Copyright	© 2020 Herbert Valerio Riedel
License	GPL-2.0-or-later
Safe Haskell	None
Language	Haskell2010

Network.Http.Client.WebSocket

Contents

WebSocket Frames
- WebSocket Frame Header
- Mid-level I/O primitives
  - Sending WebSocket frames
  - Receiving WebSocket frames
WebSocket handshake
- HTTP/1.1 WebSocket connection upgrade
- Low-level primitives for WebSocket handshake
Exception

Description

Basic WebSocket RFC 6455 support.

Since: 0.1.4.0

Synopsis

data WSFrameHdr = WSFrameHdr {
- ws'FIN :: !Bool
- ws'RSV1 :: !Bool
- ws'RSV2 :: !Bool
- ws'RSV3 :: !Bool
- ws'opcode :: !WSOpcode
- ws'length :: !Word64
- ws'mask :: !(Maybe Word32)
}
wsFrameHdrSize :: WSFrameHdr -> Int
wsFrameHdrToBuilder :: WSFrameHdr -> Builder
data WSOpcode
- = WSOpcode'Continuation
- | WSOpcode'Text
- | WSOpcode'Binary
- | WSOpcode'Close
- | WSOpcode'Ping
- | WSOpcode'Pong
- | WSOpcode'Reserved !WSOpcodeReserved
data WSOpcodeReserved
wsIsDataFrame :: WSOpcode -> Bool
writeWSFrame :: Connection -> WSOpcode -> Maybe Word32 -> ByteString -> IO ()
sendWSFragData :: Connection -> WSFrameHdr -> (OutputStream ByteString -> IO a) -> IO a
readWSFrame :: Int -> Connection -> IO (Maybe (WSFrameHdr, ByteString))
receiveWSFrame :: Connection -> (WSFrameHdr -> InputStream ByteString -> IO a) -> IO (Maybe a)
wsUpgradeConnection :: Connection -> ByteString -> RequestBuilder α -> SecWebSocketKey -> (Response -> InputStream ByteString -> IO b) -> (Response -> Connection -> IO b) -> IO b
data SecWebSocketKey
wsKeyToAcceptB64 :: SecWebSocketKey -> ByteString
secWebSocketKeyFromB64 :: ByteString -> Maybe SecWebSocketKey
secWebSocketKeyToB64 :: SecWebSocketKey -> ByteString
secWebSocketKeyFromWords :: Word64 -> Word64 -> SecWebSocketKey
data WsException = WsException String

WebSocket Frames

WebSocket Frame Header

data WSFrameHdr Source #

WebSocket Frame as per RFC 6455 section 5.2

 0                   1                   2                   3
 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-------+-+-------------+-------------------------------+
|F|R|R|R| opcode|M| Payload len |    Extended payload length    |
|I|S|S|S|  (4)  |A|     (7)     |             (16/64)           |
|N|V|V|V|       |S|             |   (if payload len==126/127)   |
| |1|2|3|       |K|             |                               |
+-+-+-+-+-------+-+-------------+ - - - - - - - - - - - - - - - +
|     Extended payload length continued, if payload len == 127  |
+ - - - - - - - - - - - - - - - +-------------------------------+
|                               |Masking-key, if MASK set to 1  |
+-------------------------------+-------------------------------+
| Masking-key (continued)       |          Payload Data         |
+-------------------------------- - - - - - - - - - - - - - - - +
:                     Payload Data continued ...                :
+ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - +
|                     Payload Data continued ...                |
+---------------------------------------------------------------+

Since: 0.1.4.0

Constructors

WSFrameHdr

Fields

ws'FIN :: !Bool
MUST be set for control-frames (control-frames MUST NOT be fragmented).
ws'RSV1 :: !Bool
ws'RSV2 :: !Bool
ws'RSV3 :: !Bool
ws'opcode :: !WSOpcode
ws'length :: !Word64
MUST be smaller than 2^63 for data-frames; MUST be smaller than 126 for control-frames.
ws'mask :: !(Maybe Word32)
Whether the frame is masked and which masking key is used; Nothing denotes unmasked frames.
A client MUST mask all frames that it sends to the server; A server MUST NOT mask any frames that it sends to the client.

Instances

Instances details

Show WSFrameHdr Source #
Instance details Defined in Network.Http.Client.WebSocket Methods showsPrec :: Int -> WSFrameHdr -> ShowS # show :: WSFrameHdr -> String # showList :: [WSFrameHdr] -> ShowS #
Binary WSFrameHdr Source #
Instance details Defined in Network.Http.Client.WebSocket Methods put :: WSFrameHdr -> Put # get :: Get WSFrameHdr # putList :: [WSFrameHdr] -> Put #

wsFrameHdrSize :: WSFrameHdr -> Int Source #

Size of serialized WebSocket frame header (i.e. without payload data) in octets.

Since: 0.1.4.0

wsFrameHdrToBuilder :: WSFrameHdr -> Builder Source #

Serialize WSFrameHdr to Builder

Since: 0.1.4.0

data WSOpcode Source #

WebSocket frame opcode.

Instances

Instances details

Show WSOpcode Source #
Instance details Defined in Network.Http.Client.WebSocket Methods showsPrec :: Int -> WSOpcode -> ShowS # show :: WSOpcode -> String # showList :: [WSOpcode] -> ShowS #
Eq WSOpcode Source #
Instance details Defined in Network.Http.Client.WebSocket Methods (==) :: WSOpcode -> WSOpcode -> Bool # (/=) :: WSOpcode -> WSOpcode -> Bool #

data WSOpcodeReserved Source #

WebSocket frame opcodes reserved for future use by RFC 6455

Since: 0.1.4.0

Constructors

WSOpcode'Reserved3
WSOpcode'Reserved4
WSOpcode'Reserved5
WSOpcode'Reserved6
WSOpcode'Reserved7
WSOpcode'Reserved11
WSOpcode'Reserved12
WSOpcode'Reserved13
WSOpcode'Reserved14
WSOpcode'Reserved15

Instances

Instances details

Show WSOpcodeReserved Source #
Instance details Defined in Network.Http.Client.WebSocket Methods showsPrec :: Int -> WSOpcodeReserved -> ShowS # show :: WSOpcodeReserved -> String # showList :: [WSOpcodeReserved] -> ShowS #
Eq WSOpcodeReserved Source #
Instance details Defined in Network.Http.Client.WebSocket Methods (==) :: WSOpcodeReserved -> WSOpcodeReserved -> Bool # (/=) :: WSOpcodeReserved -> WSOpcodeReserved -> Bool #

wsIsDataFrame :: WSOpcode -> Bool Source #

Whether WSOpcode denotes a data-frame.

There are two kinds of WebSocket frames, data-frames and control-frames. Consequently, this predicate is False for control-frames.

Since: 0.1.4.0

Mid-level I/O primitives

Sending WebSocket frames

writeWSFrame :: Connection -> WSOpcode -> Maybe Word32 -> ByteString -> IO () Source #

Convenience function for writing simple non-fragmented frames to an established WebSocket connection.

Control-frames MUST have a payload smaller than 126 bytes.

Since: 0.1.4.0

sendWSFragData :: Connection -> WSFrameHdr -> (OutputStream ByteString -> IO a) -> IO a Source #

Send WebSocket message as fragmented data-frames.

This function can be used if the size of the data payload to be sent is not known in advance.

This operation does not flush automatically after every chunk; write an empty chunk to the OutputStream to trigger flushing pending data onto the WebSocket connection.

The ws'length and ws'FIN fields are ignored and computed from the chunks to be sent.

Pre-conditions:

This function does not support sending control-frames as those MUST NOT be fragmented.
ws'opcode MUST NOT be WSOpcode'Continuation

Since: 0.1.4.0

Receiving WebSocket frames

readWSFrame :: Int -> Connection -> IO (Maybe (WSFrameHdr, ByteString)) Source #

Convenience function for reading a single (possibly fragmented) frame from an established WebSocket connection.

The first argument is the maximum expected frame size to receive; if a larger frame is encountered an exception is raised.

This operation does not perform any defragmentation nor automatically deal with control-frames (those will be returned to the caller as-is).

Returns Nothing if the InputStream is terminated before reading the first octet.

Since: 0.1.4.0

receiveWSFrame :: Connection -> (WSFrameHdr -> InputStream ByteString -> IO a) -> IO (Maybe a) Source #

Receive a single WebSocket frame as InputStream.

This operation does not perform any defragmentation nor automatically deal with control-frames (those will be returned to the caller as-is).

See also readWSFrame for a simple non-streaming version.

