $ mkRequest (addBaseUrl env.baseUrl <<< addToken env.token)
  where

  mkRequest modify =
    Apiary.makeRequest route modify params body

  addToken token request@{ headers } =
    request { headers = Object.insert "Authorization" ("Bearer " <> token) headers }

  addBaseUrl baseUrl request@{ url: URL url } =
    request { url = URL (baseUrl <> url) }

type AppM = ReaderT { baseUrl :: String, token :: String } Aff

listUsers ::
  { sortBy :: Maybe UserSort, sortDir :: Maybe SortDir } ->
  AppM (Either Apiary.Error (Variant ( ok :: Array User )))
listUsers params =
  makeSecureRequest (Route :: ListUsers) params unit

robertdp/purescript-apiary

Example