Question

我试图使用函数postBody

postBody :: (Yesod site, RedirectUrl site url) => url -> ByteString -> YesodExample site ()

来自Yesod.Test包的

。文档说它可以像这样使用

import Data.Aeson
postBody HomeR (encode $ object ["age" .= (1 :: Integer)])

但是，当我尝试在我的应用中使用它时

    describe "Posts" $ do
        it "posts post and returns post" $ do
            postBody PostR (encode $ object [
                "body" .= ("test post" :: Text),
                "title" .= ("test post" :: Text),
                "coverImage" .= ("test post" :: Text),
                "author" .= (0 :: Int)
                ])
            statusIs 200

我收到了错误

• Couldn't match expected type ‘Post’ with actual type ‘Route App’
• In the first argument of ‘postBody’, namely ‘PostR’
  In a stmt of a 'do' block:
    postBody
      PostR
      (encode
       $ object
           ["body" .= ("test post" :: Text), "title" .= ("test post" :: Text),

            "coverImage" .= ("test post" :: Text), "author" .= (0 :: Int)])
  In the second argument of ‘($)’, namely
    ‘do { postBody
            PostR
            (encode
             $ object
                 ["body" .= ("test post" :: Text), "title" .= ("test post" :: Text),
                  ....]);
          statusIs 200 }’

我的用法似乎与示例相同，所以我无法理解它为什么会失败。

PostR在此处的路线文件中

/posts PostR POST

及其处理程序

postPostR :: Handler Value
postPostR = do
    post <- requireJsonBody :: Handler Post
    maybeUserID <- maybeAuthId
    case maybeUserID of
        Just userID -> do
            let post' = post {postAuthor = userID}
            inserted <- runDB $ insertEntity post'
            returnJson inserted
        Nothing -> sendResponseStatus status403 ("Unauthorized" :: Text)

Answer 1

问题最终是在posts表中有一个列体，所以Yesod为此创建了postBody，它与Yesod.Test中的postBody冲突。

解决方案是在yesod测试中使用限定导入

import qualified Yesod.Test as T

无法将预期类型“发布”与实际类型“路线应用”匹配

1 个答案: