Safe Haskell	None
Language	Haskell2010

Servant.Server

Contents

Run a wai application from an API
Construct a wai Application from an API
Handlers for all standard combinators
Debugging the server layout
Enter / hoisting server
- Functions based on mmorph
Context
- NamedContext
Basic Authentication
General Authentication
Default error type
- 3XX
- 4XX
- 5XX
Re-exports

Description

This module lets you implement Servers for defined APIs. You'll most likely just need serve.

Synopsis

serve :: HasServer api '[] => Proxy api -> Server api -> Application
serveWithContext :: HasServer api context => Proxy api -> Context context -> Server api -> Application
toApplication :: RoutingApplication -> Application
class HasServer api context where
- type ServerT api (m :: * -> *) :: *
- route :: Proxy api -> Context context -> Delayed env (Server api) -> Router env
- hoistServerWithContext :: Proxy api -> Proxy context -> (forall x. m x -> n x) -> ServerT api m -> ServerT api n
type Server api = ServerT api Handler
data EmptyServer
emptyServer :: ServerT EmptyAPI m
newtype Handler a = Handler {
- runHandler' :: ExceptT ServantErr IO a
}
runHandler :: Handler a -> IO (Either ServantErr a)
layout :: HasServer api '[] => Proxy api -> Text
layoutWithContext :: HasServer api context => Proxy api -> Context context -> Text
hoistServer :: HasServer api '[] => Proxy api -> (forall x. m x -> n x) -> ServerT api m -> ServerT api n
tweakResponse :: (RouteResult Response -> RouteResult Response) -> Router env -> Router env
data Context contextTypes where
- EmptyContext :: Context '[]
- (:.) :: x -> Context xs -> Context (x ': xs)
class HasContextEntry (context :: [*]) (val :: *) where
- getContextEntry :: Context context -> val
data NamedContext (name :: Symbol) (subContext :: [*]) = NamedContext (Context subContext)
descendIntoNamedContext :: forall context name subContext. HasContextEntry context (NamedContext name subContext) => Proxy (name :: Symbol) -> Context context -> Context subContext
newtype BasicAuthCheck usr = BasicAuthCheck {
- unBasicAuthCheck :: BasicAuthData -> IO (BasicAuthResult usr)
}
data BasicAuthResult usr
- = Unauthorized
- | BadPassword
- | NoSuchUser
- | Authorized usr
data ServantErr = ServantErr {
- errHTTPCode :: Int
- errReasonPhrase :: String
- errBody :: ByteString
- errHeaders :: [Header]
}
err300 :: ServantErr
err301 :: ServantErr
err302 :: ServantErr
err303 :: ServantErr
err304 :: ServantErr
err305 :: ServantErr
err307 :: ServantErr
err400 :: ServantErr
err401 :: ServantErr
err402 :: ServantErr
err403 :: ServantErr
err404 :: ServantErr
err405 :: ServantErr
err406 :: ServantErr
err407 :: ServantErr
err409 :: ServantErr
err410 :: ServantErr
err411 :: ServantErr
err412 :: ServantErr
err413 :: ServantErr
err414 :: ServantErr
err415 :: ServantErr
err416 :: ServantErr
err417 :: ServantErr
err418 :: ServantErr
err422 :: ServantErr
err500 :: ServantErr
err501 :: ServantErr
err502 :: ServantErr
err503 :: ServantErr
err504 :: ServantErr
err505 :: ServantErr
type Application = Request -> (Response -> IO ResponseReceived) -> IO ResponseReceived
newtype Tagged (s :: k) b :: forall k. k -> Type -> Type = Tagged {
- unTagged :: b
}

Run a wai application from an API

serve :: HasServer api '[] => Proxy api -> Server api -> Application Source #

serve allows you to implement an API and produce a wai Application.

Example:

type MyApi = "books" :> Get '[JSON] [Book] -- GET /books
        :<|> "books" :> ReqBody Book :> Post '[JSON] Book -- POST /books

server :: Server MyApi
server = listAllBooks :<|> postBook
  where listAllBooks = ...
        postBook book = ...

myApi :: Proxy MyApi
myApi = Proxy

app :: Application
app = serve myApi server

main :: IO ()
main = Network.Wai.Handler.Warp.run 8080 app

serveWithContext :: HasServer api context => Proxy api -> Context context -> Server api -> Application Source #

Construct a wai Application from an API

toApplication :: RoutingApplication -> Application Source #

Handlers for all standard combinators

class HasServer api context where Source #

Associated Types

type ServerT api (m :: * -> *) :: * Source #

Methods

route :: Proxy api -> Context context -> Delayed env (Server api) -> Router env Source #

hoistServerWithContext :: Proxy api -> Proxy context -> (forall x. m x -> n x) -> ServerT api m -> ServerT api n Source #

