This document describes how to create devices and permissions in the IoT Hub console and quickly try out device connection to IoT Hub over the MQTT protocol for message sending and receiving based on the mqtt_sample of the C-SDK.
Operations in Console
Creating product and device
1. Log in to the IoT Hub console and click Products on the left sidebar.
2. On the product list page, click Create Product.
3. On the pop-up product adding page, select the node type and product type, enter the product name, select the authentication method and data format, and enter the product description.
Then, click Confirm (select as shown below for directly connected general devices).
4. After the product is created, click Devices at the bottom of the generated product page.
5. On the device list page, click Add Device.
If the authentication method is certificate authentication, after the device name is entered, be sure to click Download in the pop-up window. The device key and device certificate in the downloaded package are used for authenticating the device during connection to IoT Hub.
If the authentication method is key authentication, after the device name is entered, the key of the added device will be displayed in the pop-up window.
Creating topic
1. On the generated product page, click Permissions.
2. On the permission list page, click Add Topic Permission.
3. In the topic permission pop-up window, enter data, set the operation permission to Subscribe and Publish, and click Confirm.
4. Then, the productID/\\${deviceName}/data topic will be created, and you can view all permissions of the product in the permission list on the product page.
Compiling and Running Demo
The following describes how to compile and run the mqtt_sample demo in the Linux environment (with a key-authenticated device as example).
1. Compile the SDK
1.1 Modify CMakeLists.txt to ensure that the following options exist:
set(BUILD_TYPE "release")
set(COMPILE_TOOLS "gcc")
set(PLATFORM "linux")
set(FEATURE_MQTT_COMM_ENABLED ON)
set(FEATURE_AUTH_MODE "KEY")
set(FEATURE_AUTH_WITH_NOTLS OFF)
set(FEATURE_DEBUG_DEV_INFO_USED OFF)
1.2.Run the following script for compilation.
./cmake_build.sh
1.3.The demo output is in the output/release/bin folder.
2. Enter the device information
Enter the information of the device created above on the IoT Hub platform in device_info.json.
The following log information shows that the demo reported data to /{productID}/{deviceName}/data through the Publish message type of MQTT, and that the server received and successfully processed the message.
The following log information shows that as the message reached the subscribed topic, it was pushed to the demo as-is by the server and entered the corresponding callback function.
INF|2019-09-12 21:28:21|mqtt_sample.c|on_message_callback(195): Receive Message With topicName:S3EUVBRJLB/test_device/data, payload:{"action":"publish_test", "count":"0"}
6. Observe logs in the console
Log in to the IoT Hub console, click the product name, and click Cloud Log on the top to view the message just reported.
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