从哈斯克林内部调用网络 IO

Question

我有一个现有的程序，它采用命令行参数（用户名，密码，日期），然后使用Network.HTTP.Conduit库将xml消息发布到服务器。然后我解析结果，做一些工作并使用blaze-html写出文件。

这一切都像一个魅力; 但是，我想我会使用haskeline这样密码就不可见了。我能够创建一个命令行程序来获取用户提供的值并将其打印出来，但是如果我调用使用 conduit 的函数，它永远不会返回。

这是有问题的代码：

main = runInputT defaultSettings loop
where 
    loop :: InputT IO ()
    loop = do
        Just username <- getInputLine "WM username: "
        Just password <- getPassword (Just '*') "WM password: "
        Just date     <- getInputLine "Date (YYYYMMDD): "
        outputStrLn "querying WM..."
        clients <- lift $ getWMClients username password
        outputStrLn "successfully retrieved client list from WM..."
        let outHeader = renderHeader date username
        reportString <- mapM  (x -> createString x clients)  cList
        lift $ writeFile (date ++ "_report.html") (outHeader ++ concat reportString)
        outputStrLn "Done"

函数getWMClients函数是：

getWMClients :: Username -> String -> IO [Client]
getWMClients username password = do
    let f = [Size "-1", Skip "0"]
    let fs = [Select "id",
              Select "status",
              Select "last-name",
              Select "first-name",
             ]
    let query = WMQuery {transaction=SHARE,service=Query,businessObject=CONT,field=f,fields=fs}
    results <- doQuery username (Just password) Nothing (Just query)
    rows <- xmlResultsToMaps results
    let clients = map makeClient rows
    return clients

当我运行该程序时，它挂在"查询 WM..."我不认为http-conduit实际上正在运行。关于如何使这项工作的任何提示？

提前感谢，尼尔

Answer 1

您声称它适用于硬编码的用户名，密码，haskeline之前的日期。 为了帮助调试，也许您无法将管道提升到 InputT 中。 以下仍然失败吗？ （我没有编译这个，所以请随时修复语法错误...

-- Isolate the haskeline monad to just the input part:
main = loop
where 
    loop :: IO ()
    loop = do
      (username,password,date) <- runInputT defaultSettings $ do
        Just username <- getInputLine "WM username: "
        Just password <- getPassword (Just '*') "WM password: "
        Just date     <- getInputLine "Date (YYYYMMDD): "
        return (username,password,date)
      putStrLn "querying WM..."
      clients <- getWMClients username password
      putStrLn "successfully retrieved client list from WM..."
      let outHeader = renderHeader date username
      putString <- mapM  (x -> createString x clients)  cList
      writeFile (date ++ "_report.html") (outHeader ++ concat reportString)
      putStrLn "Done"