Foundation.hs

{-# LANGUAGE DataKinds             #-}
{-# LANGUAGE FlexibleInstances     #-}
{-# LANGUAGE InstanceSigs          #-}
{-# LANGUAGE LambdaCase            #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE NoImplicitPrelude     #-}
{-# LANGUAGE OverloadedStrings     #-}
{-# LANGUAGE RecordWildCards       #-}
{-# LANGUAGE TemplateHaskell       #-}
{-# LANGUAGE TypeFamilies          #-}

module Foundation
  ( App(..)
  , Handler
  , Widget
  , Form
  , Route(..)
  , resourcesApp
  , unsafeHandler
  ) where

import qualified Control.Monad.Catch  as MC
import           Control.Monad.Logger (LogSource)
import qualified Data.CaseInsensitive as CI
import qualified Data.Text.Encoding   as TE
import           Data.Time.Clock      (NominalDiffTime)
import           Import.NoFoundation  as Pre
import           Text.Hamlet          (hamletFile)
import           Text.Jasmine         (minifym)
import           Yesod.Core.Types     (Logger)
import qualified Yesod.Core.Unsafe    as Unsafe
import           Yesod.Default.Util   (addStaticContentExternal)

-- | The foundation datatype for your application. This can be a good place to
-- keep settings and values requiring initialization before your application
-- starts running, such as database connections. Every handler will have
-- access to the data present here.
data App = App
  { appSettings    :: AppSettings
  , appStatic      :: Static -- ^ Settings for static file serving.
  , appHttpManager :: Manager
  , appLogger      :: Logger
  , appCalendarCxt :: CalendarContext
  , appGetCalendar :: Maybe NominalDiffTime -> HandlerFor App [SimpleEventUTC]
    -- ^ Fetch latest available times from the calendars. Return cached
    -- version if it's less than given age, which defaults to
    -- 'appCacheExpiry'.
  }

-- This is where we define all of the routes in our application. For a full
-- explanation of the syntax, please see:
-- http://www.yesodweb.com/book/routing-and-handlers
--
-- Note that this is really half the story; in Application.hs, mkYesodDispatch
-- generates the rest of the code. Please see the following documentation
-- for an explanation for this split:
-- http://www.yesodweb.com/book/scaffolding-and-the-site-template#scaffolding-and-the-site-template_foundation_and_application_modules
--
-- This function also generates the following type synonyms:
-- type Handler = HandlerT App IO
-- type Widget = WidgetT App IO ()
mkYesodData "App" $(parseRoutesFile "config/routes")

-- | A convenient synonym for creating forms.
type Form x = Html -> MForm (HandlerFor App) (FormResult x, Widget)

instance MC.MonadCatch (HandlerFor App) where
  catch = Pre.catch

addStylesheetL :: Route App -> Text -> [(Text, Text)] -> Widget
addStylesheetL route cdn attrs =
  appLocalAssets . appSettings <$> getYesod >>= \case
    True -> addStylesheet route
    False -> addStylesheetRemoteAttrs cdn attrs

addScriptL :: Route App -> Text -> [(Text, Text)] -> Widget
addScriptL route cdn attrs =
  appLocalAssets . appSettings <$> getYesod >>= \case
    True -> addScript route
    False -> addScriptRemoteAttrs cdn attrs

-- Please see the documentation for the Yesod typeclass. There are a number
-- of settings which can be configured by overriding methods here.
instance Yesod App where
  approot :: Approot App
  approot =
    ApprootRequest $ \app req ->
      case appRoot $ appSettings app of
        Nothing   -> getApprootText guessApproot app req
        Just root -> root
    -- Store session data on the client in encrypted cookies,
    -- default session idle timeout is 120 minutes
  makeSessionBackend :: App -> IO (Maybe SessionBackend)
  makeSessionBackend _ =
    Just <$>
    defaultClientSessionBackend
      120 -- timeout in minutes
      "config/client_session_key.aes"
    -- Yesod Middleware allows you to run code before and after each handler function.
    -- The defaultYesodMiddleware adds the response header "Vary: Accept, Accept-Language" and performs authorization checks.
    -- Some users may also want to add the defaultCsrfMiddleware, which:
    --   a) Sets a cookie with a CSRF token in it.
    --   b) Validates that incoming write requests include that token in either a header or POST parameter.
    -- To add it, chain it together with the defaultMiddleware: yesodMiddleware = defaultYesodMiddleware . defaultCsrfMiddleware
    -- For details, see the CSRF documentation in the Yesod.Core.Handler module of the yesod-core package.
  yesodMiddleware :: ToTypedContent res => Handler res -> Handler res
  yesodMiddleware = defaultYesodMiddleware
  defaultLayout :: Widget -> Handler Html
  defaultLayout widget = do
    master <- getYesod
    mmsg <- getMessage
    pc <-
      widgetToPageContent $ do
        let fontFamily =
              asText "'Play', 'Helvetica Neue', Helvetica, Arial, sans-serif"
        addScriptL
          (StaticR js_jquery_3_3_1_min_js)
          "https://code.jquery.com/jquery-3.3.1.min.js"
          [ ("integrity", "sha256-FgpCb/KJQlLNfOu91ta32o/NMZxltwRo8QtmkMRdAu8=")
          , ("crossorigin", "anonymous")
          ]
        addScriptL
          (StaticR js_js_cookie_2_2_0_min_js)
          "https://cdn.jsdelivr.net/npm/js-cookie@2.2.0/src/js.cookie.min.js"
          []
        addStylesheetRemote
          "https://fonts.googleapis.com/css?family=Play:400,700"
        addStylesheetL
          (StaticR css_bootstrap_3_3_7_min_css)
          "https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css"
          [ ( "integrity"
            , "sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u")
          , ("crossorigin", "anonymous")
          ]
        --   $ StaticR css_bootstrap_css
        $(widgetFile "default-layout")
    withUrlRenderer $(hamletFile "templates/default-layout-wrapper.hamlet")
  isAuthorized ::
       Route App -- ^ The route the user is visiting.
    -> Bool -- ^ Whether or not this is a "write" request.
    -> Handler AuthResult
    -- Routes not requiring authenitcation.
  isAuthorized FaviconR _ = return Authorized
  isAuthorized RobotsR _  = return Authorized
    -- Default to Authorized for now.
  isAuthorized _ _        = return Authorized
    -- This function creates static content files in the static folder
    -- and names them based on a hash of their content. This allows
    -- expiration dates to be set far in the future without worry of
    -- users receiving stale content.
  addStaticContent ::
       Text -- ^ The file extension
    -> Text -- ^ The MIME content type
    -> LByteString -- ^ The contents of the file
    -> Handler (Maybe (Either Text (Route App, [(Text, Text)])))
  addStaticContent ext mime content = do
    master <- getYesod
    let staticDir = appStaticDir $ appSettings master
    addStaticContentExternal
      minifym
      genFileName
      staticDir
      (StaticR . flip StaticRoute [])
      ext
      mime
      content
        -- Generate a unique filename based on the content itself
    where
      genFileName lbs = "autogen-" ++ base64md5 lbs
    -- What messages should be logged. The following includes all messages when
    -- in development, and warnings and errors in production.
  shouldLogIO :: App -> LogSource -> LogLevel -> IO Bool
  shouldLogIO app _source level =
    return $
    appShouldLogAll (appSettings app) ||
    level == LevelWarn || level == LevelError
  makeLogger :: App -> IO Logger
  makeLogger = return . appLogger

-- Define breadcrumbs.
instance YesodBreadcrumbs App
    -- Takes the route that the user is currently on, and returns a tuple
    -- of the 'Text' that you want the label to display, and a previous
    -- breadcrumb route.
                         where
  breadcrumb ::
       Route App -- ^ The route the user is visiting currently.
    -> Handler (Text, Maybe (Route App))
  breadcrumb HomeR = return ("Home", Nothing)
  breadcrumb _     = return ("home", Nothing)

-- This instance is required to use forms. You can modify renderMessage to
-- achieve customized and internationalized form validation messages.
instance RenderMessage App FormMessage where
  renderMessage :: App -> [Lang] -> FormMessage -> Text
  renderMessage _ _ = defaultFormMessage

-- Useful when writing code that is re-usable outside of the Handler context.
-- An example is background jobs that send email.
-- This can also be useful for writing code that works across multiple Yesod applications.
instance HasHttpManager App where
  getHttpManager :: App -> Manager
  getHttpManager = appHttpManager

unsafeHandler :: App -> Handler a -> IO a
unsafeHandler = Unsafe.fakeHandlerGetLogger appLogger