# centrifuge 0.10.0

Dart client to communicate with Centrifuge and Centrifugo from Flutter and VM over WebSockets





## Installing
```
export PUB_HOSTED_URL=https://pub.mirror.p-hatan.ir
flutter pub add 'centrifuge:0.10.0'
```
Published: 2023-06-29T04:49:38.725992Z
Expected archive SHA-256: a278ecc0b2e56822e5962f5f193d15684e46de597911b3cba1b45f371cd447b3

Available in cache; verification: upstream_checksum
## Direct dependencies
- fixnum: ^1.0.0
- meta: ^1.3.0
- protobuf: ^2.0.0
- web_socket_channel: ^2.3.0

## Package README (untrusted upstream documentation)
Websocket client for [Centrifugo](https://github.com/centrifugal/centrifugo) server and [Centrifuge](https://github.com/centrifugal/centrifuge) library. 

There is no v1 release of this library yet – API still evolves. At the moment patch version updates only contain backwards compatible changes, minor version updates can have backwards incompatible API changes.

Check out [client SDK API specification](https://centrifugal.dev/docs/transports/client_api) to learn how this SDK behaves. It's recommended to read that before starting to work with this SDK as the spec covers common SDK behavior - describes client and subscription state transitions, main options and methods. Also check out examples folder.

The features implemented by this SDK can be found in [SDK feature matrix](https://centrifugal.dev/docs/transports/client_sdk#sdk-feature-matrix).

Note that custom WebSocket connection Upgrade headers can only be set on platforms that support `dart:io`. So notably custom headers set in the configuration of `Client` are ignored on the web platform.

> **The latest `centrifuge-dart` is compatible with [Centrifugo](https://github.com/centrifugal/centrifugo) server v5 and v4 and [Centrifuge](https://github.com/centrifugal/centrifuge) >= 0.25.0. For Centrifugo v2, Centrifugo v3 and Centrifuge < 0.25.0 you should use `centrifuge-dart` v0.8.0.**

## Examples

* `example\flutter_app` simple chat application
* `example\chat_app` one more chat example
* `example\console` simple console application

## Usage in background

When a mobile application goes to the background there are OS-specific limitations for established persistent connections - which can be silently closed shortly. Thus in most cases you need to disconnect from a server when app moves to the background and connect again when app goes to the foreground.

## Instructions for maintainers/contributors

### How to update protobuf definitions

1) Install `protoc` compiler
2) Install `protoc_plugin` https://pub.dev/packages/protoc_plugin (`dart pub global activate protoc_plugin`)
3) cd `lib/src/proto` and run `protoc --dart_out=. -I . client.proto`
4) cd to root and run `dartfmt -w lib/ test/` (install dartfmt with `dart pub global activate dart_style`)

### How to release

1) Update changelog
2) Bump version in `pubspec.yaml`, push, create new tag
3) `dart pub publish`

## Author

German Saprykin, saprykin.h@gmail.com

## Changelog
## [0.10.0]

**Breaking change!** This release changes the semantics of working with connection tokens described in [Centrifugo v5 release post](https://centrifugal.dev/blog/2023/06/29/centrifugo-v5-released#token-behaviour-adjustments-in-sdks).

Previously, returning an empty token string from `getToken` callback resulted in client disconnection with unauthorized reason.

Now returning an empty string from `getToken` is a valid scenario which won't result into disconnect on the client side. It's still possible to disconnect client by throwing a special `UnauthorizedException` from `getToken` function.

And we are putting back `setToken` method to the SDK – so it's now possible to reset the token to be empty upon user logout.

## [0.9.4]

* Improving reconnect behaviour upon bad network conditions (like connect timeout), [#79](https://github.com/centrifugal/centrifuge-dart/pull/79)
* [#79](https://github.com/centrifugal/centrifuge-dart/pull/79) also handles ClientDisconnectedError in _onPing method, addresses [#76](https://github.com/centrifugal/centrifuge-dart/issues/76)

## [0.9.3]

* Add support for web platform – [#73](https://github.com/centrifugal/centrifuge-dart/pull/73)

## [0.9.2]

* Fix null check for close reason, fixes [#66](https://github.com/centrifugal/centrifuge-dart/issues/66)
* Close subscription streams on remove [#67](https://github.com/centrifugal/centrifuge-dart/pull/67)

## [0.9.1]

* Fix setting initial connection token
* Fix setting connection data
* Fix LateInitializationError if transport is not initialized yet
* Better string representation of `UnsubscribedEvent`

## [0.9.0]

**Breaking changes**

This release adopts a new iteration of Centrifugal protocol and a new iteration of API. Client now behaves according to the client [SDK API specification](https://centrifugal.dev/docs/transports/client_api). The work has been done according to [Centrifugo v4 roadmap](https://github.com/centrifugal/centrifugo/issues/500).

Check out [Centrifugo v4 release post](https://centrifugal.dev/blog/2022/07/19/centrifugo-v4-released) that covers the reasoning behind changes.

All the current core features of Centrifugal client protocol are now supported here.  

