Webby
An easy to use Haskell web-server inspired by Scotty.
Build
Clone the repo and run stack build
Example
module Main where
import qualified Network.Wai.Handler.Warp as W
import qualified Network.Wai as W
import Network.HTTP.Types (status500)
import UnliftIO (liftIO)
import qualified UnliftIO.Exception as E
import Relude hiding (get, put)
import Relude.Print (putTextLn)
import qualified Data.Text as T
import Webby
-- An example exception handler web-applications can install with webby
appExceptionHandler :: T.Text -> (E.SomeException -> WebbyM appEnv ())
appExceptionHandler appName = \(exception :: E.SomeException) -> do
setStatus status500
let msg = appName <> " failed with " <> show exception
putTextLn msg
text msg
main :: IO ()
main = do
-- Define the API routes handled by your web-application
let routes = [ get "/api/a" (text "a\n")
, get "/api/b" (text "b\n")
, post "/api/capture/:id"
(do idVal :: Int <- getCapture "id"
text $ (T.pack (show idVal) `T.append` "\n")
)
, get "/api/isOdd/:val"
(do val :: Integer <- getCapture "val"
-- if val is odd return the number else we short-circuit the handler
unless (odd val) finish
text $ show val
)
, get "/api/showEnv" (do env <- getAppEnv
text env
)
, get "/aaah" (liftIO $ E.throwString "oops!")
]
-- Set the routes definition and exception handler for your
-- web-application
webbyConfig = setExceptionHandler (appExceptionHandler "MyApp") $
setRoutes routes $
defaultWebbyServerConfig
-- Application environment in this example is a simple Text literal.
-- Usually, application environment would contain database connections
-- etc.
appEnv = "MyEnv" :: T.Text
webbyApp <- mkWebbyApp appEnv webbyConfig
putStrLn "Starting webserver..."
W.runEnv 7000 webbyApp
You can try the example above, by cloning the repo and running the
example:
$ examples/Basic.hs
In another shell, let’s curl
the server:
$ curl http://localhost:7000/api/a
a
$ curl http://localhost:7000/api/b
b
$ curl -XPOST http://localhost:7000/api/capture/32
32
$ curl http://localhost:7000/api/showEnv
MyEnv
$ curl http://localhost:7000/aaah
MyApp failed with Control.Exception.Safe.throwString called with:
oops!
Called from:
throwString (examples/Basic.hs:55:42 in main:Main)