Snap框架：使用消化函數編譯拼接和處理表單

Question

我正在嘗試理解編譯的拼接以及如何將它們與消化函子形式一起使用。 有人有任何代碼示例嗎？

Answer 1

以下工作用於處理已編譯拼接中的表單...

bookFormSplice :: C.Splice (Handler App App)
bookFormSplice = formSplice $ do
  (view,result) <- DFS.runForm "bookForm" bookForm -- runForm is in Text.Digestive.Snap
  case result of Just x -> redirect "/" --valid result, redirect to the home page
                                        --can also insert into DB here
                 Nothing -> return view --no result or invalid form data,
                                        --return the view and render the form page

附加應用程序，數據，渲染代碼......

data Book = Book { title :: T.Text
               , description :: T.Text }


bookForm :: Monad m => Form T.Text m Book
bookForm = check "Cannot be blank" notBlank $ Book
    <$> "title" .: text (Nothing)
    <*> "description" .: text Nothing
    where
      notBlank (Book t d) = t /= "" && d /= ""




handleNewBook :: Handler App App ()
handleNewBook = cRender "newBook"



routes :: [(ByteString, Handler App App ())]
routes = [ ("/login",    with auth handleLoginSubmit)
     , ("/logout",   with auth handleLogout)
     , ("/new_user", with auth handleNewUser)
     , ("/newBook", handleNewBook)
     , ("",          serveDirectory "static")
     ]


app :: SnapletInit App App
app = makeSnaplet "app" "An snaplet example application." Nothing $ do
h <- nestSnaplet "" heist $ heistInit "templates"
s <- nestSnaplet "sess" sess $
       initCookieSessionManager "site_key.txt" "sess" (Just 3600)
a <- nestSnaplet "auth" auth $
       initJsonFileAuthManager defAuthSettings sess "users.json"

let config = mempty { hcCompiledSplices = [("bookForm", bookFormSplice)]}
addConfig h config
addRoutes routes
addAuthSplices auth
return $ App h s a

“newBook”模板

New Book Entry:
<br>

<bookForm action="/newBook">

<dfChildErrorList ref="" />

<dfInputText ref="title"/>
<dfInputText ref="description"/>
<dfInputSubmit value="submit"/>
</bookForm>