servant-server-0.11: A family of combinators for defining webservices APIs and serving them

Safe Haskell | None
Language | Haskell2010

Servant.Server.Internal.Router

Synopsis

- type Router env = Router' env RoutingApplication
- data Router' env a
  - = StaticRouter (Map Text (Router' env a)) [env -> a]
  - | CaptureRouter (Router' (Text, env) a)
  - | CaptureAllRouter (Router' ([Text], env) a)
  - | RawRouter (env -> a)
  - | Choice (Router' env a) (Router' env a)
- pathRouter :: Text -> Router' env a -> Router' env a
- leafRouter :: (env -> a) -> Router' env a
- choice :: Router' env a -> Router' env a -> Router' env a
- data RouterStructure
  - = StaticRouterStructure (Map Text RouterStructure) Int
  - | CaptureRouterStructure RouterStructure
  - | RawRouterStructure
  - | ChoiceStructure RouterStructure RouterStructure
- routerStructure :: Router' env a -> RouterStructure
- sameStructure :: Router' env a -> Router' env b -> Bool
- routerLayout :: Router' env a -> Text
- tweakResponse :: (RouteResult Response -> RouteResult Response) -> Router env -> Router env
- runRouter :: Router () -> RoutingApplication
- runRouterEnv :: Router env -> env -> RoutingApplication
- runChoice :: [env -> RoutingApplication] -> env -> RoutingApplication
- worseHTTPCode :: Int -> Int -> Bool

# Documentation

type Router env = Router' env RoutingApplication #

data Router' env a #

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 (Router' (Text, env) a) | first path component is passed to the child router in its environment and removed afterwards
CaptureAllRouter (Router' ([Text], env) a) | all path components are passed to the child router in its environment and are removed afterwards
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

Functor (Router' env) # |
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 #

Smart constructor for a single static path component.

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

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

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

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 #

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

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

Constructors

StaticRouterStructure (Map Text RouterStructure) Int |
CaptureRouterStructure RouterStructure |
RawRouterStructure |
ChoiceStructure RouterStructure RouterStructure |

Instances

Eq RouterStructure # |
Methods (==) :: RouterStructure -> RouterStructure -> Bool # (/=) :: RouterStructure -> RouterStructure -> Bool #
Show RouterStructure # |
Methods showsPrec :: Int -> RouterStructure -> ShowS # show :: RouterStructure -> String # showList :: [RouterStructure] -> ShowS #

routerStructure :: Router' env a -> RouterStructure #

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 #

Compare the structure of two routers.

routerLayout :: Router' env a -> Text #

Provide a textual representation of the structure of a router.

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

Apply a transformation to the response of a `Router`.

runRouter :: Router () -> RoutingApplication #

Interpret a router as an application.

runRouterEnv :: Router env -> env -> RoutingApplication #

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

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.

worseHTTPCode :: Int -> Int -> Bool #