diff --git a/ChangeLog.md b/ChangeLog.md new file mode 100644 --- /dev/null +++ b/ChangeLog.md @@ -0,0 +1,5 @@ +# Changelog for `streaming-events` + +## 1.0.0 + +- Initial release. diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,30 @@ +Copyright Kadena LLC (c) 2019 + +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following + disclaimer in the documentation and/or other materials provided + with the distribution. + + * Neither the name of Author name here nor the names of other + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/README.md b/README.md new file mode 100644 --- /dev/null +++ b/README.md @@ -0,0 +1,4 @@ +# streaming-events + +Client-side consumption of the `ServerEvent` type from `wai-extra` via the +`streaming` ecosystem. diff --git a/lib/Network/Wai/EventSource/Streaming.hs b/lib/Network/Wai/EventSource/Streaming.hs new file mode 100644 --- /dev/null +++ b/lib/Network/Wai/EventSource/Streaming.hs @@ -0,0 +1,104 @@ +{-# LANGUAGE OverloadedStrings #-} + +-- | +-- Module: Network.Wai.EventSource.Streaming +-- Copyright: Copyright © 2019 Kadena LLC. +-- License: BSD-3-Clause +-- Maintainer: Colin Woodbury +-- +-- Client-side consumption of the `ServerEvent` type from @wai-extra@ via the +-- @streaming@ ecosystem. +-- +module Network.Wai.EventSource.Streaming + ( -- * `ServerEvent` Stream + withEvents + -- * Attoparsec Parser + , event + ) where + +import Control.Applicative (many, optional) +import Control.Monad (unless) +import Data.Attoparsec.ByteString.Char8 +import qualified Data.Attoparsec.ByteString.Streaming as SA +import Data.Binary.Builder (Builder, fromByteString) +import qualified Data.ByteString as B +import qualified Data.ByteString.Streaming.Char8 as SB +import Network.HTTP.Client +import Network.Wai.EventSource (ServerEvent(..)) +import Prelude hiding (takeWhile) +import Streaming +import qualified Streaming.Prelude as SP + +--- + +-- | A low-level wrapper around `withResponse`. Provides a simple, unending +-- source of `ServerEvent`s, presumably from an endpoint served via +-- `Network.Wai.EventSource.eventSourceAppIO` or otherwise. +-- +-- @since 1.0.0 +withEvents :: Request -> Manager -> (Stream (Of ServerEvent) IO () -> IO a) -> IO a +withEvents r m f = withResponse r m $ f . g . responseBody + where + g :: BodyReader -> Stream (Of ServerEvent) IO () + g = void . SA.parsed event . SB.fromChunks . fromBodyReader + +fromBodyReader :: BodyReader -> Stream (Of B.ByteString) IO () +fromBodyReader br = do + bs <- liftIO $ brRead br + unless (B.null bs) $ SP.yield bs >> fromBodyReader br + +-------------------------------------------------------------------------------- +-- Parser + +-- NOTE: This currently ignores: +-- * windows support for now, w.r.t. end-of-line characters +-- * the optional starting byte-order-mark +-- * `CloseEvent` + +{- EXAMPLES + +ServerEvent +----------- +event:New Event +id:id +data:data1 +data:data2 +data:data3 + +CommentEvent +------------ +:this is a comment + +RetryEvent +---------- +retry:100 + +CloseEvent +---------- +No output - the connection is severed. + +-} + +-- | The underlying attoparsec `Parser`. +-- +-- @since 1.0.0 +event :: Parser ServerEvent +event = (sevent <|> comment <|> retry) <* eol + +sevent :: Parser ServerEvent +sevent = ServerEvent + <$> optional (string "event" *> char ':' *> chars <* eol) + <*> optional (string "id" *> char ':' *> chars <* eol) + <*> many (string "data" *> char ':' *> chars <* eol) + +comment :: Parser ServerEvent +comment = CommentEvent <$> (char ':' *> chars <* eol) + +retry :: Parser ServerEvent +retry = RetryEvent <$> (string "retry:" *> decimal <* eol) + +chars :: Parser Builder +chars = fromByteString <$> takeTill (== '\n') + +eol :: Parser Char +eol = char '\n' diff --git a/streaming-events.cabal b/streaming-events.cabal new file mode 100644 --- /dev/null +++ b/streaming-events.cabal @@ -0,0 +1,34 @@ +cabal-version: 2.2 +name: streaming-events +version: 1.0.0 +synopsis: Client-side consumption of a ServerEvent. +description: Client-side consumption of a ServerEvent. +homepage: https://github.com/kadena-io/streaming-events +author: Colin Woodbury +maintainer: colin@kadena.io +copyright: 2019 Kadena LLC +license: BSD-3-Clause +license-file: LICENSE +build-type: Simple +extra-source-files: + README.md + ChangeLog.md + +library + default-language: Haskell2010 + hs-source-dirs: lib + exposed-modules: Network.Wai.EventSource.Streaming + ghc-options: + -Wall -Wcompat -Wpartial-fields -Wincomplete-record-updates + -Wincomplete-uni-patterns -Widentities + + build-depends: + , attoparsec ^>=0.13 + , base >=4.9 && <5 + , binary ^>=0.8 + , bytestring ^>=0.10 + , http-client >= 0.5 && < 0.7 + , streaming ^>=0.2 + , streaming-attoparsec ^>=1.0 + , streaming-bytestring ^>=0.1 + , wai-extra ^>=3.0