Safe Haskell	None
Language	Haskell2010

Yesod.Persist.Core

Description

Defines the core functionality of this package. This package is distinguished from Yesod.Persist in that the latter additionally exports the persistent modules themselves.

Synopsis

class Monad (YesodDB site) => YesodPersist site where
- type YesodPersistBackend site
- runDB :: YesodDB site a -> HandlerFor site a
defaultRunDB :: PersistConfig c => (site -> c) -> (site -> PersistConfigPool c) -> PersistConfigBackend c (HandlerFor site) a -> HandlerFor site a
class YesodPersist site => YesodPersistRunner site where
- getDBRunner :: HandlerFor site (DBRunner site, HandlerFor site ())
defaultGetDBRunner :: (IsSqlBackend backend, YesodPersistBackend site ~ backend) => (site -> Pool backend) -> HandlerFor site (DBRunner site, HandlerFor site ())
newtype DBRunner site = DBRunner {
- runDBRunner :: forall a. YesodDB site a -> HandlerFor site a
}
runDBSource :: YesodPersistRunner site => ConduitT () a (YesodDB site) () -> ConduitT () a (HandlerFor site) ()
respondSourceDB :: YesodPersistRunner site => ContentType -> ConduitT () (Flush Builder) (YesodDB site) () -> HandlerFor site TypedContent
type YesodDB site = ReaderT (YesodPersistBackend site) (HandlerFor site)
get404 :: forall (m :: Type -> Type) backend val. (MonadIO m, PersistStoreRead backend, PersistRecordBackend val backend) => Key val -> ReaderT backend m val
getBy404 :: forall backend val (m :: Type -> Type). (PersistUniqueRead backend, PersistRecordBackend val backend, MonadIO m) => Unique val -> ReaderT backend m (Entity val)
insert400 :: forall (m :: Type -> Type) backend val. (MonadIO m, PersistUniqueWrite backend, PersistRecordBackend val backend, SafeToInsert val) => val -> ReaderT backend m (Key val)
insert400_ :: forall (m :: Type -> Type) backend val. (MonadIO m, PersistUniqueWrite backend, PersistRecordBackend val backend, SafeToInsert val) => val -> ReaderT backend m ()

Documentation

class Monad (YesodDB site) => YesodPersist site where #

Associated Types

type YesodPersistBackend site #

Methods

runDB :: YesodDB site a -> HandlerFor site a #

Allows you to execute database actions within Yesod Handlers. For databases that support it, code inside the action will run as an atomic transaction.

Example Usage

Expand

userId <- runDB $ do
  userId <- insert $ User "username" "email@example.com"
  insert_ $ UserPreferences userId True
  pure userId

defaultRunDB :: PersistConfig c => (site -> c) -> (site -> PersistConfigPool c) -> PersistConfigBackend c (HandlerFor site) a -> HandlerFor site a #

Helper for creating runDB.

Since 1.2.0

class YesodPersist site => YesodPersistRunner site where #

Since 1.2.0

Methods

getDBRunner :: HandlerFor site (DBRunner site, HandlerFor site ()) #

This function differs from runDB in that it returns a database runner function, as opposed to simply running a single action. This will usually mean that a connection is taken from a pool and then reused for each invocation. This can be useful for creating streaming responses; see runDBSource.

It additionally returns a cleanup function to free the connection. If your code finishes successfully, you must call this cleanup to indicate changes should be committed. Otherwise, for SQL backends at least, a rollback will be used instead.

Since 1.2.0

defaultGetDBRunner :: (IsSqlBackend backend, YesodPersistBackend site ~ backend) => (site -> Pool backend) -> HandlerFor site (DBRunner site, HandlerFor site ()) #

Helper for implementing getDBRunner.

Since 1.2.0

newtype DBRunner site #

Constructors

DBRunner
Fields runDBRunner :: forall a. YesodDB site a -> HandlerFor site a

runDBSource :: YesodPersistRunner site => ConduitT () a (YesodDB site) () -> ConduitT () a (HandlerFor site) () #

Like runDB, but transforms a Source. See respondSourceDB for an example, practical use case.

Since 1.2.0

respondSourceDB :: YesodPersistRunner site => ContentType -> ConduitT () (Flush Builder) (YesodDB site) () -> HandlerFor site TypedContent #

Extends respondSource to create a streaming database response body.

type YesodDB site = ReaderT (YesodPersistBackend site) (HandlerFor site) #

get404 :: forall (m :: Type -> Type) backend val. (MonadIO m, PersistStoreRead backend, PersistRecordBackend val backend) => Key val -> ReaderT backend m val #

Get the given entity by ID, or return a 404 not found if it doesn't exist.

getBy404 :: forall backend val (m :: Type -> Type). (PersistUniqueRead backend, PersistRecordBackend val backend, MonadIO m) => Unique val -> ReaderT backend m (Entity val) #

Get the given entity by unique key, or return a 404 not found if it doesn't exist.

insert400 :: forall (m :: Type -> Type) backend val. (MonadIO m, PersistUniqueWrite backend, PersistRecordBackend val backend, SafeToInsert val) => val -> ReaderT backend m (Key val) #

Create a new record in the database, returning an automatically created key, or raise a 400 bad request if a uniqueness constraint is violated.

Since: 1.4.1

insert400_ :: forall (m :: Type -> Type) backend val. (MonadIO m, PersistUniqueWrite backend, PersistRecordBackend val backend, SafeToInsert val) => val -> ReaderT backend m () #

Same as insert400, but doesn’t return a key.

Since: 1.4.1