diff --git a/LICENSE b/LICENSE
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--- /dev/null
+++ b/LICENSE
@@ -0,0 +1,30 @@
+Copyright (c)2012, Haisheng Wu
+
+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 Haisheng Wu 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
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--- /dev/null
+++ b/README.md
@@ -0,0 +1,4 @@
+hoauth2
+=======
+
+haskell oauth 2
diff --git a/Setup.hs b/Setup.hs
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--- /dev/null
+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/hoauth2.cabal b/hoauth2.cabal
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--- /dev/null
+++ b/hoauth2.cabal
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+Name:                hoauth2
+-- (http://www.haskell.org/haskellwiki/Package_versioning_policy)
+Version:             0.1
+
+Synopsis:            hoauth2
+Description:         
+  Haskell OAuth2 authentication.
+  .
+  Tested following services
+  .
+  * google web oauth: <https://developers.google.com/accounts/docs/OAuth2WebServer>
+  .
+  * weibo oauth2: <http://open.weibo.com/wiki/Oauth2>
+
+Homepage:            freizl.github.com
+License:             BSD3
+License-file:        LICENSE
+Author:              Haisheng Wu
+Maintainer:          freizl@gmail.com
+Copyright:           Haisheng,Wu
+Category:            Network
+Build-type:          Simple
+
+-- Extra files to be distributed with the package, such as examples or
+-- a README.
+Extra-source-files:  
+  README.md
+  test/test-google.hs
+  test/test-weibo.hs
+
+Cabal-version:       >=1.6
+
+Source-Repository head
+  Type:     git
+  Location: https://github.com/freizl/hoauth2
+
+Library
+  Ghc-Options:    -Wall  
+  hs-source-dirs: src
+  Exposed-modules:   
+    Network.OAuth2.HTTP.HttpClient
+
+  Build-Depends:
+    base          >= 4      && < 5,
+    http-conduit  >= 1.2.5 ,
+    conduit       >= 0.2,
+    aeson         >= 0.4 ,
+    mtl           >= 1      && < 2.2,
+    bytestring    >= 0.9    && < 0.10,
+    http-types    >= 0.6.8
+
+      
+  -- Modules not exported by this package.
+  -- Other-modules:       
+  
+  -- Extra tools (e.g. alex, hsc2hs, ...) needed to build the source.
+  -- Build-tools:         
+  
diff --git a/src/Network/OAuth2/HTTP/HttpClient.hs b/src/Network/OAuth2/HTTP/HttpClient.hs
new file mode 100644
--- /dev/null
+++ b/src/Network/OAuth2/HTTP/HttpClient.hs
@@ -0,0 +1,100 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE DeriveDataTypeable #-}
+
+{-
+  A simple OAuth2 client.
+-}
+
+module Network.OAuth2.HTTP.HttpClient 
+       ( OAuth2 (..)
+       , AccessToken (..)
+       , authorizationUrl
+       , postAccessToken
+       , signRequest
+       )
+       where
+
+import Control.Monad.Trans.Resource
+import Data.Aeson
+import qualified Data.ByteString.Char8 as BS
+import qualified Data.ByteString.Lazy.Char8 as BSL
+import Data.List
+import Data.Maybe
+import Data.Typeable (Typeable)
+import Network.HTTP.Types (renderSimpleQuery, parseSimpleQuery)
+import qualified Network.HTTP.Types as HT
+import Network.HTTP.Conduit
+import Control.Exception
+import Control.Applicative ((<$>))
+import Control.Monad (mzero)
+
+-- | Query Parameter Representation
+data OAuth2 = OAuth2 { oauthClientId :: BS.ByteString
+                     , oauthClientSecret :: BS.ByteString
+                     , oauthOAuthorizeEndpoint :: BS.ByteString
+                     , oauthAccessTokenEndpoint :: BS.ByteString
+                     , oauthCallback :: Maybe BS.ByteString
+                     , oauthAccessToken :: Maybe BS.ByteString
+                     } deriving (Show, Eq)
+
+data OAuthException = OAuthException String
+                      deriving (Show, Eq, Typeable)
+
+instance Exception OAuthException
+
+-- | The gained Access Token 
+data AccessToken = AccessToken { accessToken :: BS.ByteString } deriving (Show)
+
+instance FromJSON AccessToken where
+    parseJSON (Object o) = AccessToken <$> o .: "access_token"
+    parseJSON _ = mzero
+
+-- | Prepare the authorization URL
+authorizationUrl :: OAuth2 -> BS.ByteString
+authorizationUrl oa = oauthOAuthorizeEndpoint oa `BS.append` queryStr
+  where queryStr = renderSimpleQuery True query
+        query = foldr step [] [ ("client_id", Just $ oauthClientId oa)
+                              , ("response_type", Just "code")
+                              , ("redirect_uri", oauthCallback oa)]
+
+request  :: Control.Monad.Trans.Resource.ResourceIO m =>
+            Request m -> m (Response BSL.ByteString)
+request req = (withManager . httpLbs) (req { checkStatus = \_ _ -> Nothing })
+
+postAccessToken' :: OAuth2 -> BS.ByteString -> Maybe BS.ByteString -> IO BSL.ByteString
+postAccessToken' oa code grant_type = do
+    print url
+    print query
+    rsp <- request req
+    if (HT.statusCode . statusCode) rsp == 200
+        then return $ responseBody rsp
+        else throwIO . OAuthException $ "Gaining access_token failed: " ++ BSL.unpack (responseBody rsp)
+  where
+    req = urlEncodedBody query . fromJust $ parseUrl url
+    url = BS.unpack $ oauthAccessTokenEndpoint oa
+    query = foldr step [] [ ("client_id", Just $ oauthClientId oa)
+                          , ("client_secret", Just $ oauthClientSecret oa)
+                          , ("code", Just code)
+                          , ("redirect_uri", oauthCallback oa)
+                          , ("grant_type", grant_type) ]
+
+
+
+step :: (a, Maybe b) -> [(a, b)] -> [(a, b)]
+step (a, Just b) xs = (a, b):xs
+step _ xs = xs
+
+-- | Request (POST method) access token URL in order to get @AccessToken@.
