Network.Greskell.WebSocket.Connection

Make a Connection

connect :: Settings s -> Host -> Port -> IO (Connection s)

Make a Connection to a Gremlin Server.

If it fails to connect to the specified server, it throws an exception.

close :: Connection s -> IO ()

Close the Connection.

If there are pending requests in the Connection, close function blocks for them to complete or time out.

Calling close on a Connection already closed (or waiting to close) does nothing.

data Connection s

A WebSocket connection to a Gremlin Server.

Type s is the body of Response, as in ResponseMessage.

type Host = String

Host name or an IP address.

type Port = Int

TCP port number.

Settings for Connection

module Network.Greskell.WebSocket.Connection.Settings

Make a request

sendRequest :: Operation o => Connection s -> o -> IO (ResponseHandle s)

Make a RequestMessage from an Operation and send it.

Usually this function does not throw any exception. Exceptions about sending requests are reported when you operate on ResponseHandle.

sendRequest' :: Connection s -> RequestMessage -> IO (ResponseHandle s)

Like sendRequest, but you can pass a RequestMessage directly to this function.

data ResponseHandle s

A handle associated in a Connection for a pair of request and response. You can retrieve ResponseMessages from this object.

Type s is the body of the response.

Instances

Functor ResponseHandle

Methods

fmap :: (a -> b) -> ResponseHandle a -> ResponseHandle b

(<$) :: a -> ResponseHandle b -> ResponseHandle a

nextResponse :: ResponseHandle s -> IO (Maybe (ResponseMessage s))

Get a ResponseMessage from ResponseHandle. If you have already got all responses, it returns Nothing. This function may block for a new ResponseMessage to come.

On error, it may throw all sorts of exceptions including RequestException.

nextResponseSTM :: ResponseHandle s -> STM (Maybe (ResponseMessage s))

STM version of nextResponse.

slurpResponses :: ResponseHandle s -> IO (Vector (ResponseMessage s))

Get all remaining ResponseMessages from ResponseHandle.

Exceptions

data GeneralException

Exception general to a Connection. It's not related to specific requests.

Constructors

UnexpectedRequestId UUID

Server sends a ResponseMessage with unknown requestId, which is kept in this exception.

ResponseParseFailure String

The Connection fails to parse a data from the server. The error message is kept in this exception.

Instances

Eq GeneralException

Methods

(==) :: GeneralException -> GeneralException -> Bool

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

Show GeneralException

Methods

showsPrec :: Int -> GeneralException -> ShowS

show :: GeneralException -> String

showList :: [GeneralException] -> ShowS

Exception GeneralException

Methods

toException :: GeneralException -> SomeException

fromException :: SomeException -> Maybe GeneralException

displayException :: GeneralException -> String

data RequestException

An exception related to a specific request.

Constructors

AlreadyClosed

The connection is already closed before it sends the request.

ServerClosed

The server closed the connection before it sends response for this request.

DuplicateRequestId UUID

The requestId (kept in this object) is already pending in the connection.

ResponseTimeout

The server fails to send ResponseMessages within responseTimeout.

Instances

Eq RequestException

Methods

(==) :: RequestException -> RequestException -> Bool

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

Show RequestException

Methods

showsPrec :: Int -> RequestException -> ShowS

show :: RequestException -> String

showList :: [RequestException] -> ShowS

Exception RequestException

Methods

toException :: RequestException -> SomeException

fromException :: SomeException -> Maybe RequestException

displayException :: RequestException -> String