mongodb/Database/MongoDB/Internal/Network.hs

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-- | Compatibility layer for network package, including newtype 'PortID'
{-# LANGUAGE CPP, OverloadedStrings #-}
module Database.MongoDB.Internal.Network (Host(..), PortID(..), N.HostName, connectTo,
lookupReplicaSetName, lookupSeedList) where
#if !MIN_VERSION_network(2, 9, 0)
import qualified Network as N
import System.IO (Handle)
#else
import Control.Exception (bracketOnError)
import Network.BSD as BSD
import qualified Network.Socket as N
import System.IO (Handle, IOMode(ReadWriteMode))
#endif
import Data.ByteString.Char8 (pack, unpack)
import Data.List (dropWhileEnd)
import Data.Maybe (fromMaybe)
import Data.Text (Text)
import Network.DNS.Lookup (lookupSRV, lookupTXT)
import Network.DNS.Resolver (defaultResolvConf, makeResolvSeed, withResolver)
import Network.HTTP.Types.URI (parseQueryText)
-- | Wraps network's 'PortNumber'
-- Used to ease compatibility between older and newer network versions.
data PortID = PortNumber N.PortNumber
#if !defined(mingw32_HOST_OS) && !defined(cygwin32_HOST_OS) && !defined(_WIN32)
| UnixSocket String
#endif
deriving (Eq, Ord, Show)
#if !MIN_VERSION_network(2, 9, 0)
-- Unwrap our newtype and use network's PortID and connectTo
connectTo :: N.HostName -- Hostname
-> PortID -- Port Identifier
-> IO Handle -- Connected Socket
connectTo hostname (PortNumber port) = N.connectTo hostname (N.PortNumber port)
#if !defined(mingw32_HOST_OS) && !defined(cygwin32_HOST_OS) && !defined(_WIN32)
connectTo _ (UnixSocket path) = N.connectTo "" (N.UnixSocket path)
#endif
#else
-- Copied implementation from network 2.8's 'connectTo', but using our 'PortID' newtype.
-- https://github.com/haskell/network/blob/e73f0b96c9da924fe83f3c73488f7e69f712755f/Network.hs#L120-L129
connectTo :: N.HostName -- Hostname
-> PortID -- Port Identifier
-> IO Handle -- Connected Socket
connectTo hostname (PortNumber port) = do
proto <- BSD.getProtocolNumber "tcp"
bracketOnError
(N.socket N.AF_INET N.Stream proto)
N.close -- only done if there's an error
(\sock -> do
he <- BSD.getHostByName hostname
N.connect sock (N.SockAddrInet port (hostAddress he))
N.socketToHandle sock ReadWriteMode
)
#if !defined(mingw32_HOST_OS) && !defined(cygwin32_HOST_OS) && !defined(_WIN32)
connectTo _ (UnixSocket path) = do
bracketOnError
(N.socket N.AF_UNIX N.Stream 0)
N.close
(\sock -> do
N.connect sock (N.SockAddrUnix path)
N.socketToHandle sock ReadWriteMode
)
#endif
#endif
-- * Host
data Host = Host N.HostName PortID deriving (Show, Eq, Ord)
lookupReplicaSetName :: N.HostName -> IO (Maybe Text)
-- ^ Retrieves the replica set name from the TXT DNS record for the given hostname
lookupReplicaSetName hostname = do
rs <- makeResolvSeed defaultResolvConf
res <- withResolver rs $ \resolver -> lookupTXT resolver (pack hostname)
case res of
Left _ -> pure Nothing
Right [] -> pure Nothing
Right (x:_) ->
pure $ fromMaybe (Nothing :: Maybe Text) (lookup "replicaSet" $ parseQueryText x)
lookupSeedList :: N.HostName -> IO [Host]
-- ^ Retrieves the replica set seed list from the SRV DNS record for the given hostname
lookupSeedList hostname = do
rs <- makeResolvSeed defaultResolvConf
2020-01-02 01:38:13 +00:00
res <- withResolver rs $ \resolver -> lookupSRV resolver $ pack $ "_mongodb._tcp." ++ hostname
case res of
Left _ -> pure []
Right srv -> pure $ map (\(_, _, por, tar) ->
let tar' = dropWhileEnd (=='.') (unpack tar)
in Host tar' (PortNumber . fromIntegral $ por)) srv