Question

我试图找到一种方法来检查Haskell中是否存在网页。服务器只是HTTP2 / HTTPS，我试图检查该服务器应用程序中是否存在该页面。

是否有任何带有良好文档的Haskell软件包只是检查状态代码是200还是404？并使用强大的HTTPS和HTTP2服务器？

这里我目前使用http-conduit，但我收到了奇怪的异常（TlsExceptionHostPort（HandshakeFailed（Error_Protocol（＆＃34;期待服务器问候，得到警报：[（AlertLevel_Fatal，HandshakeFailure）]＆＃34; ，True，HandshakeFailure）））＆＃34; thibaud.dauce.fr＆＃34; 443和StatusCodeException）。

... other imports
import qualified Network.HTTP.Conduit as HTTP

... other types
type AppM = ReaderT Config (EitherT ServantErr IO)

newComment :: String -> OneComment -> AppM Int64
newComment baseUrl oneComment = do
    time <- liftIO getCurrentTime
    response <- HTTP.withManager $ \manager -> do
        request <- HTTP.parseUrl $ url oneComment
        HTTP.httpLbs request manager
    case (statusIsSuccessful $ HTTP.responseStatus response, startswith baseUrl (url oneComment)) of
        (_, False) -> return 0
        (True, True) -> do
            theNewComment <- runDb $ insert $ Comment (url oneComment) (content oneComment) time
            return $ fromSqlKey theNewComment
        _ -> return 0

Answer 1

使用wreq

的一些示例

{-# LANGUAGE OverloadedStrings #-}

import Network.Wreq
import Control.Lens
import Control.Exception as E
import Network.HTTP.Client (HttpException)

test1 = do
  r <- get "https://httpbin.org/get"
  print $ r ^. responseStatus . statusCode

-- throws an exception
test2 = do
  r <- get "https://www.google123123.com"
  print $ r ^. responseStatus . statusCode

testUrl url = do
  r <- get url
  return $ r ^. responseStatus . statusCode

-- catching the exception
test3 = do
  st <- testUrl "https://www.google123123123.com"  `E.catch` handler
  print st
  where
    handler :: HttpException -> IO Int
    handler _ = return 999

获取Haskell中网页的状态代码

1 个答案: