Snap.Snaplet.Router.Types

Documentation

data RouterState

Constructors

RouterState

Fields

_prefix :: Text

class Monad m => HasRouter m where

Instantiate this type class for Handler App App and Handler b RouterState so that the snaplet can find its state. An instance requires a type for URL m - being the URL data type you have defined - and an instance of getRouterState. Assuming your URL data type is called AppUrl, the instance for Handler b RouterState would be

 instance HasRouter (Handler b RouterState) where
     type URL (Handler b RouterState) = AppUrl
     getRouterState = get

If the lens for the Router snaplet is router, your Handler App App instance would be

 instance HasRouter (Handler App App) where
     type URL (Handler App App) = AppUrl
     getRouterState = with router get

Associated Types

type URL m

Methods

getRouterState :: m RouterState

Instances

HasRouter m => HasRouter (HeistT n m)

class PathInfo url

Simple parsing and rendering for a type to and from URL path segments.

If you're using GHC 7.2 or later, you can use DeriveGeneric to derive instances of this class:

 {-# LANGUAGE DeriveGeneric #-}
 data Sitemap = Home | BlogPost Int deriving Generic
 instance PathInfo Sitemap

This results in the following instance:

 instance PathInfo Sitemap where
     toPathSegments Home = ["home"]
     toPathSegments (BlogPost x) = "blog-post" : toPathSegments x
     fromPathSegments = Home <$ segment "home"
                    <|> BlogPost <$ segment "blog-post" <*> fromPathSegments

And here it is in action:

>>> toPathInfo (BlogPost 123)
"/blog-post/123"
>>> fromPathInfo "/blog-post/123" :: Either String Sitemap
Right (BlogPost 123)

To instead derive instances using TemplateHaskell, see web-routes-th.

Instances

PathInfo Int

PathInfo Integer

PathInfo String

PathInfo Text

PathInfo [String]

PathInfo [Text]

Re-exported for convenience

class Generic a

Representable types of kind *. This class is derivable in GHC with the DeriveGeneric flag on.

Instances

Generic Bool

Generic Char

Generic Double

Generic Float

Generic Int

Generic Ordering

Generic ()

Generic Void

Generic [a]

Generic (Maybe a)

Generic (Max a)

Generic (First a)

Generic (Last a)

Generic (WrappedMonoid m)

Generic (Option a)

Generic (Either a b)

Generic (a, b)

Generic (a, b, c)

Generic (a, b, c, d)

Generic (a, b, c, d, e)

Generic (a, b, c, d, e, f)

Generic (a, b, c, d, e, f, g)