Webby

Documentation

data WebbyM env a

The main monad transformer stack used in the web-framework.

The type of a handler for a request is `WebbyM appEnv ()`. The appEnv parameter is used by the web application to store an (read-only) environment. For e.g. it can be used to store a database connection pool.

Instances

Monad (WebbyM env)

Defined in Webby.Types

Methods

(>>=) :: WebbyM env a -> (a -> WebbyM env b) -> WebbyM env b

(>>) :: WebbyM env a -> WebbyM env b -> WebbyM env b

return :: a -> WebbyM env a

fail :: String -> WebbyM env a

Functor (WebbyM env)

Defined in Webby.Types

Methods

fmap :: (a -> b) -> WebbyM env a -> WebbyM env b

(<$) :: a -> WebbyM env b -> WebbyM env a

Applicative (WebbyM env)

Defined in Webby.Types

Methods

pure :: a -> WebbyM env a

(<*>) :: WebbyM env (a -> b) -> WebbyM env a -> WebbyM env b

liftA2 :: (a -> b -> c) -> WebbyM env a -> WebbyM env b -> WebbyM env c

(*>) :: WebbyM env a -> WebbyM env b -> WebbyM env b

(<*) :: WebbyM env a -> WebbyM env b -> WebbyM env a

MonadIO (WebbyM env)

Defined in Webby.Types

Methods

liftIO :: IO a -> WebbyM env a

MonadUnliftIO (WebbyM appData)

Defined in Webby.Types

Methods

askUnliftIO :: WebbyM appData (UnliftIO (WebbyM appData))

withRunInIO :: ((forall a. WebbyM appData a -> IO a) -> IO b) -> WebbyM appData b

MonadReader (WEnv env) (WebbyM env)

Defined in Webby.Types

Methods

ask :: WebbyM env (WEnv env)

local :: (WEnv env -> WEnv env) -> WebbyM env a -> WebbyM env a

reader :: (WEnv env -> a) -> WebbyM env a

Routing and handler functions

data RoutePattern

A route pattern represents logic to match a request to a handler.

Instances

Eq RoutePattern

Defined in Webby.Types

Methods

(==) :: RoutePattern -> RoutePattern -> Bool

(/=) :: RoutePattern -> RoutePattern -> Bool

Show RoutePattern

Defined in Webby.Types

Methods

showsPrec :: Int -> RoutePattern -> ShowS

show :: RoutePattern -> String

showList :: [RoutePattern] -> ShowS

type Route env = (RoutePattern, WebbyM env ())

A route is a pair of a route pattern and a handler.

mkRoute :: Method -> Text -> WebbyM appEnv () -> (RoutePattern, WebbyM appEnv ())

Create a route for a user-provided HTTP request method, pattern and handler function.

post :: Text -> WebbyM appEnv () -> (RoutePattern, WebbyM appEnv ())

Create a route for a POST request method, given the path pattern and handler.

get :: Text -> WebbyM appEnv () -> (RoutePattern, WebbyM appEnv ())

Create a route for a GET request method, given the path pattern and handler.

put :: Text -> WebbyM appEnv () -> (RoutePattern, WebbyM appEnv ())

Create a route for a PUT request method, given the path pattern and handler.

delete :: Text -> WebbyM appEnv () -> (RoutePattern, WebbyM appEnv ())

Create a route for a DELETE request method, given path pattern and handler.

Captures

type Captures = HashMap Text Text

Captures are simply extracted path elements in a HashMap

captures :: WebbyM appEnv Captures

Retrieve all path captures

getCapture :: FromHttpApiData a => Text -> WebbyM appEnv a

Retrieve a particular capture (TODO: extend?)

Request parsing

flag :: Text -> WebbyM appEnv Bool

header :: HeaderName -> WebbyM appEnv (Maybe Text)

headers :: WebbyM appEnv [Header]

jsonData :: FromJSON a => WebbyM appEnv a

param :: FromHttpApiData a => Text -> WebbyM appEnv (Maybe a)

param_ :: FromHttpApiData a => Text -> WebbyM appEnv a

params :: WebbyM appEnv [(Text, Text)]

request :: WebbyM appEnv Request

requestBodyLBS :: WebbyM appEnv LByteString

Return the raw request body as a lazy bytestring

requestBodyLength :: WebbyM appEnv (Maybe Int64)

getRequestBodyChunkAction :: WebbyM appEnv (WebbyM appEnv ByteString)

Returns an action that returns successive chunks of the rquest body. It returns an empty bytestring after the request body is consumed.

Response modification

setStatus :: Status -> WebbyM appEnv ()

addHeader :: Header -> WebbyM appEnv ()

setHeader :: Header -> WebbyM appEnv ()

blob :: ByteString -> WebbyM appEnv ()

json :: ToJSON b => b -> WebbyM appEnv ()

text :: Text -> WebbyM appEnv ()

stream :: StreamingBody -> WebbyM appEnv ()

Application

mkWebbyApp :: env -> WebbyServerConfig env -> IO Application

Use this function, to create a WAI application. It takes a user/application defined appEnv data type and a list of routes. Routes are matched in the given order. If none of the requests match a request, a default 404 response is returned.

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")

Application context

data WEnv env

The reader environment used by the web framework. It is parameterized by the application's environment data type.

Instances

MonadReader (WEnv env) (WebbyM env)

Defined in Webby.Types

Methods

ask :: WebbyM env (WEnv env)

local :: (WEnv env -> WEnv env) -> WebbyM env a -> WebbyM env a

reader :: (WEnv env -> a) -> WebbyM env a

getAppEnv :: WebbyM appEnv appEnv

Retrieve the app environment given to the application at initialization.

runAppEnv :: ReaderT appEnv (WebbyM appEnv) a -> WebbyM appEnv a

Webby server configuration

data WebbyServerConfig env

defaultWebbyServerConfig :: WebbyServerConfig env

setRoutes :: [Route env] -> WebbyServerConfig env -> WebbyServerConfig env

setExceptionHandler :: Exception e => (e -> WebbyM env ()) -> WebbyServerConfig env -> WebbyServerConfig env

Handler flow control

finish :: WebbyM appEnv a

Exceptions thrown

data WebbyError

Various kinds of errors thrown by this library - these can be caught by handler code.

Constructors

WebbyJSONParseError Text

WebbyParamParseError

Fields

• wppeParamName :: Text
• wppeErrMsg :: Text

WebbyMissingCapture Text

Instances

Show WebbyError

Defined in Webby.Types

Methods

showsPrec :: Int -> WebbyError -> ShowS

show :: WebbyError -> String

showList :: [WebbyError] -> ShowS

Exception WebbyError

Defined in Webby.Types

Methods

toException :: WebbyError -> SomeException

fromException :: SomeException -> Maybe WebbyError

displayException :: WebbyError -> String