Paho MQTT for C を使用した IoT Platform へのデバイスの接続 - IoT Platform - Alibaba Cloud - IoT Platform

Important notes

The steps in this topic are performed as a regular user. If an operation requires administrative permissions, prefix the command with sudo.

前提条件

プロダクトとデバイスは、IoT Platformコンソールのインスタンスに作成されます。デバイス証明書とMQTTエンドポイントが取得されます。証明書情報には、ProductKey、DeviceName、およびDeviceSecretが含まれます。詳細については、以下のトピックをご参照ください。

Prepare the development environment

This example uses Ubuntu 16.04 LTS as the development environment. Run the following commands to install the required dependencies.

sudo apt-get update
sudo apt-get install build-essential git sed cmake

Download the Paho MQTT C library

Run the following command to clone the Paho MQTT C library.
```
git clone https://github.com/eclipse/paho.mqtt.c.git
```
説明
This demo was created using the master branch. The commit id is f7799da95e347bbc930b201b52a1173ebbad45a7.
Run the following commands to compile and install the Paho library.
```
mkdir build
cmake ..
make -j
sudo make install
cd ..
rm -rf build
```

Connect to IoT Platform

Download the demo package. The decompressed package contains the following files:

File name	Description
`CMakeLists.txt`	The main configuration file for the project.
`src/samples/MQTTAsync_publish.c`	Contains the logic for connecting the device to IoT Platform and exchanging messages.
`src/samples/aiot_mqtt_sign.c`	Generates MQTT connection parameters. When `aiot_c_demo.c` runs, it calls the `aiotMqttSign()` function defined in this file to calculate the username, password, and clientId parameters.
`src/samples/CMakeLists.txt`	The configuration file for the demo project.

In the src/samples/MQTTAsync_publish.c file, update the device information (ProductKey, DeviceName, and DeviceSecret) with your device certificate information.

#define EXAMPLE_PRODUCT_KEY            "Your_ProductKey" 
#define EXAMPLE_DEVICE_NAME            "Your_DeviceName" 
#define EXAMPLE_DEVICE_SECRET          "Your_DeviceSecret"

In the src/samples/MQTTAsync_publish.c file, tcp://iot-0***********l.mqtt.iothub.aliyuncs.com:443 is the access domain name.

説明
For more information about the endpoint formats for public and Enterprise instances, see View instance endpoint information.
```
#define ADDRESS     "tcp://iot-0***********l.mqtt.iothub.aliyuncs.com:443"
```
Overwrite the original files in the Paho MQTT C library directory with the corresponding files from the demo package that you downloaded.

Run the following commands to compile the project.

mkdir build    // Run this command in the root directory of the project.
cd build
cmake ..
make -j

After the compilation is complete, go to the build directory and run the following command to start the program.

./src/samples/MQTTAsync_publish

If the program runs successfully, the following log output indicates that the device is connected to IoT Platform.

clientid: ty***1&a1****kc|timestamp=2524608000000,_v=paho-c-standard-1.0.0,securemode=3,signmethod=hmacsha256,lan=C|
username: ty***1&a1****kc
password: 1BB**************************************************3621
Waiting for publication of Hello World!
on topic /sys/a1*****kc/ty********1/thing/event/property/post for client
Successful connection
Message with token value 1 delivery confirmed
Successful disconnection