+postAccessToken :: OAuth2 
+                -> BS.ByteString          -- ^ Authentication code gained after authorization
+                -> IO (Maybe AccessToken)
+postAccessToken oa code = decode <$> postAccessToken' oa code (Just "authorization_code")
+
+-- | 
+signRequest :: OAuth2 -> Request m -> Request m
+signRequest oa req = req { queryString = (renderSimpleQuery False newQuery) }
+  where
+    newQuery = case oauthAccessToken oa of
+                    Just at -> insert ("oauth_token", at) oldQuery
+                    _ -> insert ("client_id", oauthClientId oa) . insert ("client_secret", oauthClientSecret oa) $ oldQuery
+    oldQuery = parseSimpleQuery (queryString req)
diff --git a/test/test-google.hs b/test/test-google.hs
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--- /dev/null
+++ b/test/test-google.hs
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+{-# LANGUAGE OverloadedStrings #-}
+
+{-
+google web oauth: https://developers.google.com/accounts/docs/OAuth2WebServer
+-}
+
+module Main where
+
+import Network.OAuth2.HTTP.HttpClient
+import qualified Data.ByteString.Char8 as BS
+import Network.HTTP.Types (renderSimpleQuery, parseSimpleQuery)
+import GoogleKey
+
+gauth :: OAuth2
+gauth = googleKeys { oauthOAuthorizeEndpoint = "https://accounts.google.com/o/oauth2/auth"
+                   , oauthAccessTokenEndpoint = "https://accounts.google.com/o/oauth2/token" 
+                   , oauthAccessToken = Nothing
+                   }
+
+main :: IO ()
+main = do 
+          print $ (authorizationUrl gauth) `BS.append` "&" `BS.append` googleScopeStr
+          putStr "visit the url and paste code here: "
+          code <- getLine
+          token <- postAccessToken gauth (BS.pack code) 
+          print token
+
+-- | this is special for google.
+googleScopeStr = renderSimpleQuery False [("scope", "https://www.googleapis.com/auth/userinfo.email")]
diff --git a/test/test-weibo.hs b/test/test-weibo.hs
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--- /dev/null
+++ b/test/test-weibo.hs
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+{-# LANGUAGE OverloadedStrings #-}
+
+{-
+
+weibo oauth2: http://open.weibo.com/wiki/Oauth2
+
+This is very trivial testing of the httpclient api.
+1. this case will print out a URL
+2. run the URL in browser and will navigate to weibo auth page
+3. conform the authentication and browser will navigate back to the callback url,
+   which obviously will failed cause there is no local server.
+4. copy the `code` in the callback url and parse into console
+5. this test case will gain access token using the `code` and print it out.
+
+TODO:
+  1. a simple local server in order to make the test automatically.
+-}
+
+module Main where
+
+import Network.OAuth2.HTTP.HttpClient
+import qualified Data.ByteString.Char8 as BS
+import WeiboKey
+
+weibooauth :: OAuth2
+weibooauth = weiboKey { oauthOAuthorizeEndpoint = "https://api.weibo.com/oauth2/authorize"
+                      , oauthAccessTokenEndpoint = "https://api.weibo.com/oauth2/access_token" 
+                      , oauthAccessToken = Nothing
+                      }
+
+main :: IO ()
+main = do 
+          print $ authorizationUrl weibooauth
+          putStr "visit the url and paste code here: "
+          code <- getLine
+          token <- postAccessToken weibooauth (BS.pack code) 
+          print token