Question

我想再谈谈IHttpActionResult和HttpResponseMessage的不同之处。我知道IHttpActionResult更灵活，更适合单元测试。但目前我正在处理从WebAPI迁移到WebAPi 2的项目，我想尝试将HttpResponseMessage的所有使用替换为IHttpActionResult。我在代码中找到了下一行：

catch (Exception ex)
{
    return Request.CreateErrorResponse(HttpStatusCode.InternalServerError, ex.Message);
}

我想澄清一下IHttpActionResult的等效方法。以下代码中的结果是否等同于上面代码中的结果：

catch (Exception ex)
{
    return Content(HttpStatusCode.InternalServerError, ex.Message);
}

或者我应该使用其他东西吗？

Answer 1

理想情况下，您应该将其包装在ResponseMessage中 - 帮助Content Negotiation：

catch (Exception ex)
{
    return ResponseMessage(Request.CreateErrorResponse(HttpStatusCode.InternalServerError, ex.Message));
}

Answer 2

如果您使用IHttpActionResult

data ClientDisappeared = ClientDisappeared deriving (Show, Eq, Enum, Ord)
instance Exception ClientDisappeared

runSettingsSignalDisconnect :: Warp.Settings -> Wai.Application -> IO ()
runSettingsSignalDisconnect set =
  runSettings' set (WarpI.socketConnection >=> return . wrapConn)
  where
    -- Fork a 'monitor' thread that does nothing but attempt to
    -- perform a read from conn in a loop 1/sec, and wrap the receive
    -- methods on conn so that they first consume from the stuff read
    -- by the monitoring thread. If the monitoring thread sees
    -- end-of-file (signaled by an empty string read), raise
    -- ClientDisappered on the per-connection thread.
    wrapConn conn = do
      tid <- myThreadId
      nxtBstr <- newEmptyMVar :: IO (MVar ByteString)
      semaphore <- newMVar ()
      readerCount <- newIORef (0 :: Int)
      monitorThread <- forkIO (monitor tid nxtBstr semaphore readerCount)
      return $ conn {
        WarpI.connClose = throwTo monitorThread ClientDisappeared
                          >> WarpI.connClose conn
        , WarpI.connRecv = newRecv nxtBstr semaphore readerCount
        , WarpI.connRecvBuf = newRecvBuf nxtBstr semaphore readerCount
        }
      where
        newRecv :: MVar ByteString -> MVar () -> IORef Int
                -> IO ByteString
        newRecv nxtBstr sem readerCount =
          bracket_
          (atomicModifyIORef' readerCount $ \x -> (succ x, ()))
          (atomicModifyIORef' readerCount $ \x -> (pred x, ()))
          (withMVar sem $ \_ -> do w <- tryTakeMVar nxtBstr
                                   case w of
                                     Just w' -> return w'
                                     Nothing -> WarpI.connRecv conn
          )

        newRecvBuf :: MVar ByteString -> MVar () -> IORef Int
                   -> WarpI.Buffer -> WarpI.BufSize -> IO Bool
        newRecvBuf nxtBstr sem readerCount buf bufSize =
          bracket_
          (atomicModifyIORef' readerCount $ \x -> (succ x, ()))
          (atomicModifyIORef' readerCount $ \x -> (pred x, ()))
          (withMVar sem $ \_ -> do
              (fulfilled, buf', bufSize') <-
                if bufSize == 0 then return (False, buf, bufSize)
                else
                  do w <- tryTakeMVar nxtBstr
                     case w of
                       Nothing -> return (False, buf, bufSize)
                       Just w' -> do
                         let wlen = B.length w'
                         if wlen > bufSize
                           then do BU.unsafeUseAsCString w' $ \cw' ->
                                     copyBytes buf (castPtr cw') bufSize
                                   putMVar nxtBstr (B.drop bufSize w')
                                   return (True, buf, 0)
                           else do BU.unsafeUseAsCString w' $ \cw' ->
                                     copyBytes buf (castPtr cw') wlen
                                   return (wlen == bufSize, plusPtr buf wlen,
                                           bufSize - wlen)
              if fulfilled then return True
                else WarpI.connRecvBuf conn buf' bufSize'
          )
        dropClientDisappeared :: ClientDisappeared -> IO ()
        dropClientDisappeared _ = return ()
        monitor tid nxtBstr sem st =
          catch (monitor' tid nxtBstr sem st) dropClientDisappeared

        monitor' tid nxtBstr sem st = do
          (hitEOF, readerCount) <- withMVar sem $ \_ -> do
            w <- tryTakeMVar nxtBstr
            case w of
              -- No one picked up our bytestring from last time
              Just w' -> putMVar nxtBstr w' >> return (False, 0)
              Nothing -> do
                w <- WarpI.connRecv conn
                putMVar nxtBstr w
                readerCount <- readIORef st
                return (B.null w, readerCount)
          if hitEOF && (readerCount == 0)
            -- Don't signal if main thread is also trying to read -
            -- in that case, main thread will see EOF directly
            then throwTo tid ClientDisappeared
            else do threadDelay oneSecondInMicros
                    monitor' tid nxtBstr sem st
        oneSecondInMicros = 1000000

IHttpActionResult vs HttpResponseMessage

2 个答案: