yesod-eventsource (empty) → 1.0

raw patch · 4 files changed

+167/−0 lines, 4 filesdep +basedep +blaze-builderdep +conduitsetup-changed

Dependencies added: base, blaze-builder, conduit, transformers, wai, wai-eventsource, yesod-core

Files

LICENSE +20/−0
Setup.lhs +7/−0
Yesod/EventSource.hs +98/−0
yesod-eventsource.cabal +42/−0

+ LICENSE view

@@ -0,0 +1,20 @@+Copyright (c) 2012 Felipe Lessa++Permission is hereby granted, free of charge, to any person obtaining+a copy of this software and associated documentation files (the+"Software"), to deal in the Software without restriction, including+without limitation the rights to use, copy, modify, merge, publish,+distribute, sublicense, and/or sell copies of the Software, and to+permit persons to whom the Software is furnished to do so, subject to+the following conditions:++The above copyright notice and this permission notice shall be+included in all copies or substantial portions of the Software.++THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

+ Setup.lhs view

@@ -0,0 +1,7 @@+#!/usr/bin/env runhaskell++> module Main where+> import Distribution.Simple++> main :: IO ()+> main = defaultMain

+ Yesod/EventSource.hs view

@@ -0,0 +1,98 @@+{-# LANGUAGE OverloadedStrings #-}+-- | This module contains everything that you need to support+-- server-sent events in Yesod applications.+module Yesod.EventSource+  ( RepEventSource+  , repEventSource+  , ioToRepEventSource+  , EventSourcePolyfill(..)+  ) where++import Blaze.ByteString.Builder (Builder)+import Control.Monad (when)+import Control.Monad.IO.Class (liftIO)+import Data.Functor ((<$>))+import Data.Monoid (mconcat)+import Yesod.Content+import Yesod.Core+import qualified Data.Conduit as C+import qualified Network.Wai as W+import qualified Network.Wai.EventSource as ES+import qualified Network.Wai.EventSource.EventStream as ES++++-- | Phantom type used for 'Handler'@s@ that are @EventSources@+-- (e.g. 'repEventSource' and 'ioToRepEventSource').+newtype RepEventSource =+  RepEventSource (C.Source (C.ResourceT IO) (C.Flush Builder))++instance HasReps RepEventSource where+  chooseRep (RepEventSource src) =+    const $ return ("text/event-stream", ContentSource src)+++-- | (Internal) Find out the request's 'EventSourcePolyfill' and+-- set any necessary headers.+prepareForEventSource :: GHandler sub master EventSourcePolyfill+prepareForEventSource = do+  reqWith <- lookup "X-Requested-With" . W.requestHeaders <$> waiRequest+  let polyfill | reqWith == Just "XMLHttpRequest" = Remy'sESPolyfill+               | otherwise                        = NoESPolyfill+  setHeader "Cache-Control" "no-cache" -- extremely important!+  return polyfill+++-- | Returns a Server-Sent Event stream from a 'C.Source' of+-- 'ES.ServerEvent'@s@.  The HTTP socket is flushed after every+-- event.  The connection is closed either when the 'C.Source'+-- finishes outputting data or a 'ES.CloseEvent' is outputted,+-- whichever comes first.+repEventSource :: (EventSourcePolyfill -> C.Source (C.ResourceT IO) ES.ServerEvent)+               -> GHandler sub master RepEventSource+repEventSource src = RepEventSource . ES.sourceToSource . src <$> prepareForEventSource+++-- | Return a Server-Sent Event stream given an @IO@ action that+-- is repeatedly called.  An state is threaded for the action so+-- that it may avoid using @IORefs@.  The @IO@ action may sleep+-- or block while waiting for more data.  The HTTP socket is+-- flushed after every list of simultaneous events.  The+-- connection is closed as soon as an 'ES.CloseEvent' is+-- outputted, after which no other events are sent to the client.+ioToRepEventSource :: s+                   -> (EventSourcePolyfill -> s -> IO ([ES.ServerEvent], s))+                   -> GHandler sub master RepEventSource+ioToRepEventSource initial act = do+  polyfill <- prepareForEventSource+  let -- Get new events to be sent.+      getEvents s = do+        (evs, s') <- liftIO (act polyfill s)+        let (builder, continue) = joinEvents evs []+        C.yield (C.Chunk builder)+        C.yield C.Flush+        when continue (getEvents s')++      -- Join all events in a single Builder.  Returns @False@+      -- when we the connection should be closed.+      joinEvents (ev:evs) acc =+        case ES.eventToBuilder ev of+          Just b  -> joinEvents evs (b:acc)+          Nothing -> (fst $ joinEvents [] acc, False)+      joinEvents [] acc = (mconcat (reverse acc), True)++  return $ RepEventSource $ getEvents initial+++-- | Which @EventSource@ polyfill was detected (if any).+data EventSourcePolyfill =+    NoESPolyfill+    -- ^ We didn't detect any @EventSource@ polyfill that we know.+  | Remy'sESPolyfill+    -- ^ See+    -- <https://github.com/remy/polyfills/blob/master/EventSource.js>.+    -- In order to support Remy\'s polyfill, your server needs to+    -- explicitly close the connection from time to+    -- time--browsers such as IE7 will not show any event until+    -- the connection is closed.+    deriving (Eq, Ord, Show, Enum)

+ yesod-eventsource.cabal view

@@ -0,0 +1,42 @@+name:            yesod-eventsource+version:         1.0+license:         MIT+license-file:    LICENSE+author:          Felipe Lessa <felipe.lessa@gmail.com>+maintainer:      Felipe Lessa <felipe.lessa@gmail.com>+synopsis:        Server-sent events support for Yesod apps.+category:        Web, Yesod+stability:       Stable+cabal-version:   >= 1.6+build-type:      Simple+homepage:        http://www.yesodweb.com/+description:+  It's easy to send an event from an HTTP client to a server:+  just send an HTTP request.  However, sending events from the+  server to the client requires more sophisticated approaches.+  Server-sent events (<http://www.w3.org/TR/eventsource/>) are a+  standardized way of pushing events from the server to the+  client.+  .+  This package allows your Yesod application to easily send+  server-sent events.  On the client side, you may use the+  @EventSource@ JavaScript object on browsers that support it+  (https://developer.mozilla.org/en-US/docs/Server-sent_events/EventSource)+  or a polyfill for browsers that don't (we support Remy's+  polyfill out-of-the-box, although that requires you to+  explicitly support it).++library+    build-depends:   base                  >= 4        && < 5+                   , yesod-core            >= 1.1      && < 1.2+                   , conduit               >= 0.5      && < 0.6+                   , wai                   >= 1.3      && < 1.4+                   , wai-eventsource       >= 1.3      && < 1.4+                   , blaze-builder+                   , transformers+    exposed-modules: Yesod.EventSource+    ghc-options:     -Wall++source-repository head+  type:     git+  location: https://github.com/yesodweb/yesod