Network.WebSockets.Connection

This module exposes connection internals and should only be used if you really know what you are doing.

Documentation

data PendingConnection

A new client connected to the server. We haven't accepted the connection yet, though.

Constructors

PendingConnection

Fields

• pendingOptions :: !ConnectionOptions

  Options, passed as-is to the Connection

• pendingRequest :: !RequestHead

  Useful for e.g. inspecting the request path.

• pendingOnAccept :: !(Connection -> IO ())

  One-shot callback fired when a connection is accepted, i.e., *after* the accepting response is sent to the client.

• pendingStream :: !Stream

  Input/output stream

acceptRequest :: PendingConnection -> IO Connection

Accept a pending connection, turning it into a Connection.

data AcceptRequest

This datatype allows you to set options for acceptRequestWith. It is strongly recommended to use defaultAcceptRequest and then modify the various fields, that way new fields introduced in the library do not break your code.

Constructors

AcceptRequest

Fields

• acceptSubprotocol :: !(Maybe ByteString)

  The subprotocol to speak with the client. If pendingSubprotcols is non-empty, acceptSubprotocol must be one of the subprotocols from the list.

• acceptHeaders :: !Headers

  Extra headers to send with the response.

defaultAcceptRequest :: AcceptRequest

acceptRequestWith :: PendingConnection -> AcceptRequest -> IO Connection

This function is like acceptRequest but allows you to set custom options using the AcceptRequest datatype.

rejectRequest

Arguments

:: PendingConnection

Connection to reject

-> ByteString

Rejection response body

-> IO ()

data RejectRequest

Parameters that allow you to tweak how a request is rejected. Please use defaultRejectRequest and modify fields using record syntax so your code will not break when new fields are added.

Constructors

RejectRequest

Fields

• rejectCode :: !Int

  The status code, 400 by default.

• rejectMessage :: !ByteString

  The message, "Bad Request" by default

• rejectHeaders :: Headers

  Extra headers to be sent with the response.

• rejectBody :: !ByteString

  Reponse body of the rejection.

defaultRejectRequest :: RejectRequest

rejectRequestWith

Arguments

:: PendingConnection

Connection to reject

-> RejectRequest

Params on how to reject the request

-> IO ()

data Connection

Constructors

Connection

Fields

• connectionOptions :: !ConnectionOptions
• connectionType :: !ConnectionType
• connectionProtocol :: !Protocol
• connectionParse :: !(IO (Maybe Message))
• connectionWrite :: !([Message] -> IO ())
• connectionSentClose :: !(IORef Bool)

  According to the RFC, both the client and the server MUST send a close control message to each other. Either party can initiate the first close message but then the other party must respond. Finally, the server is in charge of closing the TCP connection. This IORef tracks if we have sent a close message and are waiting for the peer to respond.

data ConnectionOptions

Set options for a Connection. Please do not use this constructor directly, but rather use defaultConnectionOptions and then set the fields you want, e.g.:

myOptions = defaultConnectionOptions {connectionStrictUnicode = True}

This way your code does not break if the library introduces new fields.

Constructors

ConnectionOptions

Fields

• connectionOnPong :: !(IO ())

  Whenever a pong is received, this IO action is executed. It can be used to tickle connections or fire missiles.

• connectionCompressionOptions :: !CompressionOptions

  Enable PermessageDeflate.

• connectionStrictUnicode :: !Bool

  Enable strict unicode on the connection. This means that if a client (or server) sends invalid UTF-8, we will throw a UnicodeException rather than replacing it by the unicode replacement character U+FFFD.

• connectionFramePayloadSizeLimit :: !SizeLimit

  The maximum size for incoming frame payload size in bytes. If a frame exceeds this limit, a ParseException is thrown.

• connectionMessageDataSizeLimit :: !SizeLimit

  connectionFrameSizeLimit is often not enough since a malicious client can send many small frames to create a huge message. This limit allows you to protect from that. If a message exceeds this limit, a ParseException is thrown.

  Note that, if compression is enabled, we check the size of the compressed messages, as well as the size of the uncompressed messages as we are deflating them to ensure we don't use too much memory in any case.

defaultConnectionOptions :: ConnectionOptions

The default connection options:

• Nothing happens when a pong is received.
• Compression is disabled.
• Lenient unicode decoding.

receive :: Connection -> IO Message

receiveDataMessage :: Connection -> IO DataMessage

Receive an application message. Automatically respond to control messages.

When the peer sends a close control message, an exception of type CloseRequest is thrown. The peer can send a close control message either to initiate a close or in response to a close message we have sent to the peer. In either case the CloseRequest exception will be thrown. The RFC specifies that the server is responsible for closing the TCP connection, which should happen after receiving the CloseRequest exception from this function.

