Paul Fake
b2c31331b6
We had been seeing an issue in which the queue could grow larger than the configured cap. I examined the code and saw that this could happen if _mqttClient.PublishAsync() throws an exception, in which case a message can be re-enqueued without honoring the cap. Furthermore, I saw that it was possible for the DropOldestQueuedMessage strategy to drop messages that were not actually the oldest ones, because when re-enqueueing the messages in the queue are no longer ordered by the original time they entered the queue. It made sense to us to peek at the message when publishing rather than dequeue it, so that when re-enqueueing after an exception 1) the cap is still honored and 2) the order of queued messages isn't altered. It's ok if another thread removes the message that's currently being published from the queue due to the cap, because all we have to do then is check if it's already been removed before removing it ourselves.
MQTTnet
MQTTnet is a high performance .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker). The implementation is based on the documentation from http://mqtt.org/.
Features
General
- Async support
- TLS 1.2 support for client and server (but not UWP servers)
- Extensible communication channels (i.e. In-Memory, TCP, TCP+TLS, WS)
- Lightweight (only the low level implementation of MQTT, no overhead)
- Performance optimized (processing ~70.000 messages / second)*
- Interfaces included for mocking and testing
- Access to internal trace messages
- Unit tested (~100 tests)
* Tested on local machine (Intel i7 8700K) with MQTTnet client and server running in the same process using the TCP channel. The app for verification is part of this repository and stored in /Tests/MQTTnet.TestApp.NetCore.
Client
- Communication via TCP (+TLS) or WS (WebSocket) supported
- Included core MqttClient with low level functionality
- Also included ManagedMqttClient which maintains the connection and subscriptions automatically. Also application messages are queued and re-scheduled for higher QoS levels automatically.
- Rx support (via another project)
- Compatible with Microsoft Azure IoT Hub
Server (broker)
- List of connected clients available
- Supports connected clients with different protocol versions at the same time
- Able to publish its own messages (no loopback client required)
- Able to receive every message (no loopback client required)
- Extensible client credential validation
- Retained messages are supported including persisting via interface methods (own implementation required)
- WebSockets supported (via ASP.NET Core 2.0, separate nuget)
- A custom message interceptor can be added which allows transforming or extending every received application message
- Validate subscriptions and deny subscribing of certain topics depending on requesting clients
Supported frameworks
- .NET Standard 1.3+
- .NET Core 1.1+
- .NET Core App 1.1+
- .NET Framework 4.5.2+ (x86, x64, AnyCPU)
- Mono 5.2+
- Universal Windows Platform (UWP) 10.0.10240+ (x86, x64, ARM, AnyCPU, Windows 10 IoT Core)
- Xamarin.Android 7.5+
- Xamarin.iOS 10.14+
Supported MQTT versions
- 5.0.0 (planned)
- 3.1.1
- 3.1.0
Nuget
This library is available as a nuget package: https://www.nuget.org/packages/MQTTnet/
Examples
Please find examples and the documentation at the Wiki of this repository (https://github.com/chkr1011/MQTTnet/wiki).
Contributions
If you want to contribute to this project just create a pull request. But only pull requests which are matching the code style of this library will be accepted. Before creating a pull request please have a look at the library to get an overview of the required style. Also additions and updates in the Wiki are welcome.
This project also listed at Open Collective (https://opencollective.com/mqttnet).
References
This library is used in the following projects:
- HA4IoT (Open Source Home Automation system for .NET, https://github.com/chkr1011/HA4IoT)
- MQTT Client Rx (Wrapper for Reactive Extensions, https://github.com/1iveowl/MQTTClient.rx)
- MQTT Tester (MQTT client test app for Android and iOS)
- Wirehome.Core (Open Source Home Automation system for .NET Core, https://github.com/chkr1011/Wirehome.Core)
If you use this library and want to see your project here please let me know.
MIT License
Copyright (c) 2017-2018 Christian Kratky
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.