Network.Nats.Types

Base types for the library's API. JSON support is implemented with Data.Aeson.

Documentation

type Topic = ByteString

The type of a topic where to publish, or to subscribe on. Type alias for ByteString.

type Payload = ByteString

The type of a message payload. Type alias for ByteString.

type Sid = Int64

The numeric id for a subscription. An id shall be unique within a NATS client. The value of the id will be generated automatically by the API. Type alias for Int64.

type QueueGroup = ByteString

A Topic subscriber can be part of a queue group, an entity for load balancing in NATS. Type alias for ByteString.

data NatsException

Exceptions generated from within this library.

Constructors

HandshakeException

An exception caused by errors during the NATS connection handshake. Will not popup on user level, only handled internally.

ConnectionGiveUpException

An exception thrown when all the configured connection attempts are consumed and the connection manager has been given up.

AuthorizationException

The NATS server currently connected to has said that there are authorization violations. Don't try to survive, just tell the user that there are such errors.

URIError !String

An exception caused by invalid URI strings given to the withNats function.

Instances

Show NatsException

Methods

showsPrec :: Int -> NatsException -> ShowS

show :: NatsException -> String

showList :: [NatsException] -> ShowS

Exception NatsException

Methods

toException :: NatsException -> SomeException

fromException :: SomeException -> Maybe NatsException

displayException :: NatsException -> String

newtype MsgQueue

A message queue, a queue of Msgs handled by a TQueue.

Constructors

MsgQueue (TQueue Msg)

data Msg

A NATS message as received by the user. The message itself is opaque to the user, but the fields can be read by the API functions topic, replyTo, sid, payload, jsonPayload and jsonPayload'

Constructors

Msg !Topic !(Maybe Topic) !Sid !Payload

Instances

Eq Msg

Methods

(==) :: Msg -> Msg -> Bool

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

Show Msg

Methods

showsPrec :: Int -> Msg -> ShowS

show :: Msg -> String

showList :: [Msg] -> ShowS

topic :: Msg -> Topic

Read the complete topic on which a message was received.

replyTo :: Msg -> Maybe Topic

Read the reply-to topic from a received message.

sid :: Msg -> Sid

Read the subscription id for the subscription on which this message was received.

payload :: Msg -> Payload

Read the raw payload from a received message.

jsonPayload :: FromJSON a => Msg -> Maybe a

Decode a message's payload as JSON. Is using decode for the decoding.

jsonPayload' :: FromJSON a => Msg -> Maybe a

Decode a message's payload as JSON. Is using decode' for the decoding.