wai-middleware-caching (empty) → 0.1.0.0

raw patch · 5 files changed

+202/−0 lines, 5 filesdep +basedep +blaze-builderdep +bytestringsetup-changed

Dependencies added: base, blaze-builder, bytestring, wai, wai-middleware-caching

Files

• LICENSE +30/−0
• Setup.hs +2/−0
• src/Network/Wai/Middleware/Cache.hs +132/−0
• test/Spec.hs +2/−0
• wai-middleware-caching.cabal +36/−0

@@ -0,0 +1,30 @@+Copyright Yann Esposito (c) 2015++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.

@@ -0,0 +1,2 @@+import Distribution.Simple+main = defaultMain

@@ -0,0 +1,132 @@+{-# LANGUAGE OverloadedStrings #-}+module Network.Wai.Middleware.Cache+  ( cache+  , cacheNoBody+  , CacheBackend(..)+  , responseToLBS+  ) where++import           Blaze.ByteString.Builder (Builder, toLazyByteString)+import           Data.ByteString          (ByteString)+import qualified Data.ByteString.Char8    as S8+import qualified Data.ByteString.Lazy     as LZ+import           Data.IORef+import           Network.Wai              (Middleware, Request, Response,+                                           requestBody, responseToStream,+                                           mapResponseHeaders)++--------------------------------------------------------------------------------+-- | The data structure that should contains everything you need to create+-- a cache backend+data CacheBackend cacheContainer cacheKey cacheVal =+  CacheBackend {+  keyFromReq           :: Request -> ByteString -> IO cacheKey -- ^ Get cacheKey from request and its body+  , toCache            :: Request -> ByteString -> IO Bool -- ^ Function to check whether cache or not+  , addToCache         :: cacheContainer -> cacheKey -> cacheVal -> IO () -- ^ Adding to cache+  , actionOnCache      :: Request -> Response -> IO () -- ^ Action to perform before each caching request+  , actionOnCacheMiss  :: Request -> Response -> IO () -- ^ Action to perfom before each cache miss+  , responseToCacheVal :: Response -> IO cacheVal -- ^ Transform response to cached value+  , cacheValToResponse :: cacheVal -> Response -- ^ Transform cached value to response+  , lookupCache        :: cacheContainer -> cacheKey -> IO (Maybe cacheVal) -- ^ cache lookup+  , cacheContainer     :: cacheContainer -- ^ A cache container+  }++--------------------------------------------------------------------------------+-- Cache Backend Agnostic Cache Middleware+-- This version duplicate the body of the request making it quite far less efficient+-- than the cacheNoBody function+cache :: CacheBackend cc ck cv -- ^ A cache backend+      -> Middleware+cache cb app req sendResponse = do+  (req',body) <- getRequestBody req+  caching <- toCache cb req' body+  if not caching+     then app req' sendResponse+     else do+       (req'',_) <- getRequestBody req'+       cacheKey <- keyFromReq cb req'' body+       found <- lookupCache cb (cacheContainer cb) cacheKey+       maybe (app req'' (addToCacheAndRespond cb sendResponse req cacheKey))+         (respondFromCache cb sendResponse req'')+         found++--------------------------------------------------------------------------------+-- Cache Backend Agnostic Cache Middleware+-- This version don't provide the request body for create key or deciding+-- whether to cache. But it should be more efficient+cacheNoBody :: CacheBackend cc ck cv -- ^ A cache backend+               -> Middleware+cacheNoBody cb app req sendResponse = do+  caching <- toCache cb req S8.empty+  if not caching+     then app req sendResponse+     else do+       cacheKey <- keyFromReq cb req S8.empty+       found <- lookupCache cb (cacheContainer cb) cacheKey+       maybe (app req (addToCacheAndRespond cb sendResponse req cacheKey))+         (respondFromCache cb sendResponse req)+         found++addXCacheHeader :: Response -> Response+addXCacheHeader = mapResponseHeaders (("X-Cached","true"):)++respondFromCache :: CacheBackend cc ck cv+                 -> (Response -> IO b)+                 -> Request+                 -> cv+                 -> IO b+respondFromCache cb sendResponse r cachedVal = do+  let response = cacheValToResponse cb cachedVal+  actionOnCache cb r response+  sendResponse (addXCacheHeader response)++addToCacheAndRespond :: CacheBackend cc ck cv+                     -> (Response -> IO b)+                     -> Request+                     -> ck+                     -> Response+                     -> IO b+addToCacheAndRespond cb sendResponse req key r = do+  cacheVal <- responseToCacheVal cb r+  addToCache cb (cacheContainer cb) key cacheVal+  actionOnCacheMiss cb req r+  sendResponse (cacheValToResponse cb cacheVal)++getRequestBody :: Request -> IO (Request, S8.ByteString)+getRequestBody req = do+  let loop front = do+         bs <- requestBody req+         if S8.null bs+             then return $ front []+             else loop $ front . (bs:)+  body <- loop id+  -- logging the body here consumes it, so fill it back up+  -- obviously not efficient+  --+  -- Note: previously, we simply used CL.sourceList. However,+  -- that meant that you could read the request body in twice.+  -- While that in itself is not a problem, the issue is that,+  -- in production, you wouldn't be able to do this, and+  -- therefore some bugs wouldn't show up during testing. This+  -- implementation ensures that each chunk is only returned+  -- once.+  ichunks <- newIORef body+  let rbody = atomicModifyIORef ichunks $ \chunks ->+         case chunks of+             [] -> ([], S8.empty)+             x:y -> (y, x)+  let req' = req { requestBody = rbody }+  return (req', S8.concat body)++-- | Helper for your cache backend+responseToLBS :: Response -> IO LZ.ByteString+responseToLBS response = do+  let (_,_,f) = responseToStream response+  f $ \streamingBody -> do+    builderRef <- newIORef mempty+    let add :: Builder -> IO ()+        add b = atomicModifyIORef builderRef $ \builder -> (builder `mappend` b,())+        flush :: IO ()+        flush = return ()+    streamingBody add flush+    fmap toLazyByteString (readIORef builderRef)

@@ -0,0 +1,2 @@+main :: IO ()+main = putStrLn "Test suite not yet implemented"

@@ -0,0 +1,36 @@+name:                wai-middleware-caching+version:             0.1.0.0+synopsis:            WAI Middleware to cache things+description:         Please see README.md+homepage:            http://github.com/yogsototh/wai-middleware-caching/tree/master/wai-middleware-caching#readme+license:             BSD3+license-file:        LICENSE+author:              Yann Esposito+maintainer:          yann.esposito@gmail.com+copyright:           2015 Yann Esposito+category:            Web+build-type:          Simple+-- extra-source-files:+cabal-version:       >=1.10++library+  hs-source-dirs:      src+  exposed-modules:     Network.Wai.Middleware.Cache+  build-depends:       base >= 4.7 && < 5+                     , blaze-builder+                     , bytestring+                     , wai+  default-language:    Haskell2010++test-suite wai-middleware-caching-test+  type:                exitcode-stdio-1.0+  hs-source-dirs:      test+  main-is:             Spec.hs+  build-depends:       base+                     , wai-middleware-caching+  ghc-options:         -threaded -rtsopts -with-rtsopts=-N+  default-language:    Haskell2010++source-repository head+  type:     git+  location: https://github.com/yogsototh/wai-middleware-caching