如何将 mongodb 添加到 Snap 应用程序？

Question

鉴于此：

main :: IO ()
main = do
    (conf, site, cleanup) <- $(loadSnapTH [| getConf |]
                                          'getActions
                                          ["snaplets/heist/templates"])


    _ <- try $ httpServe conf site :: IO (Either SomeException ())
    cleanup


------------------------------------------------------------------------------
-- | This action loads the config used by this application. The loaded config
-- is returned as the first element of the tuple produced by the loadSnapTH
-- Splice. The type is not solidly fixed, though it must be an IO action that
-- produces the same type as 'getActions' takes. It also must be an instance of
-- Typeable. If the type of this is changed, a full recompile will be needed to
-- pick up the change, even in development mode.
--
-- This action is only run once, regardless of whether development or
-- production mode is in use.
getConf :: IO (Config Snap AppConfig)
getConf = commandLineConfig defaultConfig


------------------------------------------------------------------------------
-- | This function generates the the site handler and cleanup action from the
-- configuration. In production mode, this action is only run once. In
-- development mode, this action is run whenever the application is reloaded.
--
-- Development mode also makes sure that the cleanup actions are run
-- appropriately before shutdown. The cleanup action returned from loadSnapTH
-- should still be used after the server has stopped handling requests, as the
-- cleanup actions are only automatically run when a reload is triggered.
--
-- This sample doesn't actually use the config passed in, but more
-- sophisticated code might.
getActions :: Config Snap AppConfig -> IO (Snap (), IO ())
getActions conf = do
    (msgs, site, cleanup) <- runSnaplet
        (appEnvironment =<< getOther conf) app
    hPutStrLn stderr $ T.unpack msgs
    return (site, cleanup)

如果我想添加 mongodb 数据库功能，我什至应该在哪里开始 (this nice example here)???

Snap 只有两个例子：

1. 一个非常简单的（在这里没用）：http://snapframework.com/docs/tutorials/snap-api
2. 还有上面那个，是用 snap 生成的（我已经忘了我是怎么生成的了，在文档里好像找不到？）

Answer 1

你可以使用包snaplet-mongodb-minimalistic，github上有example的用法。