Instances

HasServer Raw context Source #	Just pass the request to the underlying application and serve its response. Example: type MyApi = "images" :> Raw server :: Server MyApi server = serveDirectory "/var/www/images"
Instance details Defined in Servant.Server.Internal Associated Types type ServerT Raw m :: Type Source # Methods route :: Proxy Raw -> Context context -> Delayed env (Server Raw) -> Router env Source # hoistServerWithContext :: Proxy Raw -> Proxy context -> (forall x. m x -> n x) -> ServerT Raw m -> ServerT Raw n Source #
HasServer EmptyAPI context Source #	The server for an `EmptyAPI` is `emptyAPIServer`. type MyApi = "nothing" :> EmptyApi server :: Server MyApi server = emptyAPIServer
Instance details Defined in Servant.Server.Internal Associated Types type ServerT EmptyAPI m :: Type Source # Methods route :: Proxy EmptyAPI -> Context context -> Delayed env (Server EmptyAPI) -> Router env Source # hoistServerWithContext :: Proxy EmptyAPI -> Proxy context -> (forall x. m x -> n x) -> ServerT EmptyAPI m -> ServerT EmptyAPI n Source #
(TypeError (HasServerArrowTypeError a b) :: Constraint) => HasServer (a -> b :: Type) context Source #	This instance prevents from accidentally using '->' instead of `:>` `>>>` `serve (Proxy :: Proxy (Capture "foo" Int -> Get '[JSON] Int)) (error "...")`... ...No instance HasServer (a -> b). ...Maybe you have used '->' instead of ':>' between ...Capture' '[] "foo" Int ...and ...Verb 'GET 200 '[JSON] Int ... `>>>` `undefined :: Server (Capture "foo" Int -> Get '[JSON] Int)`... ...No instance HasServer (a -> b). ...Maybe you have used '->' instead of ':>' between ...Capture' '[] "foo" Int ...and ...Verb 'GET 200 '[JSON] Int ...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (a -> b) m :: Type Source # Methods route :: Proxy (a -> b) -> Context context -> Delayed env (Server (a -> b)) -> Router env Source # hoistServerWithContext :: Proxy (a -> b) -> Proxy context -> (forall x. m x -> n x) -> ServerT (a -> b) m -> ServerT (a -> b) n Source #
(HasServer a context, HasServer b context) => HasServer (a :<\|> b :: Type) context Source #	A server for `a :<\|> b` first tries to match the request against the route represented by `a` and if it fails tries `b`. You must provide a request handler for each route. type MyApi = "books" :> Get '[JSON] [Book] -- GET /books :<\|> "books" :> ReqBody Book :> Post '[JSON] Book -- POST /books server :: Server MyApi server = listAllBooks :<\|> postBook where listAllBooks = ... postBook book = ...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (a :<\|> b) m :: Type Source # Methods route :: Proxy (a :<\|> b) -> Context context -> Delayed env (Server (a :<\|> b)) -> Router env Source # hoistServerWithContext :: Proxy (a :<\|> b) -> Proxy context -> (forall x. m x -> n x) -> ServerT (a :<\|> b) m -> ServerT (a :<\|> b) n Source #
(HasContextEntry context (NamedContext name subContext), HasServer subApi subContext) => HasServer (WithNamedContext name subContext subApi :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (WithNamedContext name subContext subApi) m :: Type Source # Methods route :: Proxy (WithNamedContext name subContext subApi) -> Context context -> Delayed env (Server (WithNamedContext name subContext subApi)) -> Router env Source # hoistServerWithContext :: Proxy (WithNamedContext name subContext subApi) -> Proxy context -> (forall x. m x -> n x) -> ServerT (WithNamedContext name subContext subApi) m -> ServerT (WithNamedContext name subContext subApi) n Source #
(TypeError (HasServerArrowKindError arr) :: Constraint) => HasServer (arr :> api :: Type) context Source #	This instance catches mistakes when there are non-saturated type applications on LHS of `:>`. `>>>` `serve (Proxy :: Proxy (Capture "foo" :> Get '[JSON] Int)) (error "...")`... ...Expected something of kind Symbol or , got: k -> l on the LHS of ':>'. ...Maybe you haven't applied enough arguments to ...Capture' '[] "foo" ... `>>>` `undefined :: Server (Capture "foo" :> Get '[JSON] Int)`... ...Expected something of kind Symbol or , got: k -> l on the LHS of ':>'. ...Maybe you haven't applied enough arguments to ...Capture' '[] "foo" ...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (arr :> api) m :: Type Source # Methods route :: Proxy (arr :> api) -> Context context -> Delayed env (Server (arr :> api)) -> Router env Source # hoistServerWithContext :: Proxy (arr :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (arr :> api) m -> ServerT (arr :> api) n Source #
HasServer api context => HasServer (HttpVersion :> api :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (HttpVersion :> api) m :: Type Source # Methods route :: Proxy (HttpVersion :> api) -> Context context -> Delayed env (Server (HttpVersion :> api)) -> Router env Source # hoistServerWithContext :: Proxy (HttpVersion :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (HttpVersion :> api) m -> ServerT (HttpVersion :> api) n Source #
(FramingUnrender framing, FromSourceIO chunk a, MimeUnrender ctype chunk, HasServer api context) => HasServer (StreamBody' mods framing ctype a :> api :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (StreamBody' mods framing ctype a :> api) m :: Type Source # Methods route :: Proxy (StreamBody' mods framing ctype a :> api) -> Context context -> Delayed env (Server (StreamBody' mods framing ctype a :> api)) -> Router env Source # hoistServerWithContext :: Proxy (StreamBody' mods framing ctype a :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (StreamBody' mods framing ctype a :> api) m -> ServerT (StreamBody' mods framing ctype a :> api) n Source #
(AllCTUnrender list a, HasServer api context, SBoolI (FoldLenient mods)) => HasServer (ReqBody' mods list a :> api :: Type) context Source #	If you use `ReqBody` in one of the endpoints for your API, this automatically requires your server-side handler to be a function that takes an argument of the type specified by `ReqBody`. The `Content-Type` header is inspected, and the list provided is used to attempt deserialization. If the request does not have a `Content-Type` header, it is treated as `application/octet-stream` (as specified in RFC7231. This lets servant worry about extracting it from the request and turning it into a value of the type you specify. All it asks is for a `FromJSON` instance. Example: type MyApi = "books" :> ReqBody '[JSON] Book :> Post '[JSON] Book server :: Server MyApi server = postBook where postBook :: Book -> Handler Book postBook book = ...insert into your db...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (ReqBody' mods list a :> api) m :: Type Source # Methods route :: Proxy (ReqBody' mods list a :> api) -> Context context -> Delayed env (Server (ReqBody' mods list a :> api)) -> Router env Source # hoistServerWithContext :: Proxy (ReqBody' mods list a :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (ReqBody' mods list a :> api) m -> ServerT (ReqBody' mods list a :> api) n Source #
HasServer api context => HasServer (RemoteHost :> api :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (RemoteHost :> api) m :: Type Source # Methods route :: Proxy (RemoteHost :> api) -> Context context -> Delayed env (Server (RemoteHost :> api)) -> Router env Source # hoistServerWithContext :: Proxy (RemoteHost :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (RemoteHost :> api) m -> ServerT (RemoteHost :> api) n Source #
(KnownSymbol sym, FromHttpApiData a, HasServer api context, SBoolI (FoldRequired mods), SBoolI (FoldLenient mods)) => HasServer (QueryParam' mods sym a :> api :: Type) context Source #	If you use `QueryParam "author" Text` in one of the endpoints for your API, this automatically requires your server-side handler to be a function that takes an argument of type `Maybe Text`. This lets servant worry about looking it up in the query string and turning it into a value of the type you specify, enclosed in `Maybe`, because it may not be there and servant would then hand you `Nothing`. You can control how it'll be converted from `Text` to your type by simply providing an instance of `FromHttpApiData` for your type. Example: type MyApi = "books" :> QueryParam "author" Text :> Get '[JSON] [Book] server :: Server MyApi server = getBooksBy where getBooksBy :: Maybe Text -> Handler [Book] getBooksBy Nothing = ...return all books... getBooksBy (Just author) = ...return books by the given author...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (QueryParam' mods sym a :> api) m :: Type Source # Methods route :: Proxy (QueryParam' mods sym a :> api) -> Context context -> Delayed env (Server (QueryParam' mods sym a :> api)) -> Router env Source # hoistServerWithContext :: Proxy (QueryParam' mods sym a :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (QueryParam' mods sym a :> api) m -> ServerT (QueryParam' mods sym a :> api) n Source #
(KnownSymbol sym, FromHttpApiData a, HasServer api context) => HasServer (QueryParams sym a :> api :: Type) context Source #	If you use `QueryParams "authors" Text` in one of the endpoints for your API, this automatically requires your server-side handler to be a function that takes an argument of type `[Text]`. This lets servant worry about looking up 0 or more values in the query string associated to `authors` and turning each of them into a value of the type you specify. You can control how the individual values are converted from `Text` to your type by simply providing an instance of `FromHttpApiData` for your type. Example: type MyApi = "books" :> QueryParams "authors" Text :> Get '[JSON] [Book] server :: Server MyApi server = getBooksBy where getBooksBy :: [Text] -> Handler [Book] getBooksBy authors = ...return all books by these authors...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (QueryParams sym a :> api) m :: Type Source # Methods route :: Proxy (QueryParams sym a :> api) -> Context context -> Delayed env (Server (QueryParams sym a :> api)) -> Router env Source # hoistServerWithContext :: Proxy (QueryParams sym a :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (QueryParams sym a :> api) m -> ServerT (QueryParams sym a :> api) n Source #
