Copyright	© 2018-2020 IOHK
License	Apache-2.0
Safe Haskell	None
Language	Haskell2010

Cardano.Wallet.Network.Ports

Contents

Allocation
Status
Helpers

Description

Provides functions for checking if TCP ports can be connected to, or are available to listen on.

These can be used for: - Waiting until a server in another process has started. - Start servers for testing when there may be multiple test suites running in parallel.

Synopsis

data PortNumber
getRandomPort :: IO PortNumber
isPortOpen :: SockAddr -> IO Bool
simpleSockAddr :: ( Word8 , Word8 , Word8 , Word8 ) -> PortNumber -> SockAddr
portFromURL :: URI -> PortNumber
randomUnusedTCPPorts :: Int -> IO [ Int ]

Allocation

data PortNumber Source #

Port number. Use the Num instance (i.e. use a literal) to create a PortNumber value.

>>> 1 :: PortNumber
1
>>> read "1" :: PortNumber
1
>>> show (12345 :: PortNumber)
"12345"
>>> 50000 < (51000 :: PortNumber)
True
>>> 50000 < (52000 :: PortNumber)
True
>>> 50000 + (10000 :: PortNumber)
60000

Instances

Instances details

Bounded PortNumber
Instance details Defined in Network.Socket.Types Methods minBound :: PortNumber Source # maxBound :: PortNumber Source #
Enum PortNumber
Instance details Defined in Network.Socket.Types Methods succ :: PortNumber -> PortNumber Source # pred :: PortNumber -> PortNumber Source # toEnum :: Int -> PortNumber Source # fromEnum :: PortNumber -> Int Source # enumFrom :: PortNumber -> [ PortNumber ] Source # enumFromThen :: PortNumber -> PortNumber -> [ PortNumber ] Source # enumFromTo :: PortNumber -> PortNumber -> [ PortNumber ] Source # enumFromThenTo :: PortNumber -> PortNumber -> PortNumber -> [ PortNumber ] Source #
Eq PortNumber
Instance details Defined in Network.Socket.Types Methods (==) :: PortNumber -> PortNumber -> Bool Source # (/=) :: PortNumber -> PortNumber -> Bool Source #
Integral PortNumber
Instance details Defined in Network.Socket.Types Methods quot :: PortNumber -> PortNumber -> PortNumber Source # rem :: PortNumber -> PortNumber -> PortNumber Source # div :: PortNumber -> PortNumber -> PortNumber Source # mod :: PortNumber -> PortNumber -> PortNumber Source # quotRem :: PortNumber -> PortNumber -> ( PortNumber , PortNumber ) Source # divMod :: PortNumber -> PortNumber -> ( PortNumber , PortNumber ) Source # toInteger :: PortNumber -> Integer Source #
Num PortNumber
Instance details Defined in Network.Socket.Types Methods (+) :: PortNumber -> PortNumber -> PortNumber Source # (-) :: PortNumber -> PortNumber -> PortNumber Source # (*) :: PortNumber -> PortNumber -> PortNumber Source # negate :: PortNumber -> PortNumber Source # abs :: PortNumber -> PortNumber Source # signum :: PortNumber -> PortNumber Source # fromInteger :: Integer -> PortNumber Source #
Ord PortNumber
Instance details Defined in Network.Socket.Types Methods compare :: PortNumber -> PortNumber -> Ordering Source # (<) :: PortNumber -> PortNumber -> Bool Source # (<=) :: PortNumber -> PortNumber -> Bool Source # (>) :: PortNumber -> PortNumber -> Bool Source # (>=) :: PortNumber -> PortNumber -> Bool Source # max :: PortNumber -> PortNumber -> PortNumber Source # min :: PortNumber -> PortNumber -> PortNumber Source #
Read PortNumber
Instance details Defined in Network.Socket.Types Methods readsPrec :: Int -> ReadS PortNumber Source # readList :: ReadS [ PortNumber ] Source # readPrec :: ReadPrec PortNumber Source # readListPrec :: ReadPrec [ PortNumber ] Source #
Real PortNumber
Instance details Defined in Network.Socket.Types Methods toRational :: PortNumber -> Rational Source #
Show PortNumber
Instance details Defined in Network.Socket.Types Methods showsPrec :: Int -> PortNumber -> ShowS Source # show :: PortNumber -> String Source # showList :: [ PortNumber ] -> ShowS Source #
Storable PortNumber
Instance details Defined in Network.Socket.Types Methods sizeOf :: PortNumber -> Int Source # alignment :: PortNumber -> Int Source # peekElemOff :: Ptr PortNumber -> Int -> IO PortNumber Source # pokeElemOff :: Ptr PortNumber -> Int -> PortNumber -> IO () Source # peekByteOff :: Ptr b -> Int -> IO PortNumber Source # pokeByteOff :: Ptr b -> Int -> PortNumber -> IO () Source # peek :: Ptr PortNumber -> IO PortNumber Source # poke :: Ptr PortNumber -> PortNumber -> IO () Source #

getRandomPort :: IO PortNumber Source #

Find a TCPv4 port which is likely to be free for listening on localhost . This binds a socket, receives an OS-assigned port, then closes the socket.

Note that this is vulnerable to race conditions if another process binds the port returned by getRandomPort before this process does.

Do not use this unless you have no other option.

Status

isPortOpen :: SockAddr -> IO Bool Source #

Checks whether connect() to a given TCPv4 SockAddr succeeds or returns eCONNREFUSED .

Rethrows connection exceptions in all other cases (e.g. when the host is unroutable).

Code courtesy of nh2: https://stackoverflow.com/a/57022572

simpleSockAddr :: ( Word8 , Word8 , Word8 , Word8 ) -> PortNumber -> SockAddr Source #

Creates a SockAttr from host IP and port number.

Example: > simpleSockAddr (127,0,0,1) 8000

Helpers

portFromURL :: URI -> PortNumber Source #

Get the port from a URI, which is assumed to be a HTTP or HTTPS URL.

randomUnusedTCPPorts :: Int -> IO [ Int ] Source #

Get a list of random TCPv4 ports that currently do not have any servers listening on them. It may return less than the requested number of ports.

Note that this method of allocating ports is subject to race conditions. Production code should use better methods such as passing a listening socket to the child process.