New release only works with Centrifugo >= v4.0.0 and [Centrifuge](https://github.com/centrifugal/centrifuge) >= 0.25.0. See [Centrifugo v4 migration guide](https://centrifugal.dev/docs/getting-started/migration_v4) for details about the changes in the ecosystem.

Note, that Centrifugo v4 supports clients working over the previous protocol iteration, so you can update Centrifugo to v4 without any changes on the client side (but you need to turn on `use_client_protocol_v1_by_default` option in the configuration of Centrifugo, see Centrifugo v4 migration guide for details).

## [0.8.0]

Version 0.8.0 is the next iteration of `centrifuge-dart` development. It pushes client closer to other clients in the ecosystem. It also **contains several backwards incompatible changes**.

* Return Futures from `Client.connect`, `Client.disconnect`, `Subscription.subscribe`, `Subscription.unsubscribe` methods - addresses [#31](https://github.com/centrifugal/centrifuge-dart/issues/31).
* On initial connect fire `DisconnectEvent` on connection error - this makes behavior of `centrifuge-dart` similar to all other our clients - addresses [#56](https://github.com/centrifugal/centrifuge-dart/issues/56).
* Add client error stream to consume `ErrorEvent` - each transport failure will emit error to this stream - addresses [#56](https://github.com/centrifugal/centrifuge-dart/issues/56).
* Refactor subscription statuses - add `subscribing` and `error` statuses. This change is mostly internal should not affect working with Subscriptions.
* Do not call `UnsubscribeEvent` if subscription is not successfully subscribed (i.e. in `subscribed` state). This makes behavior of `centrifuge-dart` similar to all other our clients.
* Update disconnect reasons due to failed connection and calling `Client.Disconnect` method - make it more similar to all other connector libraries in ecosystem.
* Add default transport timeout (10 sec) – on connect and subscribe timeouts client will auto reconnect, calls like publish, history, rpc can now throw `TimeoutException`. Also - properly pass timeout to the transport (was not before!). Again – this makes client behave similarly to all other connectors.
* Add `presence` and `presenceStats` methods for Subscription and on client top level (for server-side subscriptions).
* Support `streamPosition` in `SubscribeSuccessEvent`.
* Support `streamPosition` in `ServerSubscribeEvent`.
* Support `data` in `ServerSubscribeEvent`.
* Implement `send` method to send async messages to a server.
* Fix deletion during iteration over map when working with server-side subscriptions.
* Better event String representations.
* Improvements and fixes in examples.

## [0.7.1]

* Add support for `data` in `SubscribeSuccessEvent`. This is a custom data which can be sent by a server towards client connection in subscribe result. Note that due to the bug in Centrifugo server this feature only works in Centrifugo >= v3.0.3.

## [0.7.0]

Update to work with Centrifuge >= v0.18.0 and Centrifugo v3.

**Breaking change** in server behavior. Client History API behavior changed in Centrifuge >= v0.18.0 and Centrifugo >= v3.0.0. When using history call it won't return all publications in a stream by default. See Centrifuge [v0.18.0 release notes](https://github.com/centrifugal/centrifuge/releases/tag/v0.18.0) or [Centrifugo v3 migration guide](https://centrifugal.dev/docs/getting-started/migration_v3) for more information and workaround on server-side.

* Protocol definitions updated to the latest version 
* History method now accepts optional `limit`, `since` and `reverse` arguments and returns `HistoryResult`
* RPC call now requires method name as first argument (you can pass empty string to mimic previous behavior)
* Publish now returns `PublishResult`
* When working with Centrifugo v3 or Centrifuge >= v0.18.0 it's now possible to avoid using `?format=protobuf` in connection URL. Client will negotiate Protobuf protocol with a server using WebSocket subprotocol mechanism (in request headers).

## [0.6.0]

Null safety migration

* library dependencies updated to null safe versions
* library code updated to support null safety in places where required

See issue [#47](https://github.com/centrifugal/centrifuge-dart/issues/47) and pull request [#48](https://github.com/centrifugal/centrifuge-dart/pull/48) for details.

## [0.5.1]
* Skip handling for events from server-side subscriptions resulted in null pointer dereference 

## [0.5.0]
* Update protobuf dependency to `^1.0.1`, thanks [@Holofox](https://github.com/Holofox)

## [0.4.1]
* Implement `removeSubscription` method, thanks [@tiamo](https://github.com/tiamo)

## [0.4.0]
* **Breaking changes** `connected` property removed

## [0.3.0]
* **Breaking changes** Changed API to avoid returning futures where they do not make sense – in `connect` and `subscribe` methods.
* Client now uses Websocket Ping/Pong frames to find broken connection
* Support for private channel subscription using `onPrivateSub` configuration callback function
* Fix several null pointer dereferences in edge cases, throw `ClientDisconnectedError` when there is an attempt to send protocol request over non-connected client.
* Fix examples where subscribe could happen before stream handlers set

## [0.2.0]
* **Breaking changes** Replaced subscribe method with getSubscription in Client. 
* Added reconnection.
* Added history method to Subscription. Thanks [vanelizarov](https://github.com/vanelizarov).
* Added rpc method.

## [0.1.0]
* Added authorization with JWT
* Added subscription to private channel with JWT

## [0.0.1]

* Initial release