esp-idf/examples/protocols/mqtt5

Supported Targets	ESP32	ESP32-C3	ESP32-S2	ESP32-S3

ESP-MQTT sample application

(See the README.md file in the upper level 'examples' directory for more information about examples.)

This example connects to the broker URI selected using idf.py menuconfig (using mqtt tcp transport) and as a demonstration subscribes/unsubscribes and send a message on certain topic. (Please note that the public broker is maintained by the community so may not be always available, for details please see this disclaimer)

Note: If the URI equals FROM_STDIN then the broker address is read from stdin upon application startup (used for testing)

It uses ESP-MQTT library which implements mqtt client to connect to mqtt broker with MQTT version 5.

The more details about MQTT v5, please refer to official website

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

• Open the project configuration menu (idf.py menuconfig)
• Configure Wi-Fi or Ethernet under "Example Connection Configuration" menu. See "Establishing Wi-Fi or Ethernet Connection" section in examples/protocols/README.md for more details.
• MQTT v5 protocol (CONFIG_MQTT_PROTOCOL_5) under "ESP-MQTT Configurations" menu is enabled by sdkconfig.defaults.

Build and Flash

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

idf.py -p PORT 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 (5119) esp_netif_handlers: example_connect: sta ip: 192.168.3.143, mask: 255.255.255.0, gw: 192.168.3.1
I (5119) example_connect: Got IPv4 event: Interface "example_connect: sta" address: 192.168.3.143
I (5619) example_connect: Got IPv6 event: Interface "example_connect: sta" address: fe80:0000:0000:0000:c64f:33ff:fe24:6645, type: ESP_IP6_ADDR_IS_LINK_LOCAL
I (5619) example_connect: Connected to example_connect: sta
I (5629) example_connect: - IPv4 address: 192.168.3.143
I (5629) example_connect: - IPv6 address: fe80:0000:0000:0000:c64f:33ff:fe24:6645, type: ESP_IP6_ADDR_IS_LINK_LOCAL
I (5649) MQTT5_EXAMPLE: Other event id:7
W (6299) wifi:<ba-add>idx:0 (ifx:0, 34:29:12:43:c5:40), tid:7, ssn:0, winSize:64
I (7439) MQTT5_EXAMPLE: MQTT_EVENT_CONNECTED
I (7439) MQTT5_EXAMPLE: sent publish successful, msg_id=53118
I (7439) MQTT5_EXAMPLE: sent subscribe successful, msg_id=41391
I (7439) MQTT5_EXAMPLE: sent subscribe successful, msg_id=13695
I (7449) MQTT5_EXAMPLE: sent unsubscribe successful, msg_id=55594
I (7649) mqtt5_client: MQTT_MSG_TYPE_PUBACK return code is -1
I (7649) MQTT5_EXAMPLE: MQTT_EVENT_PUBLISHED, msg_id=53118
I (8039) mqtt5_client: MQTT_MSG_TYPE_SUBACK return code is 0
I (8049) MQTT5_EXAMPLE: MQTT_EVENT_SUBSCRIBED, msg_id=41391
I (8049) MQTT5_EXAMPLE: sent publish successful, msg_id=0
I (8059) mqtt5_client: MQTT_MSG_TYPE_SUBACK return code is 2
I (8059) MQTT5_EXAMPLE: MQTT_EVENT_SUBSCRIBED, msg_id=13695
I (8069) MQTT5_EXAMPLE: sent publish successful, msg_id=0
I (8079) MQTT5_EXAMPLE: MQTT_EVENT_DATA
I (8079) MQTT5_EXAMPLE: key is board, value is esp32
I (8079) MQTT5_EXAMPLE: key is u, value is user
I (8089) MQTT5_EXAMPLE: key is p, value is password
I (8089) MQTT5_EXAMPLE: payload_format_indicator is 1
I (8099) MQTT5_EXAMPLE: response_topic is /topic/test/response
I (8109) MQTT5_EXAMPLE: correlation_data is 123456
I (8109) MQTT5_EXAMPLE: content_type is 
I (8119) MQTT5_EXAMPLE: TOPIC=/topic/qos1
I (8119) MQTT5_EXAMPLE: DATA=data_3
I (8129) mqtt5_client: MQTT_MSG_TYPE_UNSUBACK return code is 0
I (8129) MQTT5_EXAMPLE: MQTT_EVENT_UNSUBSCRIBED, msg_id=55594
I (8139) mqtt_client: Client asked to disconnect
I (9159) MQTT5_EXAMPLE: MQTT_EVENT_DISCONNECTED