如何使用Snap Framework维护服务器端状态？ [英] How do I maintain a server-side state with Snap Framework?

问题描述

服务器端会话还不是Snap Framework的一部分。有没有办法添加某种服务器端状态？

假设我想为每个HTTP请求增加一个计数器。我会怎么做？

解决方案

最简单的方法是将状态置于mvar后面：

  fooHandler :: MVar Int  - > Snap（）
 fooHandler mvar = do 
 x<  -  liftIO $ modifyMVar mvar $ \y  - >让y'= y + 1 in（y'，y'）
 writeBS $ S.pack $将计数器增加到：++ show x 
  

在网站初始化时初始化mvar。希望这有助于。

Server-side sessions are not [yet] part of the Snap Framework. Is there a way to add some sort of server side state?

Let's pretend I want to increment a counter for each HTTP request. How would I do it?

解决方案

Easiest way is to put the state behind an mvar:

fooHandler :: MVar Int -> Snap ()
fooHandler mvar = do
    x <- liftIO $ modifyMVar mvar $ \y -> let y'=y+1 in (y',y')
    writeBS $ S.pack $ "Incremented counter to: " ++ show x

Initialize the mvar when the site is initialized. Hope this helps.

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