DISCLAIMER: The GDPaho plugin (also an MQTT client) is more stable and better maintained, so I strongly recommend using it instead https://github.com/GDWired/GDPaho.
A wrapping of libmosquitto (https://mosquitto.org) able to make MQTT clients in Godot, is a part of GDWired (https://github.com/GDWired).
The picture represent the demo project:
- The first line is the subscription parameters, subscribe to the SIN topic and expect JSON formatted data like [t,sin(t)] and plot it.
- The second line is the pulisher parameters, publish JSON formatted data to the SIN topic [t,sin(t)].
- The last line sends the text from the first edit line to the topic DATA (the second edit line subscribes to DATA and displays the sent text).
Works on editor and exports for Windows, Linux and macOS. By default, the Windows version is compiled without pthreads and loop_start is not usable (mosquitto version 2.1 should solve this thread problem). You can recompile it to use loop_start or use this workaround:
var _loop_thread: Thread = null
onready var _mqtt_client: Reference = preload("res://addons/GDMosquitto/GDMosquitto.gdnlib").new()
func _ready() -> void:
_mqtt_client.initialise(client_id, clean_session)
_mqtt_client.broker_connect(host, port, keep_alive)
_loop_start_supported = not (_mqtt_client.loop_start() == GDMosquitto.RC.MOSQ_ERR_NOT_SUPPORTED)
if not _loop_start_supported:
_mqtt_client.threaded_set(true)
_loop_thread = Thread.new()
_loop_thread.start(self, "_mqtt_client_loop")
func _mqtt_client_loop() -> void:
_mqtt_client.loop_forever(0)
func _notification(what: int) -> void:
if what == NOTIFICATION_WM_QUIT_REQUEST:
_mqtt_client.broker_disconnect()
if _loop_start_supported:
_mqtt_client.loop_stop(false)
else:
_loop_thread.wait_to_finish()However, the behavior under Windows is not exactly the same. If QoS 0 is used, there are some lost packets (it's ok with QoS 1). And there is sometimes a random crash at startup... If your project is simple, I recommande to use my light implementation of paho.mqtt here (https://github.com/GDWired/GDPaho) available on Windows and Linux (macOS is WIP).
Precompiled for Win64, macOS Universal (arm64 and x86_64) and Linux x86_64. Just copy/past the folder GDMosquitto from demo/addons into your project.
If you need specific build (Win32 or Linux arm64 for exemple)
- Install Mosquitto (brew install mosquitto, apt install mosquitto ...)
- [Windows] Add mosquitto and mosquitto/devel to the path
- Run git clone --recurse-submodules https://github.com/jferdelyi/GDMosquitto.git
- Install the Godot dependencies (https://docs.godotengine.org/en/stable/development/compiling/index.html)
- Run scons on the root folder.
- Start Godot3.5 and open the project in the demo folder (or copy/past the folder GDMosquitto in addons into your project)
## Tested ##
# Initialize the client
# @param p_id string to use as the client id.
# @param p_clean_session set to true to instruct the broker to clean all messages and subscriptions on disconnect, false to instruct it to keep them
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.initialise(client_id, clean_session)
# Connect the client to the broker (server)
# @param broker_address the broker address
# @param broker_port the broker port
# @param broker_keep_alive keep alive time
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.broker_connect(broker_address, broker_port, broker_keep_alive)
# Disconnect the client
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.broker_disconnect()
# Start the main loop (Not working on Windows)
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.loop_start()
# Start infinite loop
# @param timeout maximum number of milliseconds to wait for network activity before timing out. Set to 0 for instant return. Set negative to use the default of 1000ms
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.loop_forever(timeout)
# Stop the main loop
# @param force set to true to force thread cancellation. If false, <mosquitto_disconnect> must have already been called
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.loop_stop(force)
# Used to tell the library that your application is using threads, but not loop_start
# @param threaded true to tell the library that your application is using threads
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.threaded_set(threaded)
# Subscribe to a topic
# @param topic the name of the topic
# @param qos the QoS used
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.subscribe(topic, qos)
# Unsubscribe to a topic
# @param topic the name of the topic
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.unsubscribe(topic)
# Publish to a topic
# @param topic the name of the topic
# @param data the data to send
# @param qos the QoS used
# @param retain if true the data is retained
# @return the reason code, if something wrong happen. 0 = OK (see https://docs.oasis-open.org/mqtt/mqtt/v5.0/os/mqtt-v5.0-os.html#_Toc3901031)
_mqtt_client.publish(topic, data, qos, retain)About export on Android:
- Mosquitto build is OK
- GDMosquitto build OK
- APK/AAB build OK
- Runtime KO (on emulator, the application is open but no GDNative call works)
Android Mosquitto build (on macOS):
mkdir build
cd build
cmake -DANDROID_NDK=<NDK_PATH> -DANDROID_ABI="arm64-v8a" -DANDROID_NDK_HOST_X64="YES" -DANDROID_TOOLCHAIN_NAME="arm-linux-androideabi-4.9" -DCMAKE_TOOLCHAIN_FILE="<NDK_PATH>/build/cmake/android.toolchain.cmake" -DWITH_TLS=OFF -DWITH_THREADING=OFF -DANDROID_TOOLCHAIN=clang ..
cmake --build .
Not implemented methods
- opts_set, I have implemented set_protocol_version for the protocol version, but I don't know how to implement set_ssl_ctx (do nothing for now), if someone needs it, I will ask
- message_retry_set (no effect now, will never be implemented)
Never tested methods (returns rc=0 but has never been tested further)
- reinitialise
- will_set
- will_clear
- username_pw_set
- connect_async
- connect(bind)
- connect_async(bind)
- reconnect
- reconnect_async
- reconnect_delay_set
- max_inflight_messages_set
- user_data_set
- tls_set
- tls_opts_set
- tls_insecure_set
- tls_psk_set
- set_protocol_version
- loop
- loop_misc
- loop_write
- loop_read
- want_write
- threaded_set
- socks5_set
QoS behaviour is not really tested (QoS 0 and 1 durring tests) and connect with flags seems not returns good flags (always 0).