86 lines
2.5 KiB
Markdown
86 lines
2.5 KiB
Markdown
# pubsubc
|
|
|
|
This is a minimal MQTT client library in C.
|
|
|
|
It comes with an adaption layer for the ioLibrary_Driver for the
|
|
WizNet chips which can be found here https://github.com/Wiznet/ioLibrary_Driver.
|
|
|
|
You find a fork with a Makefile a STMCubeMX generated project here
|
|
https://home.hottis.de/gitlab/wolutator/ioLibrary_Driver/-/tree/WolfgangsOwnBranch.
|
|
|
|
Using this adaption layer you should find it easy to adjust it for
|
|
other platforms.
|
|
|
|
This work is directly derived from the famous PubSubClient library
|
|
of Nick O'Leary, which can be found at https://pubsubclient.knolleary.net/
|
|
|
|
It is most or less a plain C rewrite.
|
|
|
|
All honour for this working MQTT client library goes to Nick O'Leary,
|
|
all blame for bugs in the C port shall go to me.
|
|
|
|
|
|
## API
|
|
|
|
|
|
The library provides the following functions:
|
|
|
|
|
|
### Initialization
|
|
|
|
void mqttClientInit(mqttClient_t *mqttClient, client_t *client, callback_t callback);
|
|
|
|
Initializes the MQTT client, handover a client handle according to the definition
|
|
from ``platformAdaption.h`` and a callback function for incoming messages.
|
|
|
|
Implement this callback function for incoming messages with this footprint:
|
|
|
|
typedef void (*callback_t)(char*, uint8_t*, uint16_t);
|
|
|
|
### Connect
|
|
|
|
bool mqttConnect(mqttClient_t *mqttClient,
|
|
uint8_t *address, uint16_t port,
|
|
const char *id,
|
|
const char *user, const char *pass,
|
|
const char *willTopic, uint8_t willQos,
|
|
bool willRetain, const char *willMessage,
|
|
bool cleanSession);
|
|
|
|
In the original C++ implementation multiple variants of the ``connect``method are available
|
|
with less and lesser arguments. Unfortunately, in C this is no option. If you don't care
|
|
about authentication and the whole will stuff you can call it
|
|
|
|
mqttConnect(&mqttClient, brokerAddress, brokerPort, clientId, NULL, NULL, NULL, 0, false, NULL, false);
|
|
|
|
### Disconnect
|
|
|
|
void mqttDisconnect(mqttClient_t *mqttClient);
|
|
|
|
### Publish
|
|
|
|
bool publish(mqttClient_t *mqttClient,
|
|
const char *topic,
|
|
const uint8_t *payload, uint16_t plength,
|
|
bool retained);
|
|
|
|
### Subscribe and Unsubscribe
|
|
|
|
bool subscribe(mqttClient_t *mqttClient,
|
|
const char *topic, uint8_t qos);
|
|
|
|
bool unsubscribe(mqttClient_t *mqttClient,
|
|
const char* topic);
|
|
|
|
### Loop
|
|
|
|
bool mqttLoop(mqttClient_t *mqttClient);
|
|
|
|
Call this function in your idle loop. For my own part, I've implemented a time-triggered system
|
|
and call it with a period of 100ms.
|
|
|
|
### Connection status
|
|
|
|
bool mqttConnected(mqttClient_t *mqttClient);
|
|
|