[英]Haskell use Data from POST REQUEST
我想通過POST請求(文本框中的ip)獲取geocodeip.com的正文。
這是我的代碼:
{-# OPTIONS_GHC -Wall #-}
{-# LANGUAGE ForeignFunctionInterface #-}
{-# LANGUAGE OverloadedStrings #-}
module Main where
import Foreign.C.Types
import Foreign.C.String
import Network.HTTP.Conduit
import qualified Data.ByteString.Lazy as L
import qualified Data.ByteString.Char8 as C8
import Text.HTML.TagSoup
getGPS :: String -> IO ()
getGPS ip = do
initReq <- parseUrl "http://www.geocodeip.com/"
let req = (flip urlEncodedBody) initReq $ [("IP", C8.pack ip)]
let res = withManager $ httpLbs req
tags <- fmap parseTags ( (responseBody res))
print tags
--foreign export ccall getGPS :: CString -> IO ()
到目前為止,如果我“完成”他與L.putStr $ responseBody res
一起工作,就可以了,但是如何從中獲得tags
呢?
編譯錯誤:
Couldn't match type ‘Response L.ByteString’ with ‘L.ByteString’
Expected type: Response L.ByteString
Actual type: Response (Response L.ByteString)
In the first argument of ‘responseBody’, namely ‘res’
In the second argument of ‘($)’, namely ‘responseBody res’
Failed, modules loaded: none.
如何解決這種類型錯誤?
看起來您對do-notation和單子/非單子代碼感到困惑。 這是我的寫法。
getGPS :: String -> IO ()
getGPS ip = do
initReq <- parseUrl "http://www.geocodeip.com/"
let req = urlEncodedBody [("IP", C8.pack ip)] initReq
res <- withManager $ httpLbs req
let tags = parseTags (responseBody res)
print tags
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