Safe Haskell	Safe-Inferred
Language	Haskell2010

API

Description

Capability record for the NATS client surface.

Synopsis

data Client = Client {
- publish :: Subject -> [PublishOption] -> IO ()
- subscribe :: Subject -> [SubscribeOption] -> (Maybe MsgView -> IO ()) -> IO SID
- request :: Subject -> [SubscribeOption] -> (Maybe MsgView -> IO ()) -> IO SID
- unsubscribe :: SID -> IO ()
- newInbox :: IO Subject
- ping :: IO () -> IO ()
- flush :: IO ()
- reset :: IO ()
- close :: IO ()
}
data MsgView = MsgView {
- subject :: ByteString
- sid :: ByteString
- replyTo :: Maybe ByteString
- payload :: Maybe ByteString
- headers :: Maybe [(ByteString, ByteString)]
}
type PublishOption = CallOption PublishConfig
type SubscribeOption = CallOption SubscribeConfig
withSubscriptionExpiry :: NominalDiffTime -> SubscribeOption
withQueueGroup :: Subject -> SubscribeOption
withPayload :: Payload -> PublishOption
withReplyCallback :: (Maybe MsgView -> IO ()) -> PublishOption
withReplyTo :: Subject -> PublishOption
withHeaders :: Headers -> PublishOption

Documentation

data Client Source #

Client capabilities for publishing, subscribing, and lifecycle control.

Constructors

Client

Fields

publish :: Subject -> [PublishOption] -> IO ()
Publish a message, optionally overriding publish options.
subscribe :: Subject -> [SubscribeOption] -> (Maybe MsgView -> IO ()) -> IO SID
Subscribe to a subject and handle delivered messages.
request :: Subject -> [SubscribeOption] -> (Maybe MsgView -> IO ()) -> IO SID
Subscribe with request semantics and auto-unsubscribe after a reply.
unsubscribe :: SID -> IO ()
Unsubscribe from a subscription by SID.
newInbox :: IO Subject
Create a unique inbox subject for replies.
ping :: IO () -> IO ()
Send a ping and run the callback when a pong arrives.
flush :: IO ()
Flush buffered writes to the server.
reset :: IO ()
Reset the client connection state.
close :: IO ()
Close the client connection and release resources.

data MsgView Source #

MsgView represents a MSG in the NATS protocol.

Constructors

MsgView
Fields subject :: ByteString The subject of the message. sid :: ByteString The SID (subscription ID) of the message. replyTo :: Maybe ByteString The replyTo subject, if any. payload :: Maybe ByteString The payload of the message, if any. headers :: Maybe [(ByteString, ByteString)] Headers associated with the message, if any.

Instances

Instances details

Show MsgView Source #
Instance details Defined in API Methods showsPrec :: Int -> MsgView -> ShowS # show :: MsgView -> String # showList :: [MsgView] -> ShowS #
Eq MsgView Source #
Instance details Defined in API Methods (==) :: MsgView -> MsgView -> Bool # (/=) :: MsgView -> MsgView -> Bool #

type PublishOption = CallOption PublishConfig Source #

type SubscribeOption = CallOption SubscribeConfig Source #

withSubscriptionExpiry :: NominalDiffTime -> SubscribeOption Source #

withSubscriptionExpiry sets the reply subscription expiry in seconds. Default: no expiry (reply subscriptions stay open until unsubscribe).

Examples:

{-# LANGUAGE OverloadedStrings #-}

subscribe client "events.created" [withSubscriptionExpiry 2] print

withQueueGroup :: Subject -> SubscribeOption Source #

withQueueGroup sets the queue group for a subscription. Default: no queue group.

withPayload :: Payload -> PublishOption Source #

withPayload is used to set the payload for a publish operation. Default: no payload.

Examples:

{-# LANGUAGE OverloadedStrings #-}

publish client "updates" [withPayload "hello"]

withReplyCallback :: (Maybe MsgView -> IO ()) -> PublishOption Source #

withReplyCallback is used to set a callback for a reply to a publish operation. Default: no reply subscription; publishes are fire-and-forget.

Examples:

{-# LANGUAGE OverloadedStrings #-}

publish client "service.echo" [withReplyCallback print]

withReplyTo :: Subject -> PublishOption Source #

withReplyTo sets an explicit reply subject for a publish operation. Default: no reply subject unless a reply callback is configured.

This option only controls the outgoing reply subject. It does not create a subscription; callers that expect multiple replies should subscribe to the reply subject themselves.

withHeaders :: Headers -> PublishOption Source #

withHeaders is used to set headers for a publish operation. Default: no headers.

Examples:

{-# LANGUAGE OverloadedStrings #-}

publish client "updates" [withHeaders [("source", "test")]]