(KnownSymbol sym, HasServer api context) => HasServer (QueryFlag sym :> api :: Type) context Source #	If you use `QueryFlag "published"` in one of the endpoints for your API, this automatically requires your server-side handler to be a function that takes an argument of type `Bool`. Example: type MyApi = "books" :> QueryFlag "published" :> Get '[JSON] [Book] server :: Server MyApi server = getBooks where getBooks :: Bool -> Handler [Book] getBooks onlyPublished = ...return all books, or only the ones that are already published, depending on the argument...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (QueryFlag sym :> api) m :: Type Source # Methods route :: Proxy (QueryFlag sym :> api) -> Context context -> Delayed env (Server (QueryFlag sym :> api)) -> Router env Source # hoistServerWithContext :: Proxy (QueryFlag sym :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (QueryFlag sym :> api) m -> ServerT (QueryFlag sym :> api) n Source #
(KnownSymbol sym, FromHttpApiData a, HasServer api context, SBoolI (FoldRequired mods), SBoolI (FoldLenient mods)) => HasServer (Header' mods sym a :> api :: Type) context Source #	If you use `Header` in one of the endpoints for your API, this automatically requires your server-side handler to be a function that takes an argument of the type specified by `Header`. This lets servant worry about extracting it from the request and turning it into a value of the type you specify. All it asks is for a `FromHttpApiData` instance. Example: newtype Referer = Referer Text deriving (Eq, Show, FromHttpApiData) -- GET /view-my-referer type MyApi = "view-my-referer" :> Header "Referer" Referer :> Get '[JSON] Referer server :: Server MyApi server = viewReferer where viewReferer :: Referer -> Handler referer viewReferer referer = return referer
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Header' mods sym a :> api) m :: Type Source # Methods route :: Proxy (Header' mods sym a :> api) -> Context context -> Delayed env (Server (Header' mods sym a :> api)) -> Router env Source # hoistServerWithContext :: Proxy (Header' mods sym a :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (Header' mods sym a :> api) m -> ServerT (Header' mods sym a :> api) n Source #
HasServer api context => HasServer (IsSecure :> api :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (IsSecure :> api) m :: Type Source # Methods route :: Proxy (IsSecure :> api) -> Context context -> Delayed env (Server (IsSecure :> api)) -> Router env Source # hoistServerWithContext :: Proxy (IsSecure :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (IsSecure :> api) m -> ServerT (IsSecure :> api) n Source #
(HasServer api context, HasContextEntry context (AuthHandler Request (AuthServerData (AuthProtect tag)))) => HasServer (AuthProtect tag :> api :: Type) context Source #	Known orphan instance.
Instance details Defined in Servant.Server.Experimental.Auth Associated Types type ServerT (AuthProtect tag :> api) m :: Type Source # Methods route :: Proxy (AuthProtect tag :> api) -> Context context -> Delayed env (Server (AuthProtect tag :> api)) -> Router env Source # hoistServerWithContext :: Proxy (AuthProtect tag :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (AuthProtect tag :> api) m -> ServerT (AuthProtect tag :> api) n Source #
HasServer api ctx => HasServer (Summary desc :> api :: Type) ctx Source #	Ignore `Summary` in server handlers.
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Summary desc :> api) m :: Type Source # Methods route :: Proxy (Summary desc :> api) -> Context ctx -> Delayed env (Server (Summary desc :> api)) -> Router env Source # hoistServerWithContext :: Proxy (Summary desc :> api) -> Proxy ctx -> (forall x. m x -> n x) -> ServerT (Summary desc :> api) m -> ServerT (Summary desc :> api) n Source #
HasServer api ctx => HasServer (Description desc :> api :: Type) ctx Source #	Ignore `Description` in server handlers.
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Description desc :> api) m :: Type Source # Methods route :: Proxy (Description desc :> api) -> Context ctx -> Delayed env (Server (Description desc :> api)) -> Router env Source # hoistServerWithContext :: Proxy (Description desc :> api) -> Proxy ctx -> (forall x. m x -> n x) -> ServerT (Description desc :> api) m -> ServerT (Description desc :> api) n Source #
(KnownSymbol capture, FromHttpApiData a, HasServer api context) => HasServer (Capture' mods capture a :> api :: Type) context Source #	If you use `Capture` in one of the endpoints for your API, this automatically requires your server-side handler to be a function that takes an argument of the type specified by the `Capture`. This lets servant worry about getting it from the URL and turning it into a value of the type you specify. You can control how it'll be converted from `Text` to your type by simply providing an instance of `FromHttpApiData` for your type. Example: type MyApi = "books" :> Capture "isbn" Text :> Get '[JSON] Book server :: Server MyApi server = getBook where getBook :: Text -> Handler Book getBook isbn = ...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Capture' mods capture a :> api) m :: Type Source # Methods route :: Proxy (Capture' mods capture a :> api) -> Context context -> Delayed env (Server (Capture' mods capture a :> api)) -> Router env Source # hoistServerWithContext :: Proxy (Capture' mods capture a :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (Capture' mods capture a :> api) m -> ServerT (Capture' mods capture a :> api) n Source #
(KnownSymbol capture, FromHttpApiData a, HasServer api context) => HasServer (CaptureAll capture a :> api :: Type) context Source #	If you use `CaptureAll` in one of the endpoints for your API, this automatically requires your server-side handler to be a function that takes an argument of a list of the type specified by the `CaptureAll`. This lets servant worry about getting values from the URL and turning them into values of the type you specify. You can control how they'll be converted from `Text` to your type by simply providing an instance of `FromHttpApiData` for your type. Example: type MyApi = "src" :> CaptureAll "segments" Text :> Get '[JSON] SourceFile server :: Server MyApi server = getSourceFile where getSourceFile :: [Text] -> Handler Book getSourceFile pathSegments = ...
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (CaptureAll capture a :> api) m :: Type Source # Methods route :: Proxy (CaptureAll capture a :> api) -> Context context -> Delayed env (Server (CaptureAll capture a :> api)) -> Router env Source # hoistServerWithContext :: Proxy (CaptureAll capture a :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (CaptureAll capture a :> api) m -> ServerT (CaptureAll capture a :> api) n Source #
(KnownSymbol realm, HasServer api context, HasContextEntry context (BasicAuthCheck usr)) => HasServer (BasicAuth realm usr :> api :: Type) context Source #	Basic Authentication
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (BasicAuth realm usr :> api) m :: Type Source # Methods route :: Proxy (BasicAuth realm usr :> api) -> Context context -> Delayed env (Server (BasicAuth realm usr :> api)) -> Router env Source # hoistServerWithContext :: Proxy (BasicAuth realm usr :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (BasicAuth realm usr :> api) m -> ServerT (BasicAuth realm usr :> api) n Source #
HasServer api context => HasServer (Vault :> api :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Vault :> api) m :: Type Source # Methods route :: Proxy (Vault :> api) -> Context context -> Delayed env (Server (Vault :> api)) -> Router env Source # hoistServerWithContext :: Proxy (Vault :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (Vault :> api) m -> ServerT (Vault :> api) n Source #
(KnownSymbol path, HasServer api context) => HasServer (path :> api :: Type) context Source #	Make sure the incoming request starts with `"/path"`, strip it and pass the rest of the request path to `api`.
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (path :> api) m :: Type Source # Methods route :: Proxy (path :> api) -> Context context -> Delayed env (Server (path :> api)) -> Router env Source # hoistServerWithContext :: Proxy (path :> api) -> Proxy context -> (forall x. m x -> n x) -> ServerT (path :> api) m -> ServerT (path :> api) n Source #
(AllCTRender ctypes a, ReflectMethod method, KnownNat status, GetHeaders (Headers h a)) => HasServer (Verb method status ctypes (Headers h a) :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Verb method status ctypes (Headers h a)) m :: Type Source # Methods route :: Proxy (Verb method status ctypes (Headers h a)) -> Context context -> Delayed env (Server (Verb method status ctypes (Headers h a))) -> Router env Source # hoistServerWithContext :: Proxy (Verb method status ctypes (Headers h a)) -> Proxy context -> (forall x. m x -> n x) -> ServerT (Verb method status ctypes (Headers h a)) m -> ServerT (Verb method status ctypes (Headers h a)) n Source #
(AllCTRender ctypes a, ReflectMethod method, KnownNat status) => HasServer (Verb method status ctypes a :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Verb method status ctypes a) m :: Type Source # Methods route :: Proxy (Verb method status ctypes a) -> Context context -> Delayed env (Server (Verb method status ctypes a)) -> Router env Source # hoistServerWithContext :: Proxy (Verb method status ctypes a) -> Proxy context -> (forall x. m x -> n x) -> ServerT (Verb method status ctypes a) m -> ServerT (Verb method status ctypes a) n Source #
(MimeRender ctype chunk, ReflectMethod method, KnownNat status, FramingRender framing, ToSourceIO chunk a, GetHeaders (Headers h a)) => HasServer (Stream method status framing ctype (Headers h a) :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Stream method status framing ctype (Headers h a)) m :: Type Source # Methods route :: Proxy (Stream method status framing ctype (Headers h a)) -> Context context -> Delayed env (Server (Stream method status framing ctype (Headers h a))) -> Router env Source # hoistServerWithContext :: Proxy (Stream method status framing ctype (Headers h a)) -> Proxy context -> (forall x. m x -> n x) -> ServerT (Stream method status framing ctype (Headers h a)) m -> ServerT (Stream method status framing ctype (Headers h a)) n Source #
(MimeRender ctype chunk, ReflectMethod method, KnownNat status, FramingRender framing, ToSourceIO chunk a) => HasServer (Stream method status framing ctype a :: Type) context Source #
Instance details Defined in Servant.Server.Internal Associated Types type ServerT (Stream method status framing ctype a) m :: Type Source # Methods route :: Proxy (Stream method status framing ctype a) -> Context context -> Delayed env (Server (Stream method status framing ctype a)) -> Router env Source # hoistServerWithContext :: Proxy (Stream method status framing ctype a) -> Proxy context -> (forall x. m x -> n x) -> ServerT (Stream method status framing ctype a) m -> ServerT (Stream method status framing ctype a) n Source #

