Cayenne MQTT C Library

The Cayenne MQTT C Library provides functions to easily connect to the Cayenne IoT project builder.

This library bundles the Eclipse Paho MQTT C/C++ client.

Repository Structure

• src - The library source code.
  • CayenneMQTTClient - Platform independent Cayenne C library using the Paho MQTT C library. To create platform specific versions of this library networking and timer code for the platform are required.
  • CayenneUtils - Common code for creating and parsing Cayenne topics and payloads. This code can be used with any MQTT client.
  • MQTTCommon - Common Paho MQTT C code used by both the C and C++ libraries.
  • Platform - Platform specific networking and timer code, as well as test and example applications.
    • Linux - Linux C networking and timer code, as well as test and example applications. Test and example files can be built using the makefile.
    • FreeBSD - FreeBSD test and example files makefiles that use the Linux test and example code to build.
    • Windows - Windows C networking and timer code, as well as test and example applications. Test and example files can be built using Visual Studio 2017.

Building Examples

To build on Linux switch to the root folder and run: make

To build on FreeBSD switch to the src\Platform\FreeBSD folder and run: make

To build on Windows load the Visual Studio 2017 solution file at src\Platform\Windows\Cayenne.sln and build the project.

Adding Additional Platforms

The Cayenne MQTT client code is platform independent but it requires platform specific code to create timers and to read and write data over the network. To add support for additional platforms you will need to create platform specific timer and networking code.

• Timer - This struct and associated functions are used to create countdown timers. They are described in the PlatformHeader.h file. An example implementation for Linux is under the Platform/Linux folder.
• Network - This struct and associated functions are used to read and write data over the network. They are described in the PlatformHeader.h file. An example implementation for Linux is under the Platform/Linux folder.

After creating new platform specific timer and networking code you can include their headers in PlatformHeader.h to make the Cayenne MQTT client use your code.

Cayenne MQTT Libraries

• Cayenne-MQTT-C - C version of the Cayenne MQTT Library.
• Cayenne-MQTT-CPP - C++ version of the Cayenne MQTT Library.
• Cayenne-MQTT-Arduino - Arduino version of the Cayenne MQTT Library.
• Cayenne-MQTT-mbed - mbed version of the Cayenne MQTT Library. This is also available on the mbed developer site here.