| Safe Haskell | None |
|---|
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
- scottyOpts :: Options -> ScottyM () -> IO ()
- data Options = Options {}
- middleware :: Middleware -> ScottyM ()
- get :: RoutePattern -> ActionM () -> ScottyM ()
- post :: RoutePattern -> ActionM () -> ScottyM ()
- put :: RoutePattern -> ActionM () -> ScottyM ()
- delete :: RoutePattern -> ActionM () -> ScottyM ()
- patch :: RoutePattern -> ActionM () -> ScottyM ()
- addroute :: StdMethod -> RoutePattern -> ActionM () -> ScottyM ()
- matchAny :: RoutePattern -> ActionM () -> ScottyM ()
- notFound :: ActionM () -> ScottyM ()
- capture :: String -> RoutePattern
- regex :: String -> RoutePattern
- function :: (Request -> Maybe [Param]) -> RoutePattern
- literal :: String -> RoutePattern
- request :: ActionM Request
- reqHeader :: Text -> ActionM (Maybe Text)
- body :: ActionM ByteString
- param :: Parsable a => Text -> ActionM a
- params :: ActionM [Param]
- jsonData :: FromJSON a => ActionM a
- files :: ActionM [File]
- status :: Status -> ActionM ()
- addHeader :: Text -> Text -> ActionM ()
- setHeader :: Text -> Text -> ActionM ()
- redirect :: Text -> ActionM a
- text :: Text -> ActionM ()
- html :: Text -> ActionM ()
- file :: FilePath -> ActionM ()
- json :: ToJSON a => a -> ActionM ()
- source :: Source (ResourceT IO) (Flush Builder) -> ActionM ()
- raw :: ByteString -> ActionM ()
- raise :: Text -> ActionM a
- rescue :: ActionM a -> (Text -> ActionM a) -> ActionM a
- next :: ActionM a
- type Param = (Text, Text)
- class Parsable a where
- parseParam :: Text -> Either Text a
- parseParamList :: Text -> Either Text [a]
- readEither :: Read a => Text -> Either Text a
- type ScottyM a = ScottyT IO a
- type ActionM a = ActionT IO a
- data RoutePattern
- type File = (Text, FileInfo ByteString)
scotty-to-WAI
scottyApp :: ScottyM () -> IO Application
Turn a scotty application into a WAI Application, which can be
run with any WAI handler.
scottyOpts :: Options -> ScottyM () -> IO ()
Run a scotty application using the warp server, passing extra options.
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 ()
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.
get :: RoutePattern -> ActionM () -> ScottyM ()
get = addroute GET
post :: RoutePattern -> ActionM () -> ScottyM ()
post = addroute POST
put :: RoutePattern -> ActionM () -> ScottyM ()
put = addroute PUT
delete :: RoutePattern -> ActionM () -> ScottyM ()
delete = addroute DELETE
patch :: RoutePattern -> ActionM () -> ScottyM ()
patch = addroute PATCH
addroute :: StdMethod -> RoutePattern -> ActionM () -> ScottyM ()
Define a route with a StdMethod, Text value representing the path spec,
and a body (Action) 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
matchAny :: RoutePattern -> ActionM () -> ScottyM ()
Add a route that matches regardless of the HTTP verb.
notFound :: ActionM () -> ScottyM ()
Specify an action to take if nothing else is found. Note: this _always_ matches, so should generally be the last route specified.
Route Patterns
capture :: String -> RoutePattern
Standard Sinatra-style route. Named captures are prepended with colons. This is the default route type generated by OverloadedString routes. i.e.
get (capture "/foo/:bar") $ ...
and
{-# LANGUAGE OverloadedStrings #-}
...
get "/foo/:bar" $ ...
are equivalent.
regex :: String -> RoutePattern
Match requests using a regular expression. Named captures are not yet supported.
get (regex "^/f(.*)r$") $ do
path <- param "0"
cap <- param "1"
text $ mconcat ["Path: ", path, "\nCapture: ", cap]
>>>curl http://localhost:3000/foo/barPath: /foo/bar Capture: oo/ba
function :: (Request -> Maybe [Param]) -> RoutePattern
Build a route based on a function which can match using the entire Request object.
Nothing indicates the route does not match. A Just value indicates
a successful match, optionally returning a list of key-value pairs accessible
by param.
get (function $ \req -> Just [("version", pack $ show $ httpVersion req)]) $ do
v <- param "version"
text v
>>>curl http://localhost:3000/HTTP/1.1
literal :: String -> RoutePattern
Build a route that requires the requested path match exactly, without captures.
Accessing the Request, Captures, and Query Parameters
Get the request body.
param :: Parsable a => Text -> ActionM a
Get a parameter. First looks in captures, then form data, then query parameters.
jsonData :: FromJSON a => ActionM a
Parse the request body as a JSON object and return it. Raises an exception if parse is unsuccessful.
Modifying the Response and Redirecting
addHeader :: Text -> Text -> ActionM ()
Add to the response headers. Header names are case-insensitive.
setHeader :: Text -> Text -> ActionM ()
Set one of the response headers. Will override any previously set value for that header. Header names are case-insensitive.
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 Body
Note: only one of these should be present in any given route
definition, as they completely replace the current Response body.
Set the body of the response to the given Text value. Also sets "Content-Type"
header to "text/plain".
Set the body of the response to the given Text value. Also sets "Content-Type"
header to "text/html".
file :: FilePath -> ActionM ()
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 ()
Set the body of the response to the JSON encoding of the given value. Also sets "Content-Type" header to "application/json".
source :: Source (ResourceT IO) (Flush Builder) -> ActionM ()
Set the body of the response to a Source. Doesn't set the
"Content-Type" header, so you probably want to do that on your
own with header.
raw :: ByteString -> ActionM ()
Set the body of the response to the given ByteString value. Doesn't set the
"Content-Type" header, so you probably want to do that on your own with header.
Exceptions
Throw an exception, which can be caught with rescue. Uncaught exceptions
turn into HTTP 500 responses.
rescue :: ActionM a -> (Text -> ActionM a) -> ActionM a
Catch an exception thrown by raise.
raise "just kidding" `rescue` (\msg -> text msg)
Abort execution of this action and continue pattern matching routes.
Like an exception, any code after next is not executed.
As an example, these two routes overlap. The only way the second one will
ever run is if the first one calls next.
get "/foo/:number" $ do n <- param "number" unless (all isDigit n) $ next text "a number" get "/foo/:bar" $ do bar <- param "bar" text "not a number"
Parsing Parameters
class Parsable a where
Minimum implemention: parseParam
Methods
parseParam :: Text -> Either Text a
Take a Text value and parse it as a, or fail with a message.
parseParamList :: Text -> Either Text [a]
Default implementation parses comma-delimited lists.
parseParamList t = mapM parseParam (T.split (== ',') t)
Instances
| Parsable Bool | |
| Parsable Char | Overrides default |
| Parsable Double | |
| Parsable Float | |
| Parsable Int | |
| Parsable Integer | |
| Parsable () | Checks if parameter is present and is null-valued, not a literal '()'.
If the URI requested is: '/foo?bar=()&baz' then |
| Parsable ByteString | |
| Parsable Text | |
| Parsable a => Parsable [a] |
readEither :: Read a => Text -> Either Text a
Types
data RoutePattern
Instances
type File = (Text, FileInfo ByteString)