OVMS3-idf/examples/protocols/mqtt/wss/README.md

# ESP-MQTT MQTT over WSS Sample application
(See the README.md file in the upper level 'examples' directory for more information about examples.)

This example connects to the broker iot.eclipse.org over secure websockets and as a demonstration subscribes/unsubscribes and send a message on certain topic.

It uses ESP-MQTT library which implements mqtt client to connect to mqtt broker.

## How to use example

### Hardware Required

This example can be executed on any ESP32 board, the only required interface is WiFi and connection to internet.

### Configure the project

* Run `make menuconfig` (or `idf.py menuconfig` if using CMake build system)
* Configure Wi-Fi or Ethernet under "Example Connection Configuration" menu. See "Establishing Wi-Fi or Ethernet Connection" section in [examples/protocols/README.md](../../README.md) for more details.
* When using Make build system, set `Default serial port` under `Serial flasher config`.

Note how to create a PEM certificate for iot.eclipse.org:

```
openssl s_client -showcerts -connect iot.eclipse.org:8883 </dev/null 2>/dev/null|openssl x509 -outform PEM >iot_eclipse_org.pem
```

### Build and Flash

Build the project and flash it to the board, then run monitor tool to view serial output:

```
make -j4 flash monitor
```

(To exit the serial monitor, type ``Ctrl-]``.)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

## Example Output

```
I (3714) event: sta ip: 192.168.0.139, mask: 255.255.255.0, gw: 192.168.0.2
I (3714) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
I (3964) MQTT_CLIENT: Sending MQTT CONNECT message, type: 1, id: 0000
I (4164) MQTTWSS_EXAMPLE: MQTT_EVENT_CONNECTED
I (4174) MQTTWSS_EXAMPLE: sent publish successful, msg_id=41464
I (4174) MQTTWSS_EXAMPLE: sent subscribe successful, msg_id=17886
I (4174) MQTTWSS_EXAMPLE: sent subscribe successful, msg_id=42970
I (4184) MQTTWSS_EXAMPLE: sent unsubscribe successful, msg_id=50241
I (4314) MQTTWSS_EXAMPLE: MQTT_EVENT_PUBLISHED, msg_id=41464
I (4484) MQTTWSS_EXAMPLE: MQTT_EVENT_SUBSCRIBED, msg_id=17886
I (4484) MQTTWSS_EXAMPLE: sent publish successful, msg_id=0
I (4684) MQTTWSS_EXAMPLE: MQTT_EVENT_SUBSCRIBED, msg_id=42970
I (4684) MQTTWSS_EXAMPLE: sent publish successful, msg_id=0
I (4884) MQTT_CLIENT: deliver_publish, message_length_read=19, message_length=19
I (4884) MQTTWSS_EXAMPLE: MQTT_EVENT_DATA
TOPIC=/topic/qos0
DATA=data
I (5194) MQTT_CLIENT: deliver_publish, message_length_read=19, message_length=19
I (5194) MQTTWSS_EXAMPLE: MQTT_EVENT_DATA
TOPIC=/topic/qos0
DATA=data
```