Since: 0.1.4.0

WebSocket handshake

HTTP/1.1 WebSocket connection upgrade

wsUpgradeConnection Source #

Arguments

:: Connection	Connection in HTTP/1.1 protocol state (i.e. not yet upgraded)
-> ByteString	resource name (i.e. the argument to the `GET` verb)
-> RequestBuilder α	Additional Handshake request builder operations (i.e. to add additional HTTP headers to Handshake HTTP request)
-> SecWebSocketKey	The `sec-websocket-key` value to use
-> (Response -> InputStream ByteString -> IO b)	failure continuation if handshake fails with a non-101 response code
-> (Response -> Connection -> IO b)	success continuation; the `Connection` has been succesfully upgraded to WebSocket mode and only WebSocket operations shall be performed over this `Connection`.
-> IO b

Perform an opening WebSocket handshake as per RFC 6455 section 4

This operation sets the host, upgrade, connection, sec-websocket-version, sec-websocket-key HTTP headers; if you need to customize the handshake request further use the BuildRequest-modifier argument to inject more headers into the request.

Since: 0.1.4.0

Low-level primitives for WebSocket handshake

data SecWebSocketKey Source #

Sec-WebSocket-Key header value according to RFC 6455

Since: 0.1.4.0

Instances

Instances details

Show SecWebSocketKey Source #
Instance details Defined in Network.Http.Client.WebSocket Methods showsPrec :: Int -> SecWebSocketKey -> ShowS # show :: SecWebSocketKey -> String # showList :: [SecWebSocketKey] -> ShowS #
Eq SecWebSocketKey Source #
Instance details Defined in Network.Http.Client.WebSocket Methods (==) :: SecWebSocketKey -> SecWebSocketKey -> Bool # (/=) :: SecWebSocketKey -> SecWebSocketKey -> Bool #
Ord SecWebSocketKey Source #
Instance details Defined in Network.Http.Client.WebSocket Methods compare :: SecWebSocketKey -> SecWebSocketKey -> Ordering # (<) :: SecWebSocketKey -> SecWebSocketKey -> Bool # (<=) :: SecWebSocketKey -> SecWebSocketKey -> Bool # (>) :: SecWebSocketKey -> SecWebSocketKey -> Bool # (>=) :: SecWebSocketKey -> SecWebSocketKey -> Bool # max :: SecWebSocketKey -> SecWebSocketKey -> SecWebSocketKey # min :: SecWebSocketKey -> SecWebSocketKey -> SecWebSocketKey #

wsKeyToAcceptB64 :: SecWebSocketKey -> ByteString Source #

Compute Sec-WebSocket-Accept header value from Sec-WebSocket-Key header value according to RFC 6455

>>> wsKeyToAcceptB64 <$> secWebSocketKeyFromB64 "dGhlIHNhbXBsZSBub25jZQ=="
Just "s3pPLMBiTxaQ9kYGzzhZRbK+xOo="

Since: 0.1.4.0

secWebSocketKeyFromB64 :: ByteString -> Maybe SecWebSocketKey Source #

Construct SecWebSocketKey from its HTTP header base64 representation.

The input must be a valid Sec-WebSocket-Key value, i.e. a base64 encoded 16-octet value (i.e. 24 base64 characters) with optional surrounding whitespace (TAB or SPC) characters or this function will return Nothing.

Since: 0.1.4.0

secWebSocketKeyToB64 :: SecWebSocketKey -> ByteString Source #

Emit SecWebSocketKey as base64-encoded value suitable for use in the Sec-WebSocket-Accept HTTP header.

Since: 0.1.4.0

secWebSocketKeyFromWords :: Word64 -> Word64 -> SecWebSocketKey Source #

Construct SecWebSocketKey from two Word64 values.

Since: 0.1.4.0

Exception

data WsException Source #

Exception type thrown by WebSocket routines.

These exceptions mostly denote WebSocket protocol violations from either side, client and server.

Since: 0.1.4.0

Constructors

WsException String

Instances

Instances details

Exception WsException Source #
Instance details Defined in Network.Http.Client.WebSocket Methods toException :: WsException -> SomeException # fromException :: SomeException -> Maybe WsException # displayException :: WsException -> String #
Show WsException Source #
Instance details Defined in Network.Http.Client.WebSocket Methods showsPrec :: Int -> WsException -> ShowS # show :: WsException -> String # showList :: [WsException] -> ShowS #

WSOpcode'Continuation	data fragmented data-frame
WSOpcode'Text	data payload must utf-8 encoded
WSOpcode'Binary	data binary data payload
WSOpcode'Close	control connection close frame (optional payload with reason-code)
WSOpcode'Ping	control PING frame
WSOpcode'Pong	control PONG frame
WSOpcode'Reserved !WSOpcodeReserved	reserved frame kind not defined by RFC 6455