TSL model development

Prerequisites

• You have obtained device credentials.

• You have added a TSL model.

• You have downloaded C LinkSDK Extended.

Procedure

The following sequence diagram shows the basic procedure for using a TSL model. The device application ./demos/data_model_basic_demo.c is used as an example. For more information about the APIs, see aiot_dm_api.h.

Step 1: Initialize the device

Create a device handle and establish a device connection.

static void* demo_device_init(char *product_key, char *device_name, char *device_secret, char *host, uint16_t port)
{
    int32_t res = STATE_SUCCESS;
    /* Create a device. */
    void *device = aiot_device_create(product_key, device_name);
    if (device == NULL) {
        printf("device create failed\n");
        return NULL;
    }
    /* Set the device secret. */
    aiot_device_set_device_secret(device, device_secret);

    /* Initialize the connection configuration parameters. */
    aiot_linkconfig_t* config = aiot_linkconfig_init(protocol);
    /* Set the host and port of the server. */
    aiot_linkconfig_host(config, host, port);

    /* Set the device connection parameters. */
    aiot_device_set_linkconfig(device, config);
    
    /* Establish a device connection. */
    res = aiot_device_connect(device);
    if (res < STATE_SUCCESS) {
        /* If the connection attempt fails, destroy the MQTT instance and revoke the resources. */
        aiot_linkconfig_deinit(&config);
        aiot_device_delete(&device);
        printf("aiot_device_connect failed: -0x%04X\n\r\n", -res);
        return NULL;
    }

    /* If the connection is established, return the device object. */
    aiot_linkconfig_deinit(&config);
    return device;
}

Step 2: Report properties

Property reporting is typically used to report the device status. The following example shows how to report that the light is off.

 /* Example of reporting a property. */
    char *property_params = "{\"LightSwitch\": 0}";
    aiot_device_dm_property_post(device_client, property_params, 1);

Step 3: Set properties

When a device receives a message to set a property, it executes the corresponding callback function. The message type is AIOT_DMRECV_PROPERTY_SET. For demonstration purposes, the following example only prints the property setting.

/* Cloud -> Device: Example of processing a property setting message. The example only prints the message. */
static void demo_dm_msg_property_set_callback(void *device, const aiot_dm_msg_t *dm_msg, void *userdata)
{
    printf("demo_dm_msg_property_set_callback params = %.*s\r\n",
        dm_msg->data.property_set.params_len,
        dm_msg->data.property_set.params);

    /* TODO: Demonstrate a sync reply. */
    char *reply_data = "{}";
    aiot_device_dm_propertyset_reply(device, dm_msg->context, 200, reply_data);

    /* TODO: Demonstrate an asynchronous reply [not replying in the callback function]. You need to back up the message context for the reply. */
    /*
    void *context = aiot_dm_msg_context_clone(dm_msg->context);
    aiot_device_dm_propertyset_reply(device, dm_msg->context, 200, reply_data);
    aiot_dm_msg_context_free(context);
    */
}

Step 4: Report events

Events typically contain information, alerts, and faults that require processing by external systems. The following example simulates a fault report with an error code of -1.

 char *event_id = "Error";
    char *event_params = "{\"ErrorCode\": -1}";
    aiot_device_dm_event_post(device_client, event_id, event_params, 1);

Step 5: Invoke services

Services provide instructions or methods for a device that can be invoked externally. For example, turning on a light can be implemented as a service invocation. The following example demonstrates a service invocation where the callback simply prints the information.

/* Cloud -> Device: Example of processing a service invocation message. The example only prints the message. */
static void demo_dm_msg_service_invoke_callback(void *device, const aiot_dm_msg_t *dm_msg, void *userdata)
{
    printf("demo_dm_msg_service_invoke_callback service_id %s, params = %.*s\r\n",
        dm_msg->data.service_invoke.service_id,
        dm_msg->data.service_invoke.params_len,
        dm_msg->data.service_invoke.params);

    /* TODO: Demonstrate a sync reply. */
    char *reply_data = "{}";
    aiot_device_dm_service_reply(device, dm_msg->context, dm_msg->data.service_invoke.service_id, 200, reply_data);

    /* TODO: Demonstrate an asynchronous reply [not replying in the callback function]. You need to back up the message context for the reply. */
    /*
    void *context = aiot_dm_msg_context_clone(dm_msg->context);
    aiot_device_dm_propertyset_reply(device, dm_msg->context, 200, reply_data);
    aiot_dm_msg_context_free(context);
    */
}

Step 6: Deinitialize the device

 /* Disconnect the device and revoke its resources. */
    demo_device_deinit(device_client);