Question

我试图找出如何使用haskell / yesod实现基本auth，这是一个有效的基本实现，从类似的问题中引用。

module Handler.BasicAuth where

import Import
import Network.Wai 
import Network.HTTP.Types as Import
    ( status200 )

httpBasicAuth :: Handler ()
{-getBasicAuthR = error "Not yet implemented: getBasicAuthR"-}
httpBasicAuth = do
    request <- waiRequest
    case lookup "Authorization" (requestHeaders request) of 
        Just "Basic base64encodedusernameandpassword" -> return ()
        _ -> do
            addHeader "WWW-Authenticate" "Basic Realm=\"My Realm\""
            permissionDenied "Authentication required"

getBasicAuthR :: Handler ()
getBasicAuthR = httpBasicAuth >>
    sendResponseStatus status200 ()

我想修改我的实现，不仅返回http响应代码200，还返回读取{"hello": "world"}的自定义JSON。

我怎样才能做到这一点？

修改

正如以下各方所建议的那样，我应该将getBasicAuthR写为

getBasicAuthR :: Handler Value
getBasicAuthR = httpBasicAuth >> sendResponse $ object ["hello" .= "world"]

但这只是给我一个错误，说

Handler/BasicAuth.hs:27:17:
    Couldn't match expected type ‘Value -> Handler Value’
                with actual type ‘HandlerT App IO b0’
    The first argument of ($) takes one argument,
    but its type ‘HandlerT App IO b0’ has none
    In the expression:
      httpBasicAuth >> sendResponse $ object ["hello" .= "world"]
    In an equation for ‘getBasicAuthR’:
        getBasicAuthR
          = httpBasicAuth >> sendResponse $ object ["hello" .= "world"]

Handler/BasicAuth.hs:27:34:
    Couldn't match expected type ‘HandlerT App IO b0’
                with actual type ‘c0 -> m0 a0’
    Probable cause: ‘sendResponse’ is applied to too few arguments
    In the second argument of ‘(>>)’, namely ‘sendResponse’
    In the expression: httpBasicAuth >> sendResponse

Answer 1

首先，如果您想要使用JSON对象进行响应，则可以更改处理程序的类型。由于yesod-core使用aeson，因此相应的类型为Handler Value：

getBasicAuthR :: Handler Value

由于monad法律，httpBasicAuth >>会停留，但后跟sendResponse（或sendResponseStatus 200）并附加一个对象：

getBasicAuthR = httpBasicAuth >> sendResponse (object ["hello" .= "world"])

Answer 2

这个答案取自Zeta的评论：

getBasicAuthR :: Handler JSON
getBasicAuthR = httpBasicAuth >> sendResponse (object ["hello" .= "world])

如何修改我的代码以返回自定义JSON而不仅仅是状态200？

2 个答案: