servant-db-postgresql: Derive a postgres client to database API specified by servant-db

Versions [RSS]	0.2.0.0, 0.2.0.1, 0.2.1.0, 0.2.2.0
Change log	CHANGELOG.md
Dependencies	base (>=4.7 && <5), bytestring (>=0.10 && <0.11), containers (>=0.5 && <0.6), monad-logger (>=0.3 && <0.4), postgresql-query (>=3.0 && <3.2), postgresql-simple (>=0.5 && <0.6), servant (>=0.9 && <0.10), servant-db (>=0.2 && <0.3), servant-db-postgresql, text (>=1.2 && <1.3), time, transformers-base (>=0.4 && <0.5) [details]
License	BSD-3-Clause
Copyright	2016 (c) Anton Gushcha
Author	Anton Gushcha
Maintainer	ncrashed@gmail.com
Category	Database
Home page	https://github.com/NCrashed/servant-db-postgresql
Source repo	head: git clone https://github.com/NCrashed/servant-db-postgresql.git
Uploaded	by NCrashed at 2017-03-15T11:34:54Z
Distributions
Reverse Dependencies	1 direct, 0 indirect [details]
Executables	servant-db-postgresql-example01
Downloads	2604 total (4 in the last 30 days)
Rating	(no votes yet) [estimated by Bayesian average]
Your Rating	λ λ λ
Status	Docs available [build log] Last success reported on 2017-03-15 [all 1 reports]

Readme for servant-db-postgresql-0.2.2.0

[back to package description]

servant-db-postgresql

Automatic derive of typed DB API based on postgresql-query package.

How to use:

Define your instances of MonadLogger and HasPostgres for your app monad:

newtype PostgresM a = PostgresM { runPostgresM :: PgMonadT (LoggingT IO) a }
  deriving (Functor, HasPostgres, MonadLogger, Monad, Applicative, MonadBase IO)

Define type level API:

type UserId = Int

data RegisterUser = RegisterUser {
  userRegName     :: String
, userRegPassword :: String
, userRegRegTime  :: Day
} deriving (Eq)

deriveToRow ''RegisterUser

data User = User {
  userId       :: UserId
, userName     :: String
, userPassword :: String
, userRegTime  :: Day
} deriving (Eq)

deriveFromRow ''User
deriveToRow ''User

type UserAPI =
       ArgNamed "u" (Composite RegisterUser)
    :> Procedure "postUser" (Only Int)
  :<|> ArgPos Int
    :> Procedure "getUser" (Maybe User)
  :<|> ArgPos Int
    :> Procedure "deleteUser" ()
  :<|> Procedure "getUsers" [User]

Derive client functions from the API:

postUser :: Composite RegisterUser -> PostgresM (Only Int)
getUser :: Int -> PostgresM (Maybe User)
deleteUser :: Int -> PostgresM ()
getUsers :: PostgresM [User]
(      postUser
  :<|> getUser
  :<|> deleteUser
  :<|> getUsers) = deriveDB (Proxy :: Proxy UserAPI) (Proxy :: Proxy PostgresM)

Use them. The full example you can view at example01/Main.hs module. And to compile it run the:

stack build --flag servant-db-postgresql:examples

Features

Call functions in schema with :> operator:

type API = "test" :> ArgPos Int :> Procedure "square" (Only Int)

That will call function test.square(int).

Composite types are defined with Composite a wrapper:

type API = ArgNamed "u" (Composite UserCreate) :> Procedure "postUser" (Only Int)

Support for arrays:

type API = ArgPos (PGArray Int) :> Procedure "mleast" (Maybe (Only Int))

Support for variadic arguments:

type API = ArgPos (Variadic Int) :> Procedure "mleast" (Maybe (Only Int))

Support for default arguments with newypte Default a = Default (Maybe a):

type API = ArgPos (Default Int) :> Procedure "foo" (Only Int)