Re: [Haskell-cafe] web-routes and forms

21 Jan 2011

      Hello Jeremy,
I'm still trying to integrate web routes, but there is one thing I don't
understand:
how to deal with multiple forms?

In my former application, each forms used to redirect to a subdirectory of
the web site, and an appropriate handler was waiting there.
But now with web routes I don't see how to do that.
I've tried to push down the decision over subdirectories (with the guard
"dir") inside the RouteT monad:

type NomicServer       = ServerPartT IO
type RoutedNomicServer = RouteT PlayerCommand NomicServer

nomicSite :: ServerHandle -> Site PlayerCommand (NomicServer Html)
nomicSite sh = setDefault (Noop 0) Site {
      handleSite         = \f url -> unRouteT (routedNomicHandle sh url) f
    , formatPathSegments = \u -> (toPathSegments u, [])
    , parsePathSegments  = parseSegments fromPathSegments
}

routedNomicHandle :: ServerHandle -> PlayerCommand -> RoutedNomicServer Html
routedNomicHandle sh pc = do
   d <- liftRouteT $ liftIO getDataDir
   msum [dir "Login" $ loginPage,
         dir "postLogin" $ postLogin,
         --nullDir >> fileServe [] d,
         dir "NewRule" $ newRule sh,
         dir "NewGame" $ newGameWeb sh,
         dir "Nomic" $ routedNomicCommands sh pc]

routedNomicCommands :: ServerHandle -> PlayerCommand -> RoutedNomicServer
Html
routedNomicCommands sh (Noop pn)                   = nomicPageComm pn sh
(return ())
routedNomicCommands sh (JoinGame pn game)          = nomicPageComm pn sh
(joinGame game pn)
routedNomicCommands sh (LeaveGame pn)              = nomicPageComm pn sh
(leaveGame pn)
routedNomicCommands sh (SubscribeGame pn game)     = nomicPageComm pn sh
(subscribeGame game pn)
routedNomicCommands sh (UnsubscribeGame pn game)   = nomicPageComm pn sh
(unsubscribeGame game pn)
routedNomicCommands sh (Amend pn)                  = nomicPageComm pn sh
(amendConstitution pn)
routedNomicCommands sh (DoAction pn an ar)         = nomicPageComm pn sh
(doAction' an ar pn)
routedNomicCommands sh (NewRule pn name text code) = nomicPageComm pn sh
(submitRule name text code pn)
routedNomicCommands sh (NewGame pn game)           = nomicPageComm pn sh
(newGame game pn)

loginPage :: RoutedNomicServer Html
loginPage = do
   l <- loginForm
   ok $ H.html $ do
      H.head $ do
        H.title (H.string "Login to Nomic")
        H.link ! rel "stylesheet" ! type_ "text/css" ! href
"/static/css/nomic.css"
        H.meta ! A.httpEquiv "Content-Type" ! content
"text/html;charset=utf-8"
        H.meta ! A.name "keywords" ! A.content "Nomic, game, rules, Haskell,
auto-reference"
      H.body $ do
        H.div ! A.id "container" $ do
           H.div ! A.id "header" $ "Login to Nomic"
           H.div ! A.id "login" $ l
           H.div ! A.id "footer" $ "footer"

loginForm :: RoutedNomicServer Html
loginForm = do
   ok $ H.form ! A.method "POST" ! A.action "/postLogin" ! enctype
"multipart/form-data;charset=UTF-8"  $ do
      H.label ! for "login" $ "Login"
      input ! type_ "text" ! name "login" ! A.id "login" ! tabindex "1" !
accesskey "L"
      H.label ! for "password" $ "Password"
      input ! type_ "text" ! name "password" ! A.id "password" ! tabindex
"2" ! accesskey "P"
      input ! type_  "submit" ! tabindex "3" ! accesskey "S" ! value "Enter
Nomic!"

postLogin :: RoutedNomicServer Html
postLogin = do
  methodM POST -- only accept a post method
  mbEntry <- getData -- get the data
  case mbEntry of
    Nothing -> error $ "error: postLogin"
    Just (LoginPass login password)  -> do
      mpn <- liftRouteT $ liftIO $ newPlayerWeb login password
      case mpn of
         Just pn -> do
            link <- showURL $ Noop pn
            seeOther link $ string "Redirecting..."
         Nothing -> seeOther ("/Login?status=fail" :: String) $ string
"Redirecting..."

launchWebServer :: ServerHandle -> IO ()
launchWebServer sh = do
   putStrLn "Starting web server...\nTo connect, drive your browser to \"
http://localhost:8000/Login\""
   simpleHTTP nullConf $ implSite "http://localhost:8000/" "" (nomicSite sh)

But when I drive my browser to "http://localhost:8000/Login/", happstack
tell me there is nothing here.
Am I doing it right? If yes, I must have made a mistake.
(as you can see I'm still far from putting in disgestive functors ;)

If you need, the complete application can be found here (see file Web.hs):
https://github.com/cdupont/Nomic

