Init

.gitignore

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+dist/

LICENSE

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+Copyright (c)2012, Kamil Ciemniewski
+
+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 Kamil Ciemniewski 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.

README.markdown

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+## Snaplet-Environments
+
+Snap Framework ( http://snapframework.com ) support for having different
+configuration environments.
+
+Ex. you can have development database "your_app_dev" and production
+"your_app_prod" and test "your_app_test" and switch between them
+just by running your app in those environments.
+
+Depends on Snap 0.7.* and others
+
+### Overview
+
+This isn't traditional snaplet that adds something to your App state.
+It just base its works on Snap's configuration API giving you a more
+easy to use ways of getting conf values for environment that your app
+is currently running.
+
+Let's say you have defined "development" environment in your _snaplet.cfg_
+Then running app in this env is as simple as:
+
+```
+yourapp @development
+```
+
+### Defining environments
+
+You just have to put your environments group in config file like ex.:
+
+```
+# Your App main configuration file
+
+database-prefix = "yourapp"
+database-address = "localhost"
+
+recaptcha-test-mode = false
+recaptcha-key  = "sdfgsfdgsdfgsdgs"
+
+heist-root = "resources/templates"
+
+mailers-test-mode = false
+
+environments
+{
+  development
+  {
+    database-name = "$(database-prefix)_development"
+  }
+
+  production
+  {
+    database-name = "$(database-prefix)_production"
+  }
+
+  test
+  {
+    database-name = "$(database-prefix)_test"
+    recaptcha-test-mode = true
+    mailers-test-mode = true
+  }
+}
+```
+
+If you don't specify which env to run your app - it'll choose first 
+env declaration for you. In this exaple:
+
+```
+yourapp
+```
+
+Would run yourapp in "development" environment.
+
+### Integration
+
+In Site.hs
+
+```
+-- (...)
+makeSnaplet "app" "An snaplet example application." Nothing $ do
+    heistRoot   <- lookupEnvDefault "heist-root" "resources/templates"
+
+    dbName      <- lookupEnvDefault "database-name"        "yourapp_development"
+    dbAddress   <- lookupEnvDefault "database-address"     "localhost"
+    dbConns     <- lookupEnvDefault "database-connections" 12
+
+    h  <- nestSnaplet "heist" heist $ do
+            heistInit heistRoot
+    m  <- nestSnaplet "mongoDB" mongoDB $
+            mongoDBInit (host dbAddress) dbConns dbName
+
+    --- (...)
+```
+
+The "lookupEnvDefault" helper function reads value from current environment group 
+or if it doesn't have given key - from root of conf file.
+
+```
+lookupEnvDefault :: (Configured a, Monad (m b v), MonadSnaplet m, MonadIO (m b v)) => Name -> a -> m b v a
+```
+
+That's all:)

Setup.hs

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+import Distribution.Simple
+main = defaultMain

