hivemq/hivemq-mqtt-client v1.2.0

1.2.0

on GitHub

🌟 Features

• Manual message acknowledgement #304 #403
  Use case: Ensure at least once delivery from the broker even if client applications crash

  • Selectively enable manual acknowledgement for specific streams
  • Acknowledge messages that are emitted to multiple streams independently per stream
    (the client aggregates the acknowledgments before sending MQTT acknowledgements)
  • Order of manual acknowledgment does not matter
    (the client automatically ensures the order of MQTT acknowledgments for 100% compatibility with the MQTT specification)

• New Reactor API #255 #388 #397
  Use case: Easier integration into reactor applications

• Decoupled subscription/publishing lifecycles from connection/session lifecycles

  • Subscribe and unsubscribe operations can now be called irrespective of the current connection status (similar to the publishes operation) #398
    Use case: Set up subscriptions before connecting the client

  • Restore subscriptions automatically if the session expires and the client reconnects (enabled by default, configurable) #297 #398
    Use case: Easier to build continuously-connected applications that need to maintain their subscriptions as long as the application is running (even in the edge case that the session expires)

  • Republish pending and queued messages even if the session expires and the client reconnects (disabled by default, configurable) #288 #398
    Use case: Easier to build continuously-connected applications that want to ensure at-least-once delivery to the broker (even in the edge case that the session expires)

• New transport features:

  • Proxy support: SOCKS4, SOCKS5, HTTP CONNECT #81 #281 #364 #401
    Use case: Tunnel the MQTT connection through a proxy

  • Improved TLS support: #201 #401

    • TLS Session Resumption
      Use case: Consume less bandwidth and computing resources when reconnecting and resuming a TLS session
    • Hostname verification: Default is the same as HTTPS hostname verification, but can be customized
      Usecase: Verify that you are communicating with the right broker

  • Specify a WebSocket query string #335 #336
    Usecase: Communicate with WebSocket endpoints that require a query string

  • Specify the local bind address and/or port #308 #365
    Use case: Support multiple network interfaces

  • Configurable timeouts: #401

    • Socket connect timeout
    • MQTT connect timeout
    • WebSocket handshake timeout
    • Proxy handshake timeout

• New bulk builder methods for consuming arrays, collections, or streams: #170 #290 #387

  • User properties builder addAll
  • Subscribe builder addSubscriptions
  • Unsubscribe builder addTopicFilters

✨ Improvements

• Added CheckReturnValue annotation that enables IDE assistance to flag unused return values #385
• Javadoc and code style improvements #404 #406 #407

🗒️ Misc

• Modularization of artifacts #364
  Reasoning: Keep required dependencies to a minimum, future releases might add more modules for diverse integrations
  • hivemq-mqtt-client: Base dependency
  • hivemq-mqtt-client-websocket: Adds dependencies for the WebSocket transport
  • hivemq-mqtt-client-proxy: Adds dependencies for the proxy transport
  • hivemq-mqtt-client-epoll: Adds dependencies for the native epoll socket implementation
  • hivemq-mqtt-client-reactor: Reactor API for the HiveMQ MQTT Client

⚠️ Behavioral changes

• By default, subscriptions are now automatically restored when the session expires and the client reconnects.
  If desired, the default behavior can be disabled with MqttClientReconnector.resubscribeIfSessionExpired(false)

• When TLS is used, HTTPS hostname verification is now performed by default, but can be customized with MqttClientSslConfigBuilder.hostnameVerifier

• The hivemq-mqtt-client artifact in version 1.1.4 and below is now modularized into the artifacts hivemq-mqtt-client, hivemq-mqtt-client-websocket, and hivemq-mqtt-client-epoll
  If you use the WebSocket transport or the native epoll socket implementation, please specify the additional dependencies

❤️ Thanks to all contributors

• @alsanrum
• @MicWalter
• @SgtSilvio
• Also thanks to all code reviewers and all who created valuable issues

Related blog post: https://www.hivemq.com/blog/hivemq-mqtt-client-1-2-0-released/