Copyright	(c) Happstack.com 2010; (c) HAppS Inc 2007
License	BSD3
Maintainer	Happstack team <happs@googlegroups.com>
Stability	provisional
Portability	GHC-only, Windows, Linux, FreeBSD, OS X
Safe Haskell	Safe-Inferred
Language	Haskell2010

Happstack.Server

Contents

HTTP Server
Request Routing
Creating Responses
Looking up values in Query String, Request Body, and Cookies
Create and Set Cookies (see also Happstack.Server.RqData)
File Serving
HTTP Realm Authentication
Error Handling
I18N
Web-related Monads
Output Validation
HTTP Types

Description

Happstack.Server provides a self-contained HTTP server and a rich collection of types and functions for routing Requests, generating Responses, working with query parameters, form data, and cookies, serving files and more.

A very simple, "Hello World!" web app looks like:

import Happstack.Server
main = simpleHTTP nullConf $ ok "Hello World!"

By default the server will listen on port 8000. Run the app and point your browser at: http://localhost:8000/

At the core of the Happstack server we have the simpleHTTP function which starts the HTTP server:

simpleHTTP :: ToMessage a => Conf -> ServerPart a -> IO ()

and we have the user supplied ServerPart (also known as, ServerPartT IO), which generates a Response for each incoming Request.

A trivial HTTP app server might just take a user supplied function like:

myApp :: Request -> IO Response

For each incoming Request the server would fork a new thread, run myApp to generate a Response, and then send the Response back to the client. But, that would be a pretty barren wasteland to work in.

The model for ServerPart is essential the same, except we use the much richer ServerPart monad instead of the IO monad.

For in-depth documentation and runnable examples I highly recommend The Happstack Crash Course http://happstack.com/docs/crashcourse/index.html.

Synopsis

parseConfig :: [String] -> Either [String] Conf
simpleHTTP :: ToMessage a => Conf -> ServerPartT IO a -> IO ()
simpleHTTP' :: (ToMessage b, Monad m, Functor m) => (UnWebT m a -> UnWebT IO b) -> Conf -> ServerPartT m a -> IO ()
simpleHTTP'' :: (ToMessage b, Monad m, Functor m) => ServerPartT m b -> Request -> m Response
simpleHTTPWithSocket :: ToMessage a => Socket -> Conf -> ServerPartT IO a -> IO ()
simpleHTTPWithSocket' :: (ToMessage b, Monad m, Functor m) => (UnWebT m a -> UnWebT IO b) -> Socket -> Conf -> ServerPartT m a -> IO ()
bindPort :: Conf -> IO Socket
bindIPv4 :: String -> Int -> IO Socket
waitForTermination :: IO ()
module Happstack.Server.Routing
module Happstack.Server.Response
module Happstack.Server.RqData
module Happstack.Server.Cookie
module Happstack.Server.FileServe
module Happstack.Server.Auth
module Happstack.Server.Error
module Happstack.Server.I18N
module Happstack.Server.Monads
module Happstack.Server.Validation
module Happstack.Server.Types

HTTP Server

parseConfig :: [String] -> Either [String] Conf Source #

Parse command line options into a Conf.

simpleHTTP :: ToMessage a => Conf -> ServerPartT IO a -> IO () Source #

start the server, and handle requests using the supplied ServerPart.

This function will not return, though it may throw an exception.

NOTE: The server will only listen on IPv4 due to portability issues in the Network module. For IPv6 support, use simpleHTTPWithSocket with custom socket.

simpleHTTP' :: (ToMessage b, Monad m, Functor m) => (UnWebT m a -> UnWebT IO b) -> Conf -> ServerPartT m a -> IO () Source #

A combination of simpleHTTP'' and mapServerPartT. See mapServerPartT for a discussion of the first argument of this function.

NOTE: This function always binds to IPv4 ports until Network module is fixed to support IPv6 in a portable way. Use simpleHTTPWithSocket with custom socket if you want different behaviour.

simpleHTTP'' :: (ToMessage b, Monad m, Functor m) => ServerPartT m b -> Request -> m Response Source #

Generate a result from a ServerPartT and a Request. This is mainly used by CGI (and fast-cgi) wrappers.

simpleHTTPWithSocket :: ToMessage a => Socket -> Conf -> ServerPartT IO a -> IO () Source #

Run simpleHTTP with a previously bound socket. Useful if you want to run happstack as user on port 80. Use something like this:

import System.Posix.User (setUserID, UserEntry(..), getUserEntryForName)

main = do
    let conf = nullConf { port = 80 }
    socket <- bindPort conf
    -- do other stuff as root here
    getUserEntryForName "www" >>= setUserID . userID
    -- finally start handling incoming requests
    tid <- forkIO $ simpleHTTPWithSocket socket Nothing conf impl

Note: It's important to use the same conf (or at least the same port) for bindPort and simpleHTTPWithSocket.