Web.Scotty
Contents
Description
It should be noted that most of the code snippets below depend on the OverloadedStrings language pragma.
- scotty :: Port -> ScottyM () -> IO ()
- scottyApp :: ScottyM () -> IO Application
- middleware :: Middleware -> ScottyM ()
- get :: Text -> ActionM () -> ScottyM ()
- post :: Text -> ActionM () -> ScottyM ()
- put :: Text -> ActionM () -> ScottyM ()
- delete :: Text -> ActionM () -> ScottyM ()
- addroute :: StdMethod -> Text -> ActionM () -> ScottyM ()
- request :: ActionM Request
- param :: Text -> ActionM Text
- status :: Status -> ActionM ()
- header :: Text -> Text -> ActionM ()
- redirect :: Text -> ActionM ()
- text :: Text -> ActionM ()
- html :: Text -> ActionM ()
- file :: FilePath -> ActionM ()
- json :: ToJSON a => a -> ActionM ()
- raise :: Text -> ActionM a
- rescue :: ActionM a -> (Text -> ActionM a) -> ActionM a
- data ScottyM a
- data ActionM a
scotty-to-WAI
scottyApp :: ScottyM () -> IO ApplicationSource
Turn a scotty application into a WAI Application, which can be
run with any WAI handler.
Defining Middleware and Routes
Middleware and routes are run in the order in which they
are defined. All middleware is run first, followed by the first
route that matches. If no route matches, a 404 response is given.
middleware :: Middleware -> ScottyM ()Source
Use given middleware. Middleware is nested such that the first declared is the outermost middleware (it has first dibs on the request and last action on the response). Every middleware is run on each request.
addroute :: StdMethod -> Text -> ActionM () -> ScottyM ()Source
Define a route with a StdMethod, Text value representing the path spec,
and a body (ActionM) which modifies the response.
addroute GET "/" $ text "beam me up!"
The path spec can include values starting with a colon, which are interpreted
as captures. These are named wildcards that can be looked up with param.
addroute GET "/foo/:bar" $ do
v <- param "bar"
text v
>>>curl http://localhost:3000/foo/somethingsomething
Defining Actions
Accessing the Request, Captures, and Query Parameters
param :: Text -> ActionM TextSource
Get a parameter. First looks in captures, then form data, then query parameters. Raises
an exception which can be caught by rescue if parameter is not found.
Modifying the Response and Redirecting
header :: Text -> Text -> ActionM ()Source
Set one of the response headers. Will override any previously set value for that header. Header names are case-insensitive.
redirect :: Text -> ActionM ()Source
Redirect to given URL. Like throwing an uncatchable exception. Any code after the call to redirect will not be run.
redirect "http://www.google.com"
OR
redirect "/foo/bar"
Setting Response
Note: only one of these should be present in any given route
definition, as they completely replace the current Response body.
text :: Text -> ActionM ()Source
Set the body of the response to the given Text value. Also sets "Content-Type"
header to "text/plain".
html :: Text -> ActionM ()Source
Set the body of the response to the given Text value. Also sets "Content-Type"
header to "text/html".
file :: FilePath -> ActionM ()Source
Send a file as the response. Doesn't set the "Content-Type" header, so you probably
want to do that on your own with header.
json :: ToJSON a => a -> ActionM ()Source
Set the body of the response to the JSON encoding of the given value. Also sets "Content-Type" header to "application/json".
Exceptions
raise :: Text -> ActionM aSource
Throw an exception, which can be caught with rescue. Uncaught exceptions
turn into HTTP 500 responses.
rescue :: ActionM a -> (Text -> ActionM a) -> ActionM aSource
Catch an exception thrown by raise.
raise "just kidding" `rescue` (\msg -> text msg)