License	BSD-style
Maintainer	Vincent Hanquez <vincent@snarc.org>
Stability	experimental
Portability	portable
Safe Haskell	None
Language	Haskell98

Network.Connection

Contents

Type for a connection
Exceptions
Library initialization
Connection operation
Sending and receiving data
TLS related operation

Description

Simple connection abstraction

Synopsis

Type for a connection

data Connection

This opaque type represent a connection to a destination.

connectionID :: Connection -> ConnectionID

return a simple tuple of the port and hostname that we're connected to.

data ConnectionParams

Connection Parameters to establish a Connection.

The strict minimum is an hostname and the port.

If you need to establish a TLS connection, you should make sure connectionUseSecure is correctly set.

If you need to connect through a SOCKS, you should make sure connectionUseSocks is correctly set.

Constructors

ConnectionParams
Fields connectionHostname :: HostName host name to connect to. connectionPort :: PortNumber port number to connect to. connectionUseSecure :: Maybe TLSSettings optional TLS parameters. connectionUseSocks :: Maybe ProxySettings optional Proxy/Socks configuration.

data TLSSettings

TLS Settings that can be either expressed as simple settings, or as full blown TLS.Params settings.

Unless you need access to parameters that are not accessible through the simple settings, you should use TLSSettingsSimple.

Constructors

TLSSettingsSimple	Simple TLS settings. recommended to use.
Fields settingDisableCertificateValidation :: Bool Disable certificate verification completely, this make TLS/SSL vulnerable to a MITM attack. not recommended to use, but for testing. settingDisableSession :: Bool Disable session management. TLS/SSL connections will always re-established their context. Not Implemented Yet. settingUseServerName :: Bool Use server name extension. Not Implemented Yet.
TLSSettings ClientParams	full blown TLS Settings directly using TLS.Params. for power users.

Instances

Show TLSSettings
Default TLSSettings

data ProxySettings

Proxy settings for the connection.

OtherProxy handles specific application-level proxies like HTTP proxies.

The simple SOCKS settings is just the hostname and portnumber of the SOCKS proxy server.

That's for now the only settings in the SOCKS package, socks password, or any sort of other authentications is not yet implemented.

Constructors

SockSettingsSimple HostName PortNumber
SockSettingsEnvironment (Maybe String)
OtherProxy HostName PortNumber

type SockSettings = ProxySettings

Exceptions

data LineTooLong

This is the exception raised if we reached the user specified limit for the line in ConnectionGetLine.

Constructors

LineTooLong

Instances

Show LineTooLong
Exception LineTooLong

Library initialization

initConnectionContext :: IO ConnectionContext

Initialize the library with shared parameters between connection.

data ConnectionContext

Shared values (certificate store, sessions, ..) between connections

At the moment, this is only strictly needed to shared sessions and certificates when using a TLS enabled connection.

Connection operation

connectFromHandle :: ConnectionContext -> Handle -> ConnectionParams -> IO Connection

Use an already established handle to create a connection object.

if the TLS Settings is set, it will do the handshake with the server. The SOCKS settings have no impact here, as the handle is already established

connectTo

Arguments

:: ConnectionContext	The global context of this connection.
-> ConnectionParams	The parameters for this connection (where to connect, and such).
-> IO Connection	The new established connection on success.

connect to a destination using the parameter

connectionClose :: Connection -> IO ()

Close a connection.

Sending and receiving data

connectionGet :: Connection -> Int -> IO ByteString

Get some bytes from a connection.

The size argument is just the maximum that could be returned to the user. The call will return as soon as there's data, even if there's less than requested. Hence, it behaves like hGetSome.

On end of input, connectionGet returns 0, but subsequent calls will throw an isEOFError exception.

connectionGetChunk :: Connection -> IO ByteString

Get the next block of data from the connection.

connectionGetChunk' :: Connection -> (ByteString -> (a, ByteString)) -> IO a

Like connectionGetChunk, but return the unused portion to the buffer, where it will be the next chunk read.

connectionGetLine

Arguments

:: Int	Maximum number of bytes before raising a LineTooLong exception
-> Connection	Connection
-> IO ByteString	The received line with the LF trimmed

Get the next line, using ASCII LF as the line terminator.

This throws an isEOFError exception on end of input, and LineTooLong when the number of bytes gathered is over the limit without a line terminator.

The actual line returned can be bigger than the limit specified, provided that the last chunk returned by the underlaying backend contains a LF. In another world only when we need more input and limit is reached that the LineTooLong exception will be raised.

An end of file will be considered as a line terminator too, if line is not empty.

connectionPut :: Connection -> ByteString -> IO ()

Put a block of data in the connection.

TLS related operation

connectionSetSecure :: ConnectionContext -> Connection -> TLSSettings -> IO ()

Activate secure layer using the parameters specified.

This is typically used to negociate a TLS channel on an already establish channel, e.g. supporting a STARTTLS command. it also flush the received buffer to prevent application confusing received data before and after the setSecure call.

If the connection is already using TLS, nothing else happens.

connectionIsSecure :: Connection -> IO Bool

Returns if the connection is establish securely or not.