从haskeline中调用网络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),然后使用该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,我以为我会使用haskeline密码不可见.我能够创建一个命令行程序来获取用户提供的值并打印出来,但是如果我调用使用管道的函数,它就永远不会返回.

这是违规代码:

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起"查询WM ..."我不认为http-conduit实际上正在运行.有关如何使这项工作的任何提示？

尼尔,提前谢谢

Answer 1

你声称它可以在 haskeline 之前使用硬编码的用户名、密码、日期。为了帮助调试，您可能无法将导管提升到 InputT 中。下面的操作还失败吗？（我没有编译这个，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"