从haskeline内调用网络IO

Question

我有一个现有的程序，它接受命令行参数(用户名、密码、日期)，然后使用Network.HTTP.Conduit库将一条xml消息发送到服务器。然后我解析结果，做一些工作，并使用blaze-html写出一个文件。

这一切都很好用；但是，我想我应该使用haskeline，这样密码就看不见了。我可以创建一个命令行程序来获取用户提供的值并将它们打印出来，但是如果我调用使用管道的函数，它永远不会返回。

下面是有问题的代码：

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"

function getWMClients函数为：

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，它挂起在“查询WM...”我不认为http-conduit真的在运行。有任何关于如何使其工作的提示吗？

先谢谢你，尼尔

Answer 1

你声称它使用硬编码的用户名，密码，haskeline之前的日期。为了帮助调试，您可能无法将管道提升到InputT中。以下操作仍然失败吗？(这不是我编译的，所以请随意修复语法错误...)

-- 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"