116 lines
3.5 KiB
ReStructuredText
116 lines
3.5 KiB
ReStructuredText
ESP-MQTT
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========
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Overview
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--------
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ESP-MQTT is an implementation of MQTT protocol client (MQTT is a lightweight publish/subscribe messaging protocol).
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Features
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--------
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* supports MQTT over TCP, SSL with mbedtls, MQTT over Websocket, MQTT over Websocket Secure.
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* Easy to setup with URI
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* Multiple instances (Multiple clients in one application)
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* Support subscribing, publishing, authentication, will messages, keep alive pings and all 3 QoS levels (it should be a fully functional client).
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Application Example
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-------------------
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* :example:`protocols/mqtt/tcp`: MQTT over tcp, default port 1883
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* :example:`protocols/mqtt/ssl`: MQTT over tcp, default port 8883
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* :example:`protocols/mqtt/ws`: MQTT over Websocket, default port 80
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* :example:`protocols/mqtt/wss`: MQTT over Websocket Secure, default port 443
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Configuration
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-------------
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URI
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^^^
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- Curently support ``mqtt``, ``mqtts``, ``ws``, ``wss`` schemes
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- MQTT over TCP samples:
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- ``mqtt://iot.eclipse.org``: MQTT over TCP, default port 1883:
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- ``mqtt://iot.eclipse.org:1884`` MQTT over TCP, port 1884:
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- ``mqtt://username:password@iot.eclipse.org:1884`` MQTT over TCP,
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port 1884, with username and password
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- MQTT over SSL samples:
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- ``mqtts://iot.eclipse.org``: MQTT over SSL, port 8883
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- ``mqtts://iot.eclipse.org:8884``: MQTT over SSL, port 8884
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- MQTT over Websocket samples:
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- ``ws://iot.eclipse.org:80/ws``
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- MQTT over Websocket Secure samples:
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- ``wss://iot.eclipse.org:443/ws``
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- Minimal configurations:
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.. code:: c
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const esp_mqtt_client_config_t mqtt_cfg = {
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.uri = "mqtt://iot.eclipse.org",
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// .user_context = (void *)your_context
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};
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esp_mqtt_client_handle_t client = esp_mqtt_client_init(&mqtt_cfg);
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esp_mqtt_client_register_event(client, ESP_EVENT_ANY_ID, mqtt_event_handler, client);
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esp_mqtt_client_start(client);
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- Note: By default mqtt client uses event loop library to post related mqtt events (connected, subsribed, published, etc.)
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- If there are any options related to the URI in
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``esp_mqtt_client_config_t``, the option defined by the URI will be
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overridden. Sample:
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.. code:: c
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const esp_mqtt_client_config_t mqtt_cfg = {
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.uri = "mqtt://iot.eclipse.org:1234",
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.port = 4567,
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};
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//MQTT client will connect to iot.eclipse.org using port 4567
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SSL
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^^^
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- Get certificate from server, example: ``iot.eclipse.org``
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``openssl s_client -showcerts -connect iot.eclipse.org:8883 </dev/null 2>/dev/null|openssl x509 -outform PEM >iot_eclipse_org.pem``
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- Check the sample application: ``examples/mqtt_ssl``
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- Configuration:
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.. code:: cpp
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const esp_mqtt_client_config_t mqtt_cfg = {
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.uri = "mqtts://iot.eclipse.org:8883",
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.event_handle = mqtt_event_handler,
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.cert_pem = (const char *)iot_eclipse_org_pem_start,
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};
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For more options on ``esp_mqtt_client_config_t``, please refer to API reference below
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Change settings in ``menuconfig``
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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::
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make menuconfig
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-> Component config -> ESP-MQTT Configuration
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- :ref:`CONFIG_MQTT_PROTOCOL_311`: Enables 3.1.1 version of MQTT protocol
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- :ref:`CONFIG_MQTT_TRANSPORT_SSL`, :ref:`CONFIG_MQTT_TRANSPORT_WEBSOCKET`: Enables specific MQTT transport layer, such as SSL, WEBSOCKET, WEBSOCKET_SECURE
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- :ref:`CONFIG_MQTT_CUSTOM_OUTBOX`: Disables default implementation of mqtt_outbox, so a specific implementaion can be supplied
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API Reference
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-------------
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.. include:: /_build/inc/mqtt_client.inc
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