snaplet-environments.cabal

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+-- snaplet-environments.cabal auto-generated by cabal init. For
+-- additional options, see
+-- http://www.haskell.org/cabal/release/cabal-latest/doc/users-guide/authors.html#pkg-descr.
+-- The name of the package.
+Name:                snaplet-environments
+
+-- The package version. See the Haskell package versioning policy
+-- (http://www.haskell.org/haskellwiki/Package_versioning_policy) for
+-- standards guiding when and how versions should be incremented.
+Version:             0.1
+
+-- A short (one-line) description of the package.
+Synopsis:            Provides ability to easly read configuration based on given app environment given at command line, envs are defined in app configuration file
+
+-- A longer description of the package.
+-- Description:         
+
+-- The license under which the package is released.
+License:             BSD3
+
+-- The file containing the license text.
+License-file:        LICENSE
+
+-- The package author(s).
+Author:              Kamil Ciemniewski
+
+-- An email address to which users can send suggestions, bug reports,
+-- and patches.
+Maintainer:          ciemniewski.kamil@gmail.com
+
+-- A copyright notice.
+-- Copyright:           
+
+Category:            Web
+
+Build-type:          Simple
+
+-- Extra files to be distributed with the package, such as examples or
+-- a README.
+-- Extra-source-files:  
+
+-- Constraint on the version of Cabal needed to build this package.
+Cabal-version:       >=1.6
+
+
+Library
+  hs-source-dirs: src
+
+  library
+  exposed-modules:  Snap.Snaplet.Environments,
+                    Snap.Snaplet.Environments.Instances
+
+  -- Packages needed in order to build this package.
+  Build-depends:
+    base >= 4 && < 5,
+    snap == 0.7.*,
+    snap-core   == 0.7.*,
+    mtl >= 2 && < 3,
+    configurator == 0.2.0.0,
+    regex-tdfa == 1.1.8,
+    unordered-containers == 0.1.4.3,
+    text >= 0.11 && < 0.12,
+    haskell98 == 1.1.0.1,
+    bson == 0.1.6
+
+  -- Extra tools (e.g. alex, hsc2hs, ...) needed to build the source.
+  -- Build-tools:    
+
+  extensions: 
+      OverloadedStrings
+    , FlexibleInstances
+    , TypeSynonymInstances
+    , MultiParamTypeClasses 
+

src/Snap/Snaplet/Environments.hs

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+module Snap.Snaplet.Environments( module Data.Configurator, lookupEnvDefault, module Snap.Snaplet.Environments.Instances ) where
+
+import           System (getArgs) 
+
+import           Control.Monad.Reader
+
+import           Snap.Snaplet
+import           Data.Configurator
+import           Data.Configurator.Types
+
+import           Snap.Snaplet.Environments.Instances
+
+import qualified Data.Text as T
+import qualified Data.HashMap.Lazy as HM
+import           Data.List (filter, find)
+import           Text.Regex.TDFA
+
+-- | This function takes current env subconfig and at its base
+--   looks up given name
+lookupEnvDefault :: (Configured a, Monad (m b v), MonadSnaplet m, MonadIO (m b v)) => Name -> a -> m b v a
+lookupEnvDefault name def = do
+  mainConf <- getSnapletUserConfig
+  subName <- getNameForCurEnv name mainConf
+  mv <- liftIO $ Data.Configurator.lookup mainConf subName
+  case mv of
+    Nothing -> liftIO $ lookupDefault def mainConf name
+    Just v  -> (liftIO $ putStrLn "Just") >> return v
+
+getNameForCurEnv :: (Monad (m b v), MonadSnaplet m, MonadIO (m b v)) => Name -> Config -> m b v Name
+getNameForCurEnv name cfg = do
+  env <- getCurrentEnv cfg
+  return $ T.pack $ "environments." ++ env ++ "." ++ (T.unpack name)
+
+getCurrentEnv :: (Monad (m b v), MonadSnaplet m, MonadIO (m b v)) => Config -> m b v String
+getCurrentEnv cfg = do
+  mopt <- return . find (\a -> take 1 a == "@") =<< liftIO getArgs
+  case mopt of
+    Nothing  -> do
+      hm <- liftIO $ getMap cfg
+      case filter (\k -> (T.unpack k) =~ ("app.environments." :: String)) $ HM.keys hm of
+        []     -> error "You have to put at least one env definition in your config file."
+        (x:xs) -> return $ T.unpack $ (T.split (== '.') x) !! 2
+    Just opt -> do
+      hm <- liftIO $ getMap cfg
+      case length (filter (\k -> (T.unpack k) =~ ("app.environments." ++ (tail opt))) $ HM.keys hm) > 0 of
+        True  -> return $ tail opt
+        False -> error $ "Given env name: " ++ opt ++ " wasn't found in your config file."

src/Snap/Snaplet/Environments/Instances.hs

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+module Snap.Snaplet.Environments.Instances where
+
+import           Data.Configurator.Types
+import qualified Data.UString as U
+import qualified Data.Text as T
+
+instance Configured U.UString where
+  convert (String t) = Just $ U.u $ T.unpack t
+  convert _ = Nothing