servant-server-0.20.2: A family of combinators for defining webservices APIs and serving them
Safe HaskellSafe-Inferred
LanguageHaskell2010

Servant.Server.Internal.Router

Synopsis

Documentation

data CaptureHint Source #

Holds information about pieces of url that are captured as variables.

Constructors

CaptureHint 

Fields

Instances

Instances details
Show CaptureHint Source # 
Instance details

Defined in Servant.Server.Internal.Router

Eq CaptureHint Source # 
Instance details

Defined in Servant.Server.Internal.Router

data Router' env a Source #

Internal representation of a router.

The first argument describes an environment type that is expected as extra input by the routers at the leaves. The environment is filled while running the router, with path components that can be used to process captures.

Constructors

StaticRouter (Map Text (Router' env a)) [env -> a]

the map contains routers for subpaths (first path component used for lookup and removed afterwards), the list contains handlers for the empty path, to be tried in order

CaptureRouter [CaptureHint] (Router' (Text, env) a)

first path component is passed to the child router in its environment and removed afterwards. The first argument is a list of hints for all variables that can be captured by the router. The fact that it is a list is counter-intuitive, because the Capture combinator only allows to capture a single varible, with a single name and a single type. However, the choice smart constructor may merge two Capture combinators with different hints, thus forcing the type to be '[CaptureHint]'. Because CaptureRouter is built from a Capture combinator, the list of hints should always be non-empty.

CaptureAllRouter [CaptureHint] (Router' ([Text], env) a)

all path components are passed to the child router in its environment and are removed afterwards The first argument is a hint for the list of variables that can be captured by the router. Note that the $sel:captureType:CaptureHint field of the hint should always be '[a]' for some a.

RawRouter (env -> a)

to be used for routes we do not know anything about

Choice (Router' env a) (Router' env a)

left-biased choice between two routers

Instances

Instances details
Functor (Router' env) Source # 
Instance details

Defined in Servant.Server.Internal.Router

Methods

fmap :: (a -> b) -> Router' env a -> Router' env b #

(<$) :: a -> Router' env b -> Router' env a #

pathRouter :: Text -> Router' env a -> Router' env a Source #

Smart constructor for a single static path component.

leafRouter :: (env -> a) -> Router' env a Source #

Smart constructor for a leaf, i.e., a router that expects the empty path.

choice :: Router' env a -> Router' env a -> Router' env a Source #

Smart constructor for the choice between routers. We currently optimize the following cases:

  • Two static routers can be joined by joining their maps and concatenating their leaf-lists.
  • Two dynamic routers can be joined by joining their codomains.
  • Choice nodes can be reordered.

data RouterStructure Source #

Datatype used for representing and debugging the structure of a router. Abstracts from the handlers at the leaves.

Two Routers can be structurally compared by computing their RouterStructure using routerStructure and then testing for equality, see sameStructure.

Constructors

StaticRouterStructure (Map Text RouterStructure) Int 
CaptureRouterStructure [CaptureHint] RouterStructure

The first argument holds information about variables that are captured by the router. There may be several hints if several routers have been aggregated by the choice smart constructor.

RawRouterStructure 
ChoiceStructure RouterStructure RouterStructure 

routerStructure :: Router' env a -> RouterStructure Source #

Compute the structure of a router.

Assumes that the request or text being passed in WithRequest or CaptureRouter does not affect the structure of the underlying tree.

sameStructure :: Router' env a -> Router' env b -> Bool Source #

Compare the structure of two routers.

routerLayout :: Router' env a -> Text Source #

Provide a textual representation of the structure of a router.

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

Apply a transformation to the response of a Router.

runRouter :: NotFoundErrorFormatter -> Router () -> RoutingApplication Source #

Interpret a router as an application.

runChoice :: NotFoundErrorFormatter -> [env -> RoutingApplication] -> env -> RoutingApplication Source #

Try a list of routing applications in order. We stop as soon as one fails fatally or succeeds. If all fail normally, we pick the "best" error.