type Server api = ServerT api Handler Source #

data EmptyServer Source #

Singleton type representing a server that serves an empty API.

Instances

Bounded EmptyServer Source #
Instance details Defined in Servant.Server.Internal Methods minBound :: EmptyServer # maxBound :: EmptyServer #
Enum EmptyServer Source #
Instance details Defined in Servant.Server.Internal Methods succ :: EmptyServer -> EmptyServer # pred :: EmptyServer -> EmptyServer # toEnum :: Int -> EmptyServer # fromEnum :: EmptyServer -> Int # enumFrom :: EmptyServer -> [EmptyServer] # enumFromThen :: EmptyServer -> EmptyServer -> [EmptyServer] # enumFromTo :: EmptyServer -> EmptyServer -> [EmptyServer] # enumFromThenTo :: EmptyServer -> EmptyServer -> EmptyServer -> [EmptyServer] #
Eq EmptyServer Source #
Instance details Defined in Servant.Server.Internal Methods (==) :: EmptyServer -> EmptyServer -> Bool # (/=) :: EmptyServer -> EmptyServer -> Bool #
Show EmptyServer Source #
Instance details Defined in Servant.Server.Internal Methods showsPrec :: Int -> EmptyServer -> ShowS # show :: EmptyServer -> String # showList :: [EmptyServer] -> ShowS #

emptyServer :: ServerT EmptyAPI m Source #

Server for EmptyAPI

newtype Handler a Source #

Constructors

Handler
Fields runHandler' :: ExceptT ServantErr IO a

Instances

Monad Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods (>>=) :: Handler a -> (a -> Handler b) -> Handler b # (>>) :: Handler a -> Handler b -> Handler b # return :: a -> Handler a # fail :: String -> Handler a #
Functor Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods fmap :: (a -> b) -> Handler a -> Handler b # (<$) :: a -> Handler b -> Handler a #
Applicative Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods pure :: a -> Handler a # (<>) :: Handler (a -> b) -> Handler a -> Handler b # liftA2 :: (a -> b -> c) -> Handler a -> Handler b -> Handler c # (>) :: Handler a -> Handler b -> Handler b # (<*) :: Handler a -> Handler b -> Handler a #
MonadIO Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods liftIO :: IO a -> Handler a #
MonadThrow Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods throwM :: Exception e => e -> Handler a #
MonadCatch Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods catch :: Exception e => Handler a -> (e -> Handler a) -> Handler a #
MonadMask Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods mask :: ((forall a. Handler a -> Handler a) -> Handler b) -> Handler b # uninterruptibleMask :: ((forall a. Handler a -> Handler a) -> Handler b) -> Handler b # generalBracket :: Handler a -> (a -> ExitCase b -> Handler c) -> (a -> Handler b) -> Handler (b, c) #
MonadBase IO Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods liftBase :: IO α -> Handler α #
MonadBaseControl IO Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Associated Types type StM Handler a :: Type # Methods liftBaseWith :: (RunInBase Handler IO -> IO a) -> Handler a # restoreM :: StM Handler a -> Handler a #
MonadError ServantErr Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods throwError :: ServantErr -> Handler a # catchError :: Handler a -> (ServantErr -> Handler a) -> Handler a #
Generic (Handler a) Source #
Instance details Defined in Servant.Server.Internal.Handler Associated Types type Rep (Handler a) :: Type -> Type # Methods from :: Handler a -> Rep (Handler a) x # to :: Rep (Handler a) x -> Handler a #
type StM Handler a Source #
Instance details Defined in Servant.Server.Internal.Handler type StM Handler a = Either ServantErr a
type Rep (Handler a) Source #
Instance details Defined in Servant.Server.Internal.Handler type Rep (Handler a) = D1 (MetaData "Handler" "Servant.Server.Internal.Handler" "servant-server-0.15-HZ8jkJtk2sLGoQdbJQiUb3" True) (C1 (MetaCons "Handler" PrefixI True) (S1 (MetaSel (Just "runHandler'") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (ExceptT ServantErr IO a))))

runHandler :: Handler a -> IO (Either ServantErr a) Source #

Debugging the server layout

layout :: HasServer api '[] => Proxy api -> Text Source #

The function layout produces a textual description of the internal router layout for debugging purposes. Note that the router layout is determined just by the API, not by the handlers.

Example:

For the following API

type API =
       "a" :> "d" :> Get '[JSON] NoContent
  :<|> "b" :> Capture "x" Int :> Get '[JSON] Bool
  :<|> "c" :> Put '[JSON] Bool
  :<|> "a" :> "e" :> Get '[JSON] Int
  :<|> "b" :> Capture "x" Int :> Put '[JSON] Bool
  :<|> Raw

we get the following output:

/
├─ a/
│  ├─ d/
│  │  └─•
│  └─ e/
│     └─•
├─ b/
│  └─ <capture>/
│     ├─•
│     ┆
│     └─•
├─ c/
│  └─•
┆
└─ <raw>

Explanation of symbols:

├: Normal lines reflect static branching via a table.
a/: Nodes reflect static path components.
─•: Leaves reflect endpoints.
<capture>/: This is a delayed capture of a path component.
<raw>: This is a part of the API we do not know anything about.
┆: Dashed lines suggest a dynamic choice between the part above and below. If there is a success for fatal failure in the first part, that one takes precedence. If both parts fail, the "better" error code will be returned.

layoutWithContext :: HasServer api context => Proxy api -> Context context -> Text Source #

Variant of layout that takes an additional Context.

Enter / hoisting server

hoistServer :: HasServer api '[] => Proxy api -> (forall x. m x -> n x) -> ServerT api m -> ServerT api n Source #

Hoist server implementation.

Sometimes our cherished Handler monad isn't quite the type you'd like for your handlers. Maybe you want to thread some configuration in a Reader monad. Or have your types ensure that your handlers don't do any IO. Use hoistServer (a successor of now deprecated enter).

With hoistServer, you can provide a function, to convert any number of endpoints from one type constructor to another. For example

Note: Server Raw can also be entered. It will be retagged.

>>> import Control.Monad.Reader
>>> type ReaderAPI = "ep1" :> Get '[JSON] Int :<|> "ep2" :> Get '[JSON] String :<|> Raw :<|> EmptyAPI
>>> let readerApi = Proxy :: Proxy ReaderAPI
>>> let readerServer = return 1797 :<|> ask :<|> Tagged (error "raw server") :<|> emptyServer :: ServerT ReaderAPI (Reader String)
>>> let nt x = return (runReader x "hi")
>>> let mainServer = hoistServer readerApi nt readerServer :: Server ReaderAPI

Functions based on mmorph

tweakResponse :: (RouteResult Response -> RouteResult Response) -> Router env -> Router env Source #

Apply a transformation to the response of a Router.

Context

data Context contextTypes where Source #

Contexts are used to pass values to combinators. (They are not meant to be used to pass parameters to your handlers, i.e. they should not replace any custom ReaderT-monad-stack that you're using with hoistServer.) If you don't use combinators that require any context entries, you can just use serve as always.

If you are using combinators that require a non-empty Context you have to use serveWithContext and pass it a Context that contains all the values your combinators need. A Context is essentially a heterogenous list and accessing the elements is being done by type (see getContextEntry). The parameter of the type Context is a type-level list reflecting the types of the contained context entries. To create a Context with entries, use the operator (:.):

>>> :type True :. () :. EmptyContext
True :. () :. EmptyContext :: Context '[Bool, ()]

Constructors

EmptyContext :: Context '[]
(:.) :: x -> Context xs -> Context (x ': xs) infixr 5

Instances

(Eq a, Eq (Context as)) => Eq (Context (a ': as)) Source #
Instance details Defined in Servant.Server.Internal.Context Methods (==) :: Context (a ': as) -> Context (a ': as) -> Bool # (/=) :: Context (a ': as) -> Context (a ': as) -> Bool #
Eq (Context ([] :: [Type])) Source #
Instance details Defined in Servant.Server.Internal.Context Methods (==) :: Context [] -> Context [] -> Bool # (/=) :: Context [] -> Context [] -> Bool #
(Show a, Show (Context as)) => Show (Context (a ': as)) Source #
Instance details Defined in Servant.Server.Internal.Context Methods showsPrec :: Int -> Context (a ': as) -> ShowS # show :: Context (a ': as) -> String # showList :: [Context (a ': as)] -> ShowS #
Show (Context ([] :: [Type])) Source #
Instance details Defined in Servant.Server.Internal.Context Methods showsPrec :: Int -> Context [] -> ShowS # show :: Context [] -> String # showList :: [Context []] -> ShowS #

class HasContextEntry (context :: [*]) (val :: *) where Source #

This class is used to access context entries in Contexts. getContextEntry returns the first value where the type matches:

>>> getContextEntry (True :. False :. EmptyContext) :: Bool
True

If the Context does not contain an entry of the requested type, you'll get an error:

>>> getContextEntry (True :. False :. EmptyContext) :: String
...
...No instance for (HasContextEntry '[] [Char])
...