This will throw ConnectionClosed if the TCP connection dies unexpectedly.

receiveData :: WebSocketsData a => Connection -> IO a

Receive a message, converting it to whatever format is needed.

send :: Connection -> Message -> IO ()

sendDataMessage :: Connection -> DataMessage -> IO ()

Send a Message. This allows you send both human-readable text and binary data. This is a slightly more low-level interface than sendTextData or sendBinaryData.

sendDataMessages :: Connection -> [DataMessage] -> IO ()

Send a collection of Messages. This is more efficient than calling sendDataMessage many times.

sendTextData :: WebSocketsData a => Connection -> a -> IO ()

Send a textual message. The message will be encoded as UTF-8. This should be the default choice for human-readable text-based protocols such as JSON.

sendTextDatas :: WebSocketsData a => Connection -> [a] -> IO ()

Send a number of textual messages. This is more efficient than calling sendTextData many times.

sendBinaryData :: WebSocketsData a => Connection -> a -> IO ()

Send a binary message. This is useful for sending binary blobs, e.g. images, data encoded with MessagePack, images...

sendBinaryDatas :: WebSocketsData a => Connection -> [a] -> IO ()

Send a number of binary messages. This is more efficient than calling sendBinaryData many times.

sendClose :: WebSocketsData a => Connection -> a -> IO ()

Send a friendly close message. Note that after sending this message, you should still continue calling receiveDataMessage to process any in-flight messages. The peer will eventually respond with a close control message of its own which will cause receiveDataMessage to throw the CloseRequest exception. This exception is when you can finally consider the connection closed.

sendCloseCode :: WebSocketsData a => Connection -> Word16 -> a -> IO ()

Send a friendly close message and close code. Similar to sendClose, you should continue calling receiveDataMessage until you receive a CloseRequest exception.

See http://tools.ietf.org/html/rfc6455#section-7.4 for a list of close codes.

sendPing :: WebSocketsData a => Connection -> a -> IO ()

Send a ping

forkPingThread :: Connection -> Int -> IO ()

Forks a ping thread, sending a ping message every n seconds over the connection. The thread dies silently if the connection crashes or is closed.

This is useful to keep idle connections open through proxies and whatnot. Many (but not all) proxies have a 60 second default timeout, so based on that sending a ping every 30 seconds is a good idea.

data CompressionOptions

Constructors

NoCompression

PermessageDeflateCompression PermessageDeflate

Instances

Eq CompressionOptions

Defined in Network.WebSockets.Connection.Options

Methods

(==) :: CompressionOptions -> CompressionOptions -> Bool

(/=) :: CompressionOptions -> CompressionOptions -> Bool

Show CompressionOptions

Defined in Network.WebSockets.Connection.Options

Methods

showsPrec :: Int -> CompressionOptions -> ShowS

show :: CompressionOptions -> String

showList :: [CompressionOptions] -> ShowS

data PermessageDeflate

Four extension parameters are defined for "permessage-deflate" to help endpoints manage per-connection resource usage.

• "server_no_context_takeover"
• "client_no_context_takeover"
• "server_max_window_bits"
• "client_max_window_bits"

Constructors

PermessageDeflate

Fields

• serverNoContextTakeover :: Bool
• clientNoContextTakeover :: Bool
• serverMaxWindowBits :: Int
• clientMaxWindowBits :: Int
• pdCompressionLevel :: Int

Instances

Eq PermessageDeflate

Defined in Network.WebSockets.Connection.Options

Methods

(==) :: PermessageDeflate -> PermessageDeflate -> Bool

(/=) :: PermessageDeflate -> PermessageDeflate -> Bool

Show PermessageDeflate

Defined in Network.WebSockets.Connection.Options

Methods

showsPrec :: Int -> PermessageDeflate -> ShowS

show :: PermessageDeflate -> String

showList :: [PermessageDeflate] -> ShowS

defaultPermessageDeflate :: PermessageDeflate

data SizeLimit

A size limit, in bytes. The Monoid instance takes the minimum limit.

Constructors

NoSizeLimit

SizeLimit !Int64

Instances

Eq SizeLimit

Defined in Network.WebSockets.Connection.Options

Methods

(==) :: SizeLimit -> SizeLimit -> Bool

(/=) :: SizeLimit -> SizeLimit -> Bool

Show SizeLimit

Defined in Network.WebSockets.Connection.Options

Methods

showsPrec :: Int -> SizeLimit -> ShowS

show :: SizeLimit -> String

showList :: [SizeLimit] -> ShowS

Semigroup SizeLimit

Defined in Network.WebSockets.Connection.Options

Methods

(<>) :: SizeLimit -> SizeLimit -> SizeLimit

sconcat :: NonEmpty SizeLimit -> SizeLimit

stimes :: Integral b => b -> SizeLimit -> SizeLimit

Monoid SizeLimit

Defined in Network.WebSockets.Connection.Options

Methods

mempty :: SizeLimit

mappend :: SizeLimit -> SizeLimit -> SizeLimit

mconcat :: [SizeLimit] -> SizeLimit