initial import

.gitignore

@@ -1,5 +1,6 @@
 dist
 cabal-dev
+tags
 *.o
 *.hi
 *.chi

active-cache-wai/LICENSE

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+Copyright (c) 2012, yihuang
+
+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 yihuang 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.

active-cache-wai/README.rst

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+This service 

active-cache-wai/Setup.hs

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+import Distribution.Simple
+main = defaultMain

active-cache-wai/Simple.hs

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+import Network.Wai
+import Network.Wai.Handler.Warp (run)
+import qualified Network.HTTP.Conduit as HTTP
+import Network.HTTP.Types
+import Data.Monoid
+import qualified Blaze.ByteString.Builder as B
+import qualified Data.ByteString.Lazy as L
+import Control.Concurrent
+import Control.Exception
+import Control.Monad
+import Control.Monad.IO.Class (liftIO)
+
+type SimpleState = L.ByteString
+
+-- handle http requests
+app :: MVar SimpleState -> Application
+app state req = case pathInfo req of
+    [] -> do
+        d <- liftIO (takeMVar state)
+        return $ response d
+    _ -> return response404
+  where
+    response = ResponseBuilder status200 [] . B.fromLazyByteString
+    response404 = ResponseBuilder status404 [] mempty
+
+-- update the cache periodically.
+cacher :: String -> MVar SimpleState -> Int -> IO ()
+cacher url state interval = forever $ do
+    ersp <- try (HTTP.simpleHttp url)
+    case ersp of
+        Right rsp -> void $ swapMVar state rsp
+        Left err -> print (err::SomeException)
+    threadDelay interval
+
+main :: IO ()
+main = do
+    let port = 3000
+    state <- newEmptyMVar :: IO (MVar SimpleState)
+    _ <- forkIO (cacher "http://10.10.10.3:9002/" state 1000)
+    putStrLn $ "http://localhost:"++show port
+    run port (app state)

active-cache-wai/StructuredState.hs

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+{-# LANGUAGE DeriveGeneric #-}
+import Network.Wai
+import Network.Wai.Handler.Warp (run)
+import qualified Network.HTTP.Conduit as HTTP
+import Network.HTTP.Types
+import GHC.Generics
+import Data.Monoid
+import Data.Aeson
+import Data.Aeson.Types (typeMismatch)
+import qualified Data.Vector as V
+import qualified Blaze.ByteString.Builder as B
+import Control.Concurrent
+import Control.Exception
+import Control.Monad
+import Control.Monad.IO.Class (liftIO)
+
+newtype SimpleState = SimpleState Int
+    deriving (Generic)
+
+instance ToJSON SimpleState
+instance FromJSON SimpleState where
+    parseJSON (Array vec) = return $ SimpleState $ V.length vec
+    parseJSON o = typeMismatch "SimpleState" o
+
+-- handle http requests
+app :: MVar SimpleState -> Application
+app state req = case pathInfo req of
+    [] -> do
+        d <- liftIO (takeMVar state)
+        return $ response (encode d)
+    _ -> return response404
+  where
+    response = ResponseBuilder status200 [] . B.fromLazyByteString
+    response404 = ResponseBuilder status404 [] mempty
+
+-- update the cache periodically.
+cacher :: String -> MVar SimpleState -> Int -> IO ()
+cacher url state interval = forever $ do
+    ersp <- try (HTTP.simpleHttp url)
+    case ersp of
+        Right rsp -> maybe (putStrLn "decode json failed.")
+                           (void . swapMVar state)
+                           (decode rsp)
+        Left err -> print (err::SomeException)
+    threadDelay interval
+
+main :: IO ()
+main = do
+    let port = 3000
+    state <- newEmptyMVar :: IO (MVar SimpleState)
+    _ <- forkIO (cacher "http://10.10.10.3:9002/" state 1000)
+    putStrLn $ "http://localhost:"++show port
+    run port (app state)

active-cache-wai/active-cache-wai.cabal

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+-- Initial active-cache-wai.cabal generated by cabal init. For further
+-- documentation, see http://haskell.org/cabal/users-guide/
+
+name:                active-cache-wai
+version:             0.1.0.0
+synopsis:            a cache service that update actively.
+-- description:         
+license:             BSD3
+license-file:        LICENSE
+author:              yihuang
+maintainer:          yi.codeplayer@gmail.com
+-- copyright:           
+category:            Web
+build-type:          Simple
+cabal-version:       >=1.8
+
+executable active-cache-wai-Simple
+  main-is:             Simple.hs
+  build-depends:       base ==4.5.*, wai ==1.1.*, warp ==1.1.*, http-conduit ==1.2.*, http-types ==0.6.*, ghc-prim ==0.2.*, aeson ==0.6.*, vector ==0.9.*, blaze-builder ==0.3.*, transformers ==0.2.*, bytestring ==0.9.*
+
+executable active-cache-wai-StructuredState
+  main-is:             StructuredState.hs
+  build-depends:       base ==4.5.*, wai ==1.1.*, warp ==1.1.*, http-conduit ==1.2.*, http-types ==0.6.*, ghc-prim ==0.2.*, aeson ==0.6.*, vector ==0.9.*, blaze-builder ==0.3.*, transformers ==0.2.*, bytestring ==0.9.*

active-cache-wai/diff.patch

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+0a1
+> {-# LANGUAGE DeriveGeneric #-}
+4a6
+> import GHC.Generics
+5a8,10
+> import Data.Aeson
+> import Data.Aeson.Types (typeMismatch)
+> import qualified Data.Vector as V
+7d11
+< import qualified Data.ByteString.Lazy as L
+13c17,23
+< type SimpleState = L.ByteString
+---
+> newtype SimpleState = SimpleState Int
+>     deriving (Generic)
+> 
+> instance ToJSON SimpleState
+> instance FromJSON SimpleState where
+>     parseJSON (Array vec) = return $ SimpleState $ V.length vec
+>     parseJSON o = typeMismatch "SimpleState" o
+20c30
+<         return $ response d
+---
+>         return $ response (encode d)
+31c41,43
+<         Right rsp -> void $ swapMVar state rsp
+---
+>         Right rsp -> maybe (putStrLn "decode json failed.")
+>                            (void . swapMVar state)
+>                            (decode rsp)