Methods

getContextEntry :: Context context -> val Source #

Instances

HasContextEntry (val ': xs) val Source #
Instance details Defined in Servant.Server.Internal.Context Methods getContextEntry :: Context (val ': xs) -> val Source #
HasContextEntry xs val => HasContextEntry (notIt ': xs) val Source #
Instance details Defined in Servant.Server.Internal.Context Methods getContextEntry :: Context (notIt ': xs) -> val Source #

NamedContext

data NamedContext (name :: Symbol) (subContext :: [*]) Source #

Normally context entries are accessed by their types. In case you need to have multiple values of the same type in your Context and need to access them, we provide NamedContext. You can think of it as sub-namespaces for Contexts.

Constructors

NamedContext (Context subContext)

descendIntoNamedContext :: forall context name subContext. HasContextEntry context (NamedContext name subContext) => Proxy (name :: Symbol) -> Context context -> Context subContext Source #

descendIntoNamedContext allows you to access NamedContexts. Usually you won't have to use it yourself but instead use a combinator like WithNamedContext.

This is how descendIntoNamedContext works:

>>> :set -XFlexibleContexts
>>> let subContext = True :. EmptyContext
>>> :type subContext
subContext :: Context '[Bool]
>>> let parentContext = False :. (NamedContext subContext :: NamedContext "subContext" '[Bool]) :. EmptyContext
>>> :type parentContext
parentContext :: Context '[Bool, NamedContext "subContext" '[Bool]]
>>> descendIntoNamedContext (Proxy :: Proxy "subContext") parentContext :: Context '[Bool]
True :. EmptyContext

Basic Authentication

newtype BasicAuthCheck usr Source #

Datatype wrapping a function used to check authentication.

Constructors

BasicAuthCheck
Fields unBasicAuthCheck :: BasicAuthData -> IO (BasicAuthResult usr)

Instances

Functor BasicAuthCheck Source #
Instance details Defined in Servant.Server.Internal.BasicAuth Methods fmap :: (a -> b) -> BasicAuthCheck a -> BasicAuthCheck b # (<$) :: a -> BasicAuthCheck b -> BasicAuthCheck a #
Generic (BasicAuthCheck usr) Source #
Instance details Defined in Servant.Server.Internal.BasicAuth Associated Types type Rep (BasicAuthCheck usr) :: Type -> Type # Methods from :: BasicAuthCheck usr -> Rep (BasicAuthCheck usr) x # to :: Rep (BasicAuthCheck usr) x -> BasicAuthCheck usr #
type Rep (BasicAuthCheck usr) Source #
Instance details Defined in Servant.Server.Internal.BasicAuth type Rep (BasicAuthCheck usr) = D1 (MetaData "BasicAuthCheck" "Servant.Server.Internal.BasicAuth" "servant-server-0.15-HZ8jkJtk2sLGoQdbJQiUb3" True) (C1 (MetaCons "BasicAuthCheck" PrefixI True) (S1 (MetaSel (Just "unBasicAuthCheck") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 (BasicAuthData -> IO (BasicAuthResult usr)))))

data BasicAuthResult usr Source #

servant-server's current implementation of basic authentication is not immune to certian kinds of timing attacks. Decoding payloads does not take a fixed amount of time.

The result of authentication/authorization

Constructors

Unauthorized
BadPassword
NoSuchUser
Authorized usr

Instances

Functor BasicAuthResult Source #
Instance details Defined in Servant.Server.Internal.BasicAuth Methods fmap :: (a -> b) -> BasicAuthResult a -> BasicAuthResult b # (<$) :: a -> BasicAuthResult b -> BasicAuthResult a #
Eq usr => Eq (BasicAuthResult usr) Source #
Instance details Defined in Servant.Server.Internal.BasicAuth Methods (==) :: BasicAuthResult usr -> BasicAuthResult usr -> Bool # (/=) :: BasicAuthResult usr -> BasicAuthResult usr -> Bool #
Read usr => Read (BasicAuthResult usr) Source #
Instance details Defined in Servant.Server.Internal.BasicAuth Methods readsPrec :: Int -> ReadS (BasicAuthResult usr) # readList :: ReadS [BasicAuthResult usr] # readPrec :: ReadPrec (BasicAuthResult usr) # readListPrec :: ReadPrec [BasicAuthResult usr] #
Show usr => Show (BasicAuthResult usr) Source #
Instance details Defined in Servant.Server.Internal.BasicAuth Methods showsPrec :: Int -> BasicAuthResult usr -> ShowS # show :: BasicAuthResult usr -> String # showList :: [BasicAuthResult usr] -> ShowS #
Generic (BasicAuthResult usr) Source #
Instance details Defined in Servant.Server.Internal.BasicAuth Associated Types type Rep (BasicAuthResult usr) :: Type -> Type # Methods from :: BasicAuthResult usr -> Rep (BasicAuthResult usr) x # to :: Rep (BasicAuthResult usr) x -> BasicAuthResult usr #
type Rep (BasicAuthResult usr) Source #
Instance details Defined in Servant.Server.Internal.BasicAuth type Rep (BasicAuthResult usr) = D1 (MetaData "BasicAuthResult" "Servant.Server.Internal.BasicAuth" "servant-server-0.15-HZ8jkJtk2sLGoQdbJQiUb3" False) ((C1 (MetaCons "Unauthorized" PrefixI False) (U1 :: Type -> Type) :+: C1 (MetaCons "BadPassword" PrefixI False) (U1 :: Type -> Type)) :+: (C1 (MetaCons "NoSuchUser" PrefixI False) (U1 :: Type -> Type) :+: C1 (MetaCons "Authorized" PrefixI False) (S1 (MetaSel (Nothing :: Maybe Symbol) NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 usr))))

General Authentication

Default error type

data ServantErr Source #

Constructors

ServantErr
Fields errHTTPCode :: Int errReasonPhrase :: String errBody :: ByteString errHeaders :: [Header]

Instances

Eq ServantErr Source #
Instance details Defined in Servant.Server.Internal.ServantErr Methods (==) :: ServantErr -> ServantErr -> Bool # (/=) :: ServantErr -> ServantErr -> Bool #
Read ServantErr Source #
Instance details Defined in Servant.Server.Internal.ServantErr Methods readsPrec :: Int -> ReadS ServantErr # readList :: ReadS [ServantErr] # readPrec :: ReadPrec ServantErr # readListPrec :: ReadPrec [ServantErr] #
Show ServantErr Source #
Instance details Defined in Servant.Server.Internal.ServantErr Methods showsPrec :: Int -> ServantErr -> ShowS # show :: ServantErr -> String # showList :: [ServantErr] -> ShowS #
Exception ServantErr Source #
Instance details Defined in Servant.Server.Internal.ServantErr Methods toException :: ServantErr -> SomeException # fromException :: SomeException -> Maybe ServantErr # displayException :: ServantErr -> String #
MonadError ServantErr Handler Source #
Instance details Defined in Servant.Server.Internal.Handler Methods throwError :: ServantErr -> Handler a # catchError :: Handler a -> (ServantErr -> Handler a) -> Handler a #

3XX

err300 :: ServantErr Source #

err300 Multiple Choices

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err300 { errBody = "I can't choose." }

err301 :: ServantErr Source #

err301 Moved Permanently

Example:

failingHandler :: Handler ()
failingHandler = throwError err301

err302 :: ServantErr Source #

err302 Found

Example:

failingHandler :: Handler ()
failingHandler = throwError err302

err303 :: ServantErr Source #

err303 See Other

Example:

failingHandler :: Handler ()
failingHandler = throwError err303

err304 :: ServantErr Source #

err304 Not Modified

Example:

failingHandler :: Handler ()
failingHandler = throwError err304

err305 :: ServantErr Source #

err305 Use Proxy

Example:

failingHandler :: Handler ()
failingHandler = throwError err305

err307 :: ServantErr Source #

err307 Temporary Redirect

Example:

failingHandler :: Handler ()
failingHandler = throwError err307

4XX

err400 :: ServantErr Source #

err400 Bad Request

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err400 { errBody = "Your request makes no sense to me." }

err401 :: ServantErr Source #

err401 Unauthorized

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err401 { errBody = "Your credentials are invalid." }

err402 :: ServantErr Source #

err402 Payment Required

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err402 { errBody = "You have 0 credits. Please give me $$$." }

err403 :: ServantErr Source #

err403 Forbidden

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err403 { errBody = "Please login first." }

err404 :: ServantErr Source #

err404 Not Found

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err404 { errBody = "(╯°□°）╯︵ ┻━┻)." }

err405 :: ServantErr Source #

err405 Method Not Allowed

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err405 { errBody = "Your account privileges does not allow for this.  Please pay $$$." }

err406 :: ServantErr Source #

err406 Not Acceptable

Example:

failingHandler :: Handler ()
failingHandler = throwError err406

err407 :: ServantErr Source #

err407 Proxy Authentication Required

Example:

failingHandler :: Handler ()
failingHandler = throwError err407

err409 :: ServantErr Source #

err409 Conflict

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err409 { errBody = "Transaction conflicts with 59879cb56c7c159231eeacdd503d755f7e835f74" }

err410 :: ServantErr Source #

err410 Gone

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err410 { errBody = "I know it was here at some point, but.. I blame bad luck." }

err411 :: ServantErr Source #

err411 Length Required

Example:

failingHandler :: Handler ()
failingHandler = throwError err411

err412 :: ServantErr Source #

err412 Precondition Failed

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err412 { errBody = "Precondition fail: x < 42 && y > 57" }

err413 :: ServantErr Source #

err413 Request Entity Too Large

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err413 { errBody = "Request exceeded 64k." }

err414 :: ServantErr Source #

err414 Request-URI Too Large

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err414 { errBody = "Maximum length is 64." }

err415 :: ServantErr Source #

err415 Unsupported Media Type

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err415 { errBody = "Supported media types:  gif, png" }

err416 :: ServantErr Source #

err416 Request range not satisfiable

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err416 { errBody = "Valid range is [0, 424242]." }

err417 :: ServantErr Source #

err417 Expectation Failed

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err417 { errBody = "I found a quux in the request.  This isn't going to work." }

err418 :: ServantErr Source #

err418 Expectation Failed

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err418 { errBody = "Apologies, this is not a webserver but a teapot." }

err422 :: ServantErr Source #

err422 Unprocessable Entity

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err422 { errBody = "I understood your request, but can't process it." }

5XX

err500 :: ServantErr Source #

err500 Internal Server Error

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err500 { errBody = "Exception in module A.B.C:55.  Have a great day!" }

err501 :: ServantErr Source #

err501 Not Implemented

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err501 { errBody = "/v1/foo is not supported with quux in the request." }

err502 :: ServantErr Source #

err502 Bad Gateway

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err502 { errBody = "Tried gateway foo, bar, and baz.  None responded." }

err503 :: ServantErr Source #

err503 Service Unavailable

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err503 { errBody = "We're rewriting in PHP." }

err504 :: ServantErr Source #

err504 Gateway Time-out

Example:

failingHandler :: Handler ()
failingHandler = throwError $ err504 { errBody = "Backend foobar did not respond in 5 seconds." }

err505 :: ServantErr Source #

err505 HTTP Version not supported

Example usage:

failingHandler :: Handler ()
failingHandler = throwError $ err505 { errBody = "I support HTTP/4.0 only." }

Re-exports

type Application = Request -> (Response -> IO ResponseReceived) -> IO ResponseReceived #

The WAI application.

Note that, since WAI 3.0, this type is structured in continuation passing style to allow for proper safe resource handling. This was handled in the past via other means (e.g., ResourceT). As a demonstration:

app :: Application
app req respond = bracket_
    (putStrLn "Allocating scarce resource")
    (putStrLn "Cleaning up")
    (respond $ responseLBS status200 [] "Hello World")

newtype Tagged (s :: k) b :: forall k. k -> Type -> Type #

A Tagged s b value is a value b with an attached phantom type s. This can be used in place of the more traditional but less safe idiom of passing in an undefined value with the type, because unlike an (s -> b), a Tagged s b can't try to use the argument s as a real value.

Moreover, you don't have to rely on the compiler to inline away the extra argument, because the newtype is "free"

Tagged has kind k -> * -> * if the compiler supports PolyKinds, therefore there is an extra k showing in the instance haddocks that may cause confusion.

Constructors

Tagged
Fields unTagged :: b

Instances

Bitraversable (Tagged :: Type -> Type -> Type)
Instance details Defined in Data.Tagged Methods bitraverse :: Applicative f => (a -> f c) -> (b -> f d) -> Tagged a b -> f (Tagged c d) #
Bifoldable (Tagged :: Type -> Type -> Type)
Instance details Defined in Data.Tagged Methods bifold :: Monoid m => Tagged m m -> m # bifoldMap :: Monoid m => (a -> m) -> (b -> m) -> Tagged a b -> m # bifoldr :: (a -> c -> c) -> (b -> c -> c) -> c -> Tagged a b -> c # bifoldl :: (c -> a -> c) -> (c -> b -> c) -> c -> Tagged a b -> c #
Bifunctor (Tagged :: Type -> Type -> Type)
Instance details Defined in Data.Tagged Methods bimap :: (a -> b) -> (c -> d) -> Tagged a c -> Tagged b d # first :: (a -> b) -> Tagged a c -> Tagged b c # second :: (b -> c) -> Tagged a b -> Tagged a c #
Eq2 (Tagged :: Type -> Type -> Type)
Instance details Defined in Data.Tagged Methods liftEq2 :: (a -> b -> Bool) -> (c -> d -> Bool) -> Tagged a c -> Tagged b d -> Bool #
Ord2 (Tagged :: Type -> Type -> Type)
Instance details Defined in Data.Tagged Methods liftCompare2 :: (a -> b -> Ordering) -> (c -> d -> Ordering) -> Tagged a c -> Tagged b d -> Ordering #
Read2 (Tagged :: Type -> Type -> Type)
Instance details Defined in Data.Tagged Methods liftReadsPrec2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> Int -> ReadS (Tagged a b) # liftReadList2 :: (Int -> ReadS a) -> ReadS [a] -> (Int -> ReadS b) -> ReadS [b] -> ReadS [Tagged a b] # liftReadPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec (Tagged a b) # liftReadListPrec2 :: ReadPrec a -> ReadPrec [a] -> ReadPrec b -> ReadPrec [b] -> ReadPrec [Tagged a b] #
Show2 (Tagged :: Type -> Type -> Type)
Instance details Defined in Data.Tagged Methods liftShowsPrec2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> Int -> Tagged a b -> ShowS # liftShowList2 :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> (Int -> b -> ShowS) -> ([b] -> ShowS) -> [Tagged a b] -> ShowS #
Generic1 (Tagged s :: Type -> Type)
Instance details Defined in Data.Tagged Associated Types type Rep1 (Tagged s) :: k -> Type # Methods from1 :: Tagged s a -> Rep1 (Tagged s) a # to1 :: Rep1 (Tagged s) a -> Tagged s a #
Monad (Tagged s)
Instance details Defined in Data.Tagged Methods (>>=) :: Tagged s a -> (a -> Tagged s b) -> Tagged s b # (>>) :: Tagged s a -> Tagged s b -> Tagged s b # return :: a -> Tagged s a # fail :: String -> Tagged s a #
Functor (Tagged s)
Instance details Defined in Data.Tagged Methods fmap :: (a -> b) -> Tagged s a -> Tagged s b # (<$) :: a -> Tagged s b -> Tagged s a #
Applicative (Tagged s)
Instance details Defined in Data.Tagged Methods pure :: a -> Tagged s a # (<>) :: Tagged s (a -> b) -> Tagged s a -> Tagged s b # liftA2 :: (a -> b -> c) -> Tagged s a -> Tagged s b -> Tagged s c # (>) :: Tagged s a -> Tagged s b -> Tagged s b # (<*) :: Tagged s a -> Tagged s b -> Tagged s a #
Foldable (Tagged s)
Instance details Defined in Data.Tagged Methods fold :: Monoid m => Tagged s m -> m # foldMap :: Monoid m => (a -> m) -> Tagged s a -> m # foldr :: (a -> b -> b) -> b -> Tagged s a -> b # foldr' :: (a -> b -> b) -> b -> Tagged s a -> b # foldl :: (b -> a -> b) -> b -> Tagged s a -> b # foldl' :: (b -> a -> b) -> b -> Tagged s a -> b # foldr1 :: (a -> a -> a) -> Tagged s a -> a # foldl1 :: (a -> a -> a) -> Tagged s a -> a # toList :: Tagged s a -> [a] # null :: Tagged s a -> Bool # length :: Tagged s a -> Int # elem :: Eq a => a -> Tagged s a -> Bool # maximum :: Ord a => Tagged s a -> a # minimum :: Ord a => Tagged s a -> a # sum :: Num a => Tagged s a -> a # product :: Num a => Tagged s a -> a #
Traversable (Tagged s)
Instance details Defined in Data.Tagged Methods traverse :: Applicative f => (a -> f b) -> Tagged s a -> f (Tagged s b) # sequenceA :: Applicative f => Tagged s (f a) -> f (Tagged s a) # mapM :: Monad m => (a -> m b) -> Tagged s a -> m (Tagged s b) # sequence :: Monad m => Tagged s (m a) -> m (Tagged s a) #
Eq1 (Tagged s)
Instance details Defined in Data.Tagged Methods liftEq :: (a -> b -> Bool) -> Tagged s a -> Tagged s b -> Bool #
Ord1 (Tagged s)
Instance details Defined in Data.Tagged Methods liftCompare :: (a -> b -> Ordering) -> Tagged s a -> Tagged s b -> Ordering #
Read1 (Tagged s)
Instance details Defined in Data.Tagged Methods liftReadsPrec :: (Int -> ReadS a) -> ReadS [a] -> Int -> ReadS (Tagged s a) # liftReadList :: (Int -> ReadS a) -> ReadS [a] -> ReadS [Tagged s a] # liftReadPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec (Tagged s a) # liftReadListPrec :: ReadPrec a -> ReadPrec [a] -> ReadPrec [Tagged s a] #
Show1 (Tagged s)
Instance details Defined in Data.Tagged Methods liftShowsPrec :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> Int -> Tagged s a -> ShowS # liftShowList :: (Int -> a -> ShowS) -> ([a] -> ShowS) -> [Tagged s a] -> ShowS #
Bounded b => Bounded (Tagged s b)
Instance details Defined in Data.Tagged Methods minBound :: Tagged s b # maxBound :: Tagged s b #
Enum a => Enum (Tagged s a)
Instance details Defined in Data.Tagged Methods succ :: Tagged s a -> Tagged s a # pred :: Tagged s a -> Tagged s a # toEnum :: Int -> Tagged s a # fromEnum :: Tagged s a -> Int # enumFrom :: Tagged s a -> [Tagged s a] # enumFromThen :: Tagged s a -> Tagged s a -> [Tagged s a] # enumFromTo :: Tagged s a -> Tagged s a -> [Tagged s a] # enumFromThenTo :: Tagged s a -> Tagged s a -> Tagged s a -> [Tagged s a] #
Eq b => Eq (Tagged s b)
Instance details Defined in Data.Tagged Methods (==) :: Tagged s b -> Tagged s b -> Bool # (/=) :: Tagged s b -> Tagged s b -> Bool #
Floating a => Floating (Tagged s a)
Instance details Defined in Data.Tagged Methods pi :: Tagged s a # exp :: Tagged s a -> Tagged s a # log :: Tagged s a -> Tagged s a # sqrt :: Tagged s a -> Tagged s a # (**) :: Tagged s a -> Tagged s a -> Tagged s a # logBase :: Tagged s a -> Tagged s a -> Tagged s a # sin :: Tagged s a -> Tagged s a # cos :: Tagged s a -> Tagged s a # tan :: Tagged s a -> Tagged s a # asin :: Tagged s a -> Tagged s a # acos :: Tagged s a -> Tagged s a # atan :: Tagged s a -> Tagged s a # sinh :: Tagged s a -> Tagged s a # cosh :: Tagged s a -> Tagged s a # tanh :: Tagged s a -> Tagged s a # asinh :: Tagged s a -> Tagged s a # acosh :: Tagged s a -> Tagged s a # atanh :: Tagged s a -> Tagged s a # log1p :: Tagged s a -> Tagged s a # expm1 :: Tagged s a -> Tagged s a # log1pexp :: Tagged s a -> Tagged s a # log1mexp :: Tagged s a -> Tagged s a #
Fractional a => Fractional (Tagged s a)
Instance details Defined in Data.Tagged Methods (/) :: Tagged s a -> Tagged s a -> Tagged s a # recip :: Tagged s a -> Tagged s a # fromRational :: Rational -> Tagged s a #
Integral a => Integral (Tagged s a)
Instance details Defined in Data.Tagged Methods quot :: Tagged s a -> Tagged s a -> Tagged s a # rem :: Tagged s a -> Tagged s a -> Tagged s a # div :: Tagged s a -> Tagged s a -> Tagged s a # mod :: Tagged s a -> Tagged s a -> Tagged s a # quotRem :: Tagged s a -> Tagged s a -> (Tagged s a, Tagged s a) # divMod :: Tagged s a -> Tagged s a -> (Tagged s a, Tagged s a) # toInteger :: Tagged s a -> Integer #
(Data s, Data b) => Data (Tagged s b)
Instance details Defined in Data.Tagged Methods gfoldl :: (forall d b0. Data d => c (d -> b0) -> d -> c b0) -> (forall g. g -> c g) -> Tagged s b -> c (Tagged s b) # gunfold :: (forall b0 r. Data b0 => c (b0 -> r) -> c r) -> (forall r. r -> c r) -> Constr -> c (Tagged s b) # toConstr :: Tagged s b -> Constr # dataTypeOf :: Tagged s b -> DataType # dataCast1 :: Typeable t => (forall d. Data d => c (t d)) -> Maybe (c (Tagged s b)) # dataCast2 :: Typeable t => (forall d e. (Data d, Data e) => c (t d e)) -> Maybe (c (Tagged s b)) # gmapT :: (forall b0. Data b0 => b0 -> b0) -> Tagged s b -> Tagged s b # gmapQl :: (r -> r' -> r) -> r -> (forall d. Data d => d -> r') -> Tagged s b -> r # gmapQr :: (r' -> r -> r) -> r -> (forall d. Data d => d -> r') -> Tagged s b -> r # gmapQ :: (forall d. Data d => d -> u) -> Tagged s b -> [u] # gmapQi :: Int -> (forall d. Data d => d -> u) -> Tagged s b -> u # gmapM :: Monad m => (forall d. Data d => d -> m d) -> Tagged s b -> m (Tagged s b) # gmapMp :: MonadPlus m => (forall d. Data d => d -> m d) -> Tagged s b -> m (Tagged s b) # gmapMo :: MonadPlus m => (forall d. Data d => d -> m d) -> Tagged s b -> m (Tagged s b) #
Num a => Num (Tagged s a)
Instance details Defined in Data.Tagged Methods (+) :: Tagged s a -> Tagged s a -> Tagged s a # (-) :: Tagged s a -> Tagged s a -> Tagged s a # (*) :: Tagged s a -> Tagged s a -> Tagged s a # negate :: Tagged s a -> Tagged s a # abs :: Tagged s a -> Tagged s a # signum :: Tagged s a -> Tagged s a # fromInteger :: Integer -> Tagged s a #
Ord b => Ord (Tagged s b)
Instance details Defined in Data.Tagged Methods compare :: Tagged s b -> Tagged s b -> Ordering # (<) :: Tagged s b -> Tagged s b -> Bool # (<=) :: Tagged s b -> Tagged s b -> Bool # (>) :: Tagged s b -> Tagged s b -> Bool # (>=) :: Tagged s b -> Tagged s b -> Bool # max :: Tagged s b -> Tagged s b -> Tagged s b # min :: Tagged s b -> Tagged s b -> Tagged s b #
Read b => Read (Tagged s b)
Instance details Defined in Data.Tagged Methods readsPrec :: Int -> ReadS (Tagged s b) # readList :: ReadS [Tagged s b] # readPrec :: ReadPrec (Tagged s b) # readListPrec :: ReadPrec [Tagged s b] #
Real a => Real (Tagged s a)
Instance details Defined in Data.Tagged Methods toRational :: Tagged s a -> Rational #
RealFloat a => RealFloat (Tagged s a)
Instance details Defined in Data.Tagged Methods floatRadix :: Tagged s a -> Integer # floatDigits :: Tagged s a -> Int # floatRange :: Tagged s a -> (Int, Int) # decodeFloat :: Tagged s a -> (Integer, Int) # encodeFloat :: Integer -> Int -> Tagged s a # exponent :: Tagged s a -> Int # significand :: Tagged s a -> Tagged s a # scaleFloat :: Int -> Tagged s a -> Tagged s a # isNaN :: Tagged s a -> Bool # isInfinite :: Tagged s a -> Bool # isDenormalized :: Tagged s a -> Bool # isNegativeZero :: Tagged s a -> Bool # isIEEE :: Tagged s a -> Bool # atan2 :: Tagged s a -> Tagged s a -> Tagged s a #
RealFrac a => RealFrac (Tagged s a)
Instance details Defined in Data.Tagged Methods properFraction :: Integral b => Tagged s a -> (b, Tagged s a) # truncate :: Integral b => Tagged s a -> b # round :: Integral b => Tagged s a -> b # ceiling :: Integral b => Tagged s a -> b # floor :: Integral b => Tagged s a -> b #
Show b => Show (Tagged s b)
Instance details Defined in Data.Tagged Methods showsPrec :: Int -> Tagged s b -> ShowS # show :: Tagged s b -> String # showList :: [Tagged s b] -> ShowS #
Ix b => Ix (Tagged s b)
Instance details Defined in Data.Tagged Methods range :: (Tagged s b, Tagged s b) -> [Tagged s b] # index :: (Tagged s b, Tagged s b) -> Tagged s b -> Int # unsafeIndex :: (Tagged s b, Tagged s b) -> Tagged s b -> Int inRange :: (Tagged s b, Tagged s b) -> Tagged s b -> Bool # rangeSize :: (Tagged s b, Tagged s b) -> Int # unsafeRangeSize :: (Tagged s b, Tagged s b) -> Int
IsString a => IsString (Tagged s a)
Instance details Defined in Data.Tagged Methods fromString :: String -> Tagged s a #
Generic (Tagged s b)
Instance details Defined in Data.Tagged Associated Types type Rep (Tagged s b) :: Type -> Type # Methods from :: Tagged s b -> Rep (Tagged s b) x # to :: Rep (Tagged s b) x -> Tagged s b #
Semigroup a => Semigroup (Tagged s a)
Instance details Defined in Data.Tagged Methods (<>) :: Tagged s a -> Tagged s a -> Tagged s a # sconcat :: NonEmpty (Tagged s a) -> Tagged s a # stimes :: Integral b => b -> Tagged s a -> Tagged s a #
(Semigroup a, Monoid a) => Monoid (Tagged s a)
Instance details Defined in Data.Tagged Methods mempty :: Tagged s a # mappend :: Tagged s a -> Tagged s a -> Tagged s a # mconcat :: [Tagged s a] -> Tagged s a #
Storable a => Storable (Tagged s a)
Instance details Defined in Data.Tagged Methods sizeOf :: Tagged s a -> Int # alignment :: Tagged s a -> Int # peekElemOff :: Ptr (Tagged s a) -> Int -> IO (Tagged s a) # pokeElemOff :: Ptr (Tagged s a) -> Int -> Tagged s a -> IO () # peekByteOff :: Ptr b -> Int -> IO (Tagged s a) # pokeByteOff :: Ptr b -> Int -> Tagged s a -> IO () # peek :: Ptr (Tagged s a) -> IO (Tagged s a) # poke :: Ptr (Tagged s a) -> Tagged s a -> IO () #
Bits a => Bits (Tagged s a)
Instance details Defined in Data.Tagged Methods (.&.) :: Tagged s a -> Tagged s a -> Tagged s a # (.\|.) :: Tagged s a -> Tagged s a -> Tagged s a # xor :: Tagged s a -> Tagged s a -> Tagged s a # complement :: Tagged s a -> Tagged s a # shift :: Tagged s a -> Int -> Tagged s a # rotate :: Tagged s a -> Int -> Tagged s a # zeroBits :: Tagged s a # bit :: Int -> Tagged s a # setBit :: Tagged s a -> Int -> Tagged s a # clearBit :: Tagged s a -> Int -> Tagged s a # complementBit :: Tagged s a -> Int -> Tagged s a # testBit :: Tagged s a -> Int -> Bool # bitSizeMaybe :: Tagged s a -> Maybe Int # bitSize :: Tagged s a -> Int # isSigned :: Tagged s a -> Bool # shiftL :: Tagged s a -> Int -> Tagged s a # unsafeShiftL :: Tagged s a -> Int -> Tagged s a # shiftR :: Tagged s a -> Int -> Tagged s a # unsafeShiftR :: Tagged s a -> Int -> Tagged s a # rotateL :: Tagged s a -> Int -> Tagged s a # rotateR :: Tagged s a -> Int -> Tagged s a # popCount :: Tagged s a -> Int #
FiniteBits a => FiniteBits (Tagged s a)
Instance details Defined in Data.Tagged Methods finiteBitSize :: Tagged s a -> Int # countLeadingZeros :: Tagged s a -> Int # countTrailingZeros :: Tagged s a -> Int #
NFData b => NFData (Tagged s b)
Instance details Defined in Data.Tagged Methods rnf :: Tagged s b -> () #
ToFormKey a => ToFormKey (Tagged b a)
Instance details Defined in Web.Internal.FormUrlEncoded Methods toFormKey :: Tagged b a -> Text #
FromFormKey a => FromFormKey (Tagged b a)
Instance details Defined in Web.Internal.FormUrlEncoded Methods parseFormKey :: Text -> Either Text (Tagged b a) #
ToHttpApiData a => ToHttpApiData (Tagged b a)
Instance details Defined in Web.Internal.HttpApiData Methods toUrlPiece :: Tagged b a -> Text # toEncodedUrlPiece :: Tagged b a -> Builder # toHeader :: Tagged b a -> ByteString # toQueryParam :: Tagged b a -> Text #
FromHttpApiData a => FromHttpApiData (Tagged b a)
Instance details Defined in Web.Internal.HttpApiData Methods parseUrlPiece :: Text -> Either Text (Tagged b a) # parseHeader :: ByteString -> Either Text (Tagged b a) # parseQueryParam :: Text -> Either Text (Tagged b a) #
type Rep1 (Tagged s :: Type -> Type)
Instance details Defined in Data.Tagged type Rep1 (Tagged s :: Type -> Type) = D1 (MetaData "Tagged" "Data.Tagged" "tagged-0.8.6-FABECvKnqYbBCttH1EeJvB" True) (C1 (MetaCons "Tagged" PrefixI True) (S1 (MetaSel (Just "unTagged") NoSourceUnpackedness NoSourceStrictness DecidedLazy) Par1))
type Rep (Tagged s b)
Instance details Defined in Data.Tagged type Rep (Tagged s b) = D1 (MetaData "Tagged" "Data.Tagged" "tagged-0.8.6-FABECvKnqYbBCttH1EeJvB" True) (C1 (MetaCons "Tagged" PrefixI True) (S1 (MetaSel (Just "unTagged") NoSourceUnpackedness NoSourceStrictness DecidedLazy) (Rec0 b)))