Thanks,
Corentin

On Wed, Jan 19, 2011 at 5:12 PM, Corentin Dupont
wrote:
...
Thanks Jeremy.
I had it to work now ;)
Corentin
On Tue, Jan 18, 2011 at 6:01 PM, Jeremy Shaw  wrote:
...
Hello,
trhsx will be installed in ~/.cabal/bin, so you will need to add that
to your PATH.
In order to use the demo code I provided you would need the latest
happstack from darcs because it contains a few differences in the API.
The code can be made to work with what is on hackage though.
The submit issue is actually a bug in digestive-functors-blaze. The
return type should be, Form m i e BlazeFormHtml (). jaspervdj is going
to patch it and upload a new version.
- jeremy
On Thu, Jan 13, 2011 at 2:40 PM, Corentin Dupont
 wrote:
...
Hello,
I'm using the combination happstack + digestive-functors + web-routes +
blazeHTML.
I'm not finding any examples on the net...
I've tried to adapt your example (thanks):
type NomicForm a = HappstackForm IO String BlazeFormHtml a
demoForm :: NomicForm (Text, Text)
demoForm =
    (,) <$> ((TDB.label "greeting: " ++> inputNonEmpty Nothing) <* br)
        <*> ((TDB.label "noun: "     ++> inputNonEmpty Nothing) <* br)
        <*  (submit "submit")
    where
      br :: NomicForm ()
      br = view H.br
      -- make sure the fields are not blank, show errors in line if they
are
      inputNonEmpty :: Maybe Text -> NomicForm Text
      inputNonEmpty v =
          (inputText v `validate` (TD.check "You can not leave this
field
blank." (not . T.null)) <++ errors)
But I've got a problem on submit and inputText. I don't see how they are
compatible with HappstackForm.
NomicForm a reduces to:
Form (ServerPartT IO) Input String BlazeFormHtml a
whereas the type of submit is:
submit :: Monad m
=> String                            -- ^ Text on the submit
button
-> Form m String e BlazeFormHtml ()  -- ^ Submit button
Maybe I miss some instance?
BTW, I also tried to execute your exemple, but I can't install some
packages.
...
cabal install digestive-functors-hsp
cabal: Unknown build tool trhsx
Whereas trhsx is in my PATH (under linux).
You said I need the latest happstack from darcs, why?
Cheers,
Corentin
On Sun, Jan 9, 2011 at 8:36 PM, Jeremy Shaw 
wrote:
...
Hello,
newRule also needs to have the type, RoutedNomicServer. The
transformation of RoutedNomicServer into NomicServer is done in the
handleSite function. Something like this:
nomicSpec :: ServerHandle -> Site Route (ServerPartT IO Response)
nomicSpec sh =
     Site { handleSite          = \f url -> unRouteT (nomicSite sh url)
f
...
...
main =
   do ...
     simpleHTTP nullConf $ siteImpl (nomicSpec sh)
Or something like that -- it's hard to tell exactly what is going on
in your app based on the snippets you provided.
Also, I highly recommend using digestive functors instead of formlets.
It is the successor to formlets. Same core idea, better implementation
and actively maintained.
I have attached a quick demo of using:
happstack+digestive-functors+web-routes+HSP
To use it you will need the latest happstack from darcs plus:
hsp
 web-routes
 web-routes-hsp
 web-routes-happstack
 web-routes-mtl
 digestive-functors
 digestive-functors-hsp
I plan to clean up this example and document it better in the crash
course for the upcoming release. Clearly things like the FormInput
instance and the formPart function belong a library.
let me know if you have more questions.
- jeremy
On Sat, Jan 8, 2011 at 6:44 PM, Corentin Dupont
 wrote:
...
Hello,
I have difficulties mixing web-routes and forms:
I have put routes in all my site, except for forms which remains with
the
type ServerPartT IO Response.
How to make them work together?
I have:
type NomicServer             = ServerPartT IO
type RoutedNomicServer = RouteT PlayerCommand NomicServer
newRule :: ServerHandle -> NomicServer Response
newRule sh = do
   methodM POST -- only accept a post method
   mbEntry <- getData -- get the data
   case mbEntry of
      Nothing -> error $ "error: newRule"
      Just (NewRule name text code pn) -> do
         html <- nomicPageComm pn sh (submitRule name text code pn))
         ok $ toResponse html
nomicPageComm :: PlayerNumber -> ServerHandle -> Comm () ->
RoutedNomicServer Html
nomicPageComm pn sh comm =
(..)
launchWebServer :: ServerHandle -> IO ()
launchWebServer sh = do
   putStrLn "Starting web server...\nTo connect, drive your browser
to
...
...
\"http://localhost:8000/Login\ http://localhost:8000/Login%5C""
   d <- liftIO getDataDir
   simpleHTTP nullConf $ mconcat [dir "postLogin" $ postLogin,
                                  fileServe [] d,
                                  dir "Login" $ ok $ toResponse $
loginPage,
                                  dir "NewRule" $ newRule sh,
                                  dir "NewGame" $ newGameWeb sh,
                                  dir "Nomic" $ do
                                     html <- implSite
"http://localhost:8000/Nomic/" "" (nomicSite sh)
                                     ok $ toResponse html
                                  ]
The red line doesn't compile. I don't know how to transform a
RoutedNomicServer into a NomicServer.
For the future I intend to use formlets: is these some examples of
programs
using happstack + web-routes + formlets?
Thanks,
Corentin
On Fri, Jan 7, 2011 at 5:10 PM, Jeremy Shaw 
wrote:
...
Hello,
The [(String, String)] argument is for adding query parameters.
> encodePathInfo ["foo", "bar", "baz"] [("key","value")]
"foo/bar/baz?key=value"
Instead of showURL you would use showURLParams.
hope this helps!d
- jeremy
On Fri, Jan 7, 2011 at 8:12 AM, Corentin Dupont
 wrote:
> Hello Jeremy,
> I'm using Web routes with happstack.
> I'm following this tutorial:
> http://tutorialpedia.org/tutorials/Happstack+type+safe+URLs.html
>
> But It seems out of synch with the latest version of web-routes:
> 0.23.2.
> The haddock documentation seems out of date also:
>
> encodePathInfo :: [String] -> [(String, String)] -> String
>
> For example:
>
>  encodePathInfo [\"foo\", \"bar\", \"baz\"]
>
> "foo/bar/baz"
>
> And I can't figure out what this [(String, String)] is for ;)
>
> Thanks,
